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Bakker J. Neurobiological characteristics associated with gender identity: Findings from neuroimaging studies in the Amsterdam cohort of children and adolescents experiencing gender incongruence. Horm Behav 2024; 164:105601. [PMID: 39029340 DOI: 10.1016/j.yhbeh.2024.105601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Revised: 07/05/2024] [Accepted: 07/05/2024] [Indexed: 07/21/2024]
Abstract
This review has been based on my invited lecture at the annual meeting of the Society for Behavioral Neuroendocrinology in 2023. Gender incongruence is defined as a marked and persistent incongruence between an individual's experienced gender and the sex assigned at birth. A prominent hypothesis on the etiology of gender incongruence proposes that it is related to an altered or less pronounced sexual differentiation of the brain. This hypothesis has primarily been based on postmortem studies of the hypothalamus in transgender individuals. To further address this hypothesis, a series of structural and functional neuroimaging studies were conducted in the Amsterdam cohort of children and adolescents experiencing gender incongruence. Additional research objectives were to determine whether any sex and gender differences are established before or after puberty, as well as whether gender affirming hormone treatment would affect brain development and function. We found some evidence in favor of the sexual differentiation hypothesis at the functional level, but this was less evident at the structural level. We also observed some specific transgender neural signatures, suggesting that they might present a unique brain phenotype rather than being shifted towards either end of the male-female spectrum. Our results further suggest that the years between childhood and mid-adolescence represent an important period in which puberty-related factors influence several neural characteristics, such as white matter development and functional connectivity patterns, in both a sex and gender identity specific way. These latter observations thus lead to the important question about the possible negative consequences of delaying puberty on neurodevelopment. To further address this question, larger-scale, longitudinal studies are required to increase our understanding of the possible neurodevelopmental impacts of delaying puberty in transgender youth.
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Affiliation(s)
- Julie Bakker
- GIGA Neurosciences, University of Liège, Belgium.
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2
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Handschuh PA, Reed MB, Murgaš M, Vraka C, Kaufmann U, Nics L, Klöbl M, Ozenil M, Konadu ME, Patronas EM, Spurny-Dworak B, Hahn A, Hacker M, Spies M, Baldinger-Melich P, Kranz GS, Lanzenberger R. Effects of gender-affirming hormone therapy on gray matter density, microstructure and monoamine oxidase A levels in transgender subjects. Neuroimage 2024; 297:120716. [PMID: 38955254 DOI: 10.1016/j.neuroimage.2024.120716] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2024] [Revised: 06/14/2024] [Accepted: 06/29/2024] [Indexed: 07/04/2024] Open
Abstract
MAO-A catalyzes the oxidative degradation of monoamines and is thus implicated in sex-specific neuroplastic processes that influence gray matter (GM) density (GMD) and microstructure (GMM). Given the exact monitoring of plasma hormone levels and sex steroid intake, transgender individuals undergoing gender-affirming hormone therapy (GHT) represent a valuable cohort to potentially investigate sex steroid-induced changes of GM and concomitant MAO-A density. Here, we investigated the effects of GHT over a median time period of 4.5 months on GMD and GMM as well as MAO-A distribution volume. To this end, 20 cisgender women, 11 cisgender men, 20 transgender women and 10 transgender men underwent two MRI scans in a longitudinal design. PET scans using [11C]harmine were performed before each MRI session in a subset of 35 individuals. GM changes determined by diffusion weighted imaging (DWI) metrics for GMM and voxel based morphometry (VBM) for GMD were estimated using repeated measures ANOVA. Regions showing significant changes of both GMM and GMD were used for the subsequent analysis of MAO-A density. These involved the fusiform gyrus, rolandic operculum, inferior occipital cortex, middle and anterior cingulum, bilateral insula, cerebellum and the lingual gyrus (post-hoc tests: pFWE+Bonferroni < 0.025). In terms of MAO-A distribution volume, no significant effects were found. Additionally, the sexual desire inventory (SDI) was applied to assess GHT-induced changes in sexual desire, showing an increase of SDI scores among transgender men. Changes in the GMD of the bilateral insula showed a moderate correlation to SDI scores (rho = - 0.62, pBonferroni = 0.047). The present results are indicative of a reliable influence of gender-affirming hormone therapy on 1) GMD and GMM following an interregional pattern and 2) sexual desire specifically among transgender men.
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Affiliation(s)
- P A Handschuh
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Austria
| | - M B Reed
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Austria
| | - M Murgaš
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Austria
| | - C Vraka
- Department of Biomedical Imaging and Image-guided Therapy, Division of Nuclear Medicine, Medical University of Vienna, Austria
| | - U Kaufmann
- Department of Obstetrics and Gynecology, Medical University of Vienna, Austria
| | - L Nics
- Department of Biomedical Imaging and Image-guided Therapy, Division of Nuclear Medicine, Medical University of Vienna, Austria
| | - M Klöbl
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Austria
| | - M Ozenil
- Department of Biomedical Imaging and Image-guided Therapy, Division of Nuclear Medicine, Medical University of Vienna, Austria
| | - M E Konadu
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Austria
| | - E M Patronas
- Department of Biomedical Imaging and Image-guided Therapy, Division of Nuclear Medicine, Medical University of Vienna, Austria
| | - B Spurny-Dworak
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Austria
| | - A Hahn
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Austria
| | - M Hacker
- Department of Biomedical Imaging and Image-guided Therapy, Division of Nuclear Medicine, Medical University of Vienna, Austria
| | - M Spies
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Austria
| | - P Baldinger-Melich
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Austria
| | - G S Kranz
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Austria; Department of Rehabilitation Sciences, Hong Kong Polytechnic University, Hong Kong, China
| | - R Lanzenberger
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Austria.
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Muhsin SM, Yahya F, Parachottil R, Shaikh S, Chin AHB. Sex Reassignment Surgery, Marriage, and Reproductive Rights of Intersex and Transgender People in Sunni Islam. ARCHIVES OF SEXUAL BEHAVIOR 2024; 53:1681-1694. [PMID: 38383942 DOI: 10.1007/s10508-024-02813-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2023] [Revised: 01/09/2024] [Accepted: 01/10/2024] [Indexed: 02/23/2024]
Abstract
The traditional gender binary constitutes an integral aspect of Islamic social ethics, which has a pivotal role in shaping religious obligations, legal proceedings, and interpersonal judgments within Muslim communities. Within the familial sphere, this gender binary underscores fundamental responsibilities encompassing parenthood, filial duties, and inheritance rights. Recent years have witnessed a growing challenge to the traditional concept of the gender binary within Islamic societies. This shift is driven by increasing social libertarianism that emphasizes gender fluidity and individual choice. Hence, this article aims to critically scrutinize evolving discussions and controversies about the rights of intersex and transgender individuals, particularly issues relating to sex reassignment or gender-affirming surgery, marriage, and reproduction, from the perspective of the Sunni tradition of Islam. To support the various interpretations and insights presented here, a comprehensive and rigorous analysis is carried out on various religious texts and scholarly sources to elucidate the theological and jurisprudential positions on gender issues. It is thus concluded that Shariah offers greater flexibility in the treatment of intersex individuals compared to those with gender dysphoria because the intersex condition is viewed as a physical impairment that is not the choice of the afflicted individual. By contrast, in the case of individuals with gender dysphoria, they are willfully attempting to change their recognized biological sex, that God had naturally given to them at birth. Therefore, it is recommended that such transgender individuals deserve respectful psychological and social rehabilitation with help and guidance from religious authorities, their families, and communities.
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Affiliation(s)
- Sayyed Mohamed Muhsin
- Department of Fiqh and Usul Al-Fiqh, AHAS KIRKHS, International Islamic University Malaysia, Gombak, Malaysia
| | - Firdaus Yahya
- Syariah Consultancy Education & Training, Singapore Post Centre, Singapore, Singapore
| | - Rasheed Parachottil
- Department of Study of Religion, Darul Huda Islamic University, Chemmad, Kerala, India
| | - Sirajuddin Shaikh
- Department of Study of Religion, Darul Huda Islamic University, Chemmad, Kerala, India
| | - Alexis Heng Boon Chin
- Singapore Fertility and IVF Consultancy Pvt Ltd., 531A Upper Cross Street, #04-95, Hong Lim Complex, Singapore, 051531, Singapore.
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4
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Anger JT, Case LK, Baranowski AP, Berger A, Craft RM, Damitz LA, Gabriel R, Harrison T, Kaptein K, Lee S, Murphy AZ, Said E, Smith SA, Thomas DA, Valdés Hernández MDC, Trasvina V, Wesselmann U, Yaksh TL. Pain mechanisms in the transgender individual: a review. FRONTIERS IN PAIN RESEARCH 2024; 5:1241015. [PMID: 38601924 PMCID: PMC11004280 DOI: 10.3389/fpain.2024.1241015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Accepted: 01/25/2024] [Indexed: 04/12/2024] Open
Abstract
Specific Aim Provide an overview of the literature addressing major areas pertinent to pain in transgender persons and to identify areas of primary relevance for future research. Methods A team of scholars that have previously published on different areas of related research met periodically though zoom conferencing between April 2021 and February 2023 to discuss relevant literature with the goal of providing an overview on the incidence, phenotype, and mechanisms of pain in transgender patients. Review sections were written after gathering information from systematic literature searches of published or publicly available electronic literature to be compiled for publication as part of a topical series on gender and pain in the Frontiers in Pain Research. Results While transgender individuals represent a significant and increasingly visible component of the population, many researchers and clinicians are not well informed about the diversity in gender identity, physiology, hormonal status, and gender-affirming medical procedures utilized by transgender and other gender diverse patients. Transgender and cisgender people present with many of the same medical concerns, but research and treatment of these medical needs must reflect an appreciation of how differences in sex, gender, gender-affirming medical procedures, and minoritized status impact pain. Conclusions While significant advances have occurred in our appreciation of pain, the review indicates the need to support more targeted research on treatment and prevention of pain in transgender individuals. This is particularly relevant both for gender-affirming medical interventions and related medical care. Of particular importance is the need for large long-term follow-up studies to ascertain best practices for such procedures. A multi-disciplinary approach with personalized interventions is of particular importance to move forward.
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Affiliation(s)
- Jennifer T. Anger
- Department of Urology, University of California San Diego, San Diego, CA, United States
| | - Laura K. Case
- Department of Anesthesiology, University of California San Diego, San Diego, CA, United States
| | - Andrew P. Baranowski
- Pelvic Pain Medicine and Neuromodulation, University College Hospital Foundation Trust, University College London, London, United Kingdom
| | - Ardin Berger
- Anesthesiology, Perioperative and Pain Medicine, Stanford University, Stanford, CA, United States
| | - Rebecca M. Craft
- Department of Psychology, Washington State University, Pullman, WA, United States
| | - Lyn Ann Damitz
- Division of Plastic and Reconstructive Surgery, University of North Carolina, Chapel Hill, NC, United States
| | - Rodney Gabriel
- Division of Regional Anesthesia, University of California San Diego, San Diego, CA, United States
| | - Tracy Harrison
- Department of OB/GYN & Reproductive Sciences, University of California San Diego, San Diego, CA, United States
| | - Kirsten Kaptein
- Division of Plastic Surgery, University of California San Diego, San Diego, CA, United States
| | - Sanghee Lee
- Department of Urology, University of California San Diego, San Diego, CA, United States
| | - Anne Z. Murphy
- Neuroscience Institute, Georgia State University, Atlanta, GA, United States
| | - Engy Said
- Division of Regional Anesthesia, University of California San Diego, San Diego, CA, United States
| | - Stacey Abigail Smith
- Division of Infection Disease, The Hope Clinic of Emory University, Atlanta, GA, United States
| | - David A. Thomas
- Office of Research on Women's Health, National Institutes of Health, Bethesda, MD, United States
| | - Maria del C. Valdés Hernández
- Department of Neuroimaging Sciences, Center for Clinical Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Victor Trasvina
- Department of Urology, University of California San Diego, San Diego, CA, United States
| | - Ursula Wesselmann
- Departments of Anesthesiology and Perioperative Medicine/Division of Pain Medicine, Neurology and Psychology, and Consortium for Neuroengineering and Brain-Computer Interfaces, The University of Alabama at Birmingham, Birmingham, AL, United States
| | - Tony L. Yaksh
- Department of Anesthesiology, University of California San Diego, San Diego, CA, United States
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5
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Thurston LT, Skorska MN, Lobaugh NJ, Zucker KJ, Chakravarty MM, Lai MC, Chavez S, VanderLaan DP. White matter microstructure in transmasculine and cisgender adolescents: A multiparametric and multivariate study. PLoS One 2024; 19:e0300139. [PMID: 38470896 DOI: 10.1371/journal.pone.0300139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2023] [Accepted: 02/21/2024] [Indexed: 03/14/2024] Open
Abstract
Adolescence is a sensitive developmental period for neural sex/gender differentiation. The present study used multiparametric mapping to better characterize adolescent white matter (WM) microstructure. WM microstructure was investigated using diffusion tensor indices (fractional anisotropy; mean, radial, and axial diffusivity [AD]) and quantitative T1 relaxometry (T1) in hormone therapy naïve adolescent cisgender girls, cisgender boys, and transgender boys (i.e., assigned female at birth and diagnosed with gender dysphoria). Diffusion indices were first analyzed for group differences using tract-based spatial statistics, which revealed a group difference in AD. Thus, two multiparametric and multivariate analyses assessed AD in conjunction with T1 relaxation time, and with respect to developmental proxy variables (i.e., age, serum estradiol, pubertal development, sexual attraction) thought to be relevant to adolescent brain development. The multivariate analyses showed a shared pattern between AD and T1 such that higher AD was associated with longer T1, and AD and T1 strongly related to all five developmental variables in cisgender boys (10 significant correlations, r range: 0.21-0.73). There were fewer significant correlations between the brain and developmental variables in cisgender girls (three correlations, r range: -0.54-0.54) and transgender boys (two correlations, r range: -0.59-0.77). Specifically, AD related to direction of sexual attraction (i.e., gynephilia, androphilia) in all groups, and T1 related to estradiol inversely in cisgender boys compared with transgender boys. These brain patterns may be indicative of less myelination and tissue density in cisgender boys, which corroborates other reports of protracted WM development in cisgender boys. Further, these findings highlight the importance of considering developmental trajectory when assessing the subtleties of neural structure associated with variations in sex, gender, and sexual attraction.
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Affiliation(s)
- Lindsey T Thurston
- Department of Psychology, University of Toronto Mississauga, Mississauga, Ontario, Canada
| | - Malvina N Skorska
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Nancy J Lobaugh
- Brain Health Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
- Division of Neurology, Temerty Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Kenneth J Zucker
- Department of Psychiatry, Temerty Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - M Mallar Chakravarty
- Cerebral Imaging Centre, Douglas Mental Health University Institute, Montreal, Ontario, Canada
| | - Meng-Chuan Lai
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
- Department of Psychiatry, Temerty Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
- Department of Psychiatry, The Hospital for Sick Children, Toronto, Ontario, Canada
- Autism Research Centre, Department of Psychiatry, University of Cambridge, Cambridge, United Kingdom
| | - Sofia Chavez
- Brain Health Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Doug P VanderLaan
- Department of Psychology, University of Toronto Mississauga, Mississauga, Ontario, Canada
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
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6
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Arraiza Zabalegui M. After the trans brain: a critique of the neurobiological accounts of embodied trans* identities. HISTORY AND PHILOSOPHY OF THE LIFE SCIENCES 2024; 46:10. [PMID: 38305812 PMCID: PMC10837215 DOI: 10.1007/s40656-023-00602-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2023] [Accepted: 12/13/2023] [Indexed: 02/03/2024]
Abstract
This paper critically analyses three main neurobiological hypotheses on trans* identities: the neurobiological theory about the origin of gender dysphoria, the neurodevelopmental cortical hypothesis, and the alternative hypothesis of self-referential thinking and body perception. In this study I focus then the attention on three elements: the issue of (de)pathologisation, the idea of the trans brain, and the aetiology of trans* identities. While the neurobiological theory about the origin of gender dysphoria and the neurodevelopmental cortical hypothesis claim the existence of the trans brain, each offering its own neurobiological depiction, the hypothesis of self-referential thinking and body perception doesn't postulate a distinctive neurobiological trait for all trans* people. I problematize both portrayals of the trans brain departing from the findings and conceptualizations of the paradigm shifting brain mosaicism. Unlike the hypothesis of self-referential thinking and body perception that keeps the question of causation open, both the neurobiological theory about the origin of gender dysphoria and the neurodevelopmental cortical hypothesis situate the origin of trans* identities in the neurobiological domain. I challenge the biological deterministic framework in which this aetiology is inscribed from a dynamic processual entanglement perspective. Finally, concerning the issue of (de)pathologisation of trans* identities, an evolution can be seen in each of the hypothesis and among them, from the least to the most depathologising. However, I question their complete departure from a pathologising framework.
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Affiliation(s)
- Maite Arraiza Zabalegui
- Department of Philosophy, Universidad del País Vasco/Euskal Herriko Unibertsitatea (UPV/EHU), Donostia/San Sebastián, Spain.
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7
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Fernández R, Zubiaurre-Elorza L, Santisteban A, Ojeda N, Collet S, Kiyar M, T'Sjoen G, Mueller SC, Guillamon A, Pásaro E. CBLL1 is hypomethylated and correlates with cortical thickness in transgender men before gender affirming hormone treatment. Sci Rep 2023; 13:21609. [PMID: 38062063 PMCID: PMC10703770 DOI: 10.1038/s41598-023-48782-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Accepted: 11/30/2023] [Indexed: 12/18/2023] Open
Abstract
Gender identity refers to the consciousness of being a man, a woman or other condition. Although it is generally congruent with the sex assigned at birth, for some people it is not. If the incongruity is distressing, it is defined as gender dysphoria (GD). Here, we measured whole-genome DNA methylation by the Illumina © Infinium Human Methylation 850k array and reported its correlation with cortical thickness (CTh) in 22 transgender men (TM) experiencing GD versus 25 cisgender men (CM) and 28 cisgender women (CW). With respect to the methylation analysis, TM vs. CW showed significant differences in 35 CpGs, while 2155 CpGs were found when TM vs. CM were compared. With respect to correlation analysis, TM showed differences in methylation of CBLL1 and DLG1 genes that correlated with global and left hemisphere CTh. Both genes were hypomethylated in TM compared to the cisgender groups. Early onset TM showed a positive correlation between CBLL1 and several cortical regions in the frontal (left caudal middle frontal), temporal (right inferior temporal, left fusiform) and parietal cortices (left supramarginal and right paracentral). This is the first study relating CBLL1 methylation with CTh in transgender persons and supports a neurodevelopmental hypothesis of gender identity.
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Affiliation(s)
- Rosa Fernández
- Centro Interdisciplinar de Química E Bioloxía - CICA. Departamento de Psicología, Universidade da Coruña, Grupo DICOMOSA, Campus Elviña S/N, 15071, A Coruña, Spain.
- Instituto de Investigación Biomédica de A Coruña (INIBIC), 15071, Oza, A Coruña, Spain.
| | - Leire Zubiaurre-Elorza
- Departamento de Psicología, Facultad de Ciencias de la Salud, Universidad de Deusto, Bilbao, Spain
| | - Andrea Santisteban
- Centro Interdisciplinar de Química E Bioloxía - CICA. Departamento de Psicología, Universidade da Coruña, Grupo DICOMOSA, Campus Elviña S/N, 15071, A Coruña, Spain
| | - Natalia Ojeda
- Departamento de Psicología, Facultad de Ciencias de la Salud, Universidad de Deusto, Bilbao, Spain
| | - Sarah Collet
- Department of Endocrinology, Ghent University Hospital, 9000, Ghent, Belgium
| | - Meltem Kiyar
- Department of Experimental Clinical and Health Psychology, Ghent University, 9000, Ghent, Belgium
| | - Guy T'Sjoen
- Department of Endocrinology, Center for Sexology and Gender, Ghent University Hospital, 9000, Ghent, Belgium
| | - Sven C Mueller
- Department of Experimental Clinical and Health Psychology, Ghent University, 9000, Ghent, Belgium
| | - Antonio Guillamon
- Departamento de Psicobiología, Facultad de Psicología, Universidad Nacional de Educación a Distancia, 28040, Madrid, Spain.
| | - Eduardo Pásaro
- Centro Interdisciplinar de Química E Bioloxía - CICA. Departamento de Psicología, Universidade da Coruña, Grupo DICOMOSA, Campus Elviña S/N, 15071, A Coruña, Spain
- Instituto de Investigación Biomédica de A Coruña (INIBIC), 15071, Oza, A Coruña, Spain
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Collet S, Bhaduri S, Kiyar M, Van Den Eynde T, Guillamon A, T'Sjoen G, Mueller SC. Testosterone administration affects 1H-MRS metabolite spectra in transgender men. Psychoneuroendocrinology 2023; 156:106337. [PMID: 37536143 DOI: 10.1016/j.psyneuen.2023.106337] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 07/18/2023] [Accepted: 07/18/2023] [Indexed: 08/05/2023]
Abstract
BACKGROUND Recently, a variety of studies using different neuroimaging techniques attempted to identify the existence of a brain endophenotype in people with gender dysphoria (GD). However, despite mounting neuroimaging work, brain gender differences and effects of gender-affirming hormone therapy (GAHT) at the metabolite level remain understudied. METHODS Thirty-one transgender men (TM) before and after testosterone administration (7.7 months ± 3.5 months), relative to 30 cisgender men (CM) and 35 cisgender women (CW) underwent magnetic resonance spectroscopy (1H-MRS) at two time points. Two brain regions were assessed, i.e. the lateral parietal cortex and the amygdala/anterior hippocampus. Associated metabolites that were measured include N-acetyl aspartate (NAA), creatine (Cr), choline (Cho), glutamate and glutamine (Glx), myo-inositol (mI), glycine (Gly) and their respective ratios. RESULTS A critical time by group interaction revealed an effect of GAHT in the lateral parietal cortex of TM. MI+Gly/Cr ratios decreased upon initiation of GAHT. In addition, NAA/Cr and Cho/Cr ratios were lower in CW when compared to CM in the lateral parietal cortex. Glx levels and Glx/Cr ratios in TM differed from those in CW in the amygdala/anterior hippocampus. Interestingly, pubertal age of onset of gender dysphoria (i.e. GD) in TM differentially affected testosterone-mediated effects on Cr concentration and NAA/Cr ratios when compared to childhood and adult GD onset in the amygdala/anterior hippocampus. CONCLUSION This 1H-MRS study demonstrated that testosterone administration shifts mI+Gly/Cr ratios in the parietal cortex. In the amygdala/anterior hippocampus, modulation of metabolite concentrations by age of onset of GD is suggestive for a possible developmental trend.
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Affiliation(s)
- Sarah Collet
- Department of Endocrinology, Ghent University Hospital, Ghent, Belgium.
| | - Sourav Bhaduri
- Symbiosis Centre for Medical Image Analysis, Symbiosis International (Deemed University), Pune, India
| | - Meltem Kiyar
- Department of Experimental Clinical and Health Psychology, Ghent University, Belgium
| | | | - Antonio Guillamon
- Departamento de Psicobiología, Facultad de Psicología, Universidad Nacional de Educación a Distancia, Madrid, Spain
| | - Guy T'Sjoen
- Department of Endocrinology, Center for Sexology and Gender, Ghent University Hospital, Ghent, Belgium
| | - Sven C Mueller
- Department of Experimental Clinical and Health Psychology, Ghent University, Belgium
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9
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Chikani UN, Bisi-Onyemaechi AI, Onu JU, Nduagubam O, Mbanefo NR, Ohuche IO, Chime PU, T Onyia JO, Ogugua CF, Ugege MO. Dimensional approach to gender dysphoria in Nigeria: Association with socio-demographic and psycho-sexual variables. Niger J Clin Pract 2023; 26:1181-1191. [PMID: 37635615 DOI: 10.4103/njcp.njcp_124_23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/29/2023]
Abstract
Background Recent changes across the world with respect to gender transitioning of children and adolescents have generated a bio-psycho-socio-cultural discourse among interest groups. Aim This study sought to examine gender dysphoric symptoms among adolescents and young persons in an African population, using a dimensional approach. Method A total of 747 primary/secondary school and university students aged 10-24 years were studied using the 27-item Gender Identity/Gender Dysphoria Questionnaire for Adolescents and Adults (GIDYQ-AA). Participants were divided into early, mid- and late adolescents. The composite and domain scores were calculated using the criteria described by Deogracias, and comparison of the median scores was done using Mann-Whitney U-test and Kruskal-Wallis test as appropriate. Dunnett's post-hoc test was used for pairwise comparisons. Results The prevalence of self-identified transgender and self-reported non-heterosexuals was 0.9% (95%CI: 0.36-1.92) and 18.6% (15.85-21.59), respectively. The participants as a group scored 4.56 out of a possible 5 on the gender dysphoria scale, indicating less gender dysphoric symptoms in this cohort. However, participants in mid- and late adolescents had significantly lower scores when compared with early adolescents (P = 0.009). Self-reported transgender had significantly lower scores in the social (P = 0.001) and socio-legal (P < 0.001) indicators of the scale. Conclusion The findings of this study, although, preliminary demonstrated less gender dysphoric symptoms in this cohort of Nigerian adolescents and young adults compared to the Western population. Nevertheless, some degree of GD was noticed, revealing that this condition is existent in our society.
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Affiliation(s)
- U N Chikani
- Department of Paediatrics, Division of Paediatric Endocrinology, University of Nigeria Teaching Hospital, Ituku-Ozalla Campus, Enugu, Nigeria
| | - A I Bisi-Onyemaechi
- Department of Paediatrics, Division of Paediatric Neurology, University of Nigeria Teaching Hospital Ituku-Ozalla Campus, Enugu, Nigeria
| | - J U Onu
- Department of Mental Health, Nnamdi Azikiwe University, Awka, Anambra State and Honorary Consultant Psychiatrist, Federal Neuropsychiatric Hospital, Enugu, Nigeria
| | - O Nduagubam
- Department of Paediatrics, Enugu State Teaching Hospital, College of Medicine, Parklane, Enugu, Nigeria
| | - N R Mbanefo
- Department of Paediatrics, Division of Nephrology, University of Nigeria Teaching Hospital, Ituku- Ozalla Campus, Enugu, Nigeria
| | - I O Ohuche
- Department of Paediatrics, Division of Paediatric Endocrinology, University of Nigeria Teaching Hospital, Ituku-Ozalla Campus, Enugu, Nigeria
| | - P U Chime
- Department of Paediatrics, Division of Pulmonology, University of Nigeria Teaching Hospital, Ituku-Ozalla Campus, Enugu, Nigeria
| | - J O T Onyia
- Department of Paediatrics, Division of Gastroenterology, University of Nigeria, Ituku Ozalla Campus, Enugu, Nigeria
| | - C F Ogugua
- Department of Paediatrics, Division of Endocrinology, Alex Ekwueme Federal University Teaching Hospital Abakaliki, Abakaliki, Ebonyi, Nigeria
| | - M O Ugege
- Department of Paediatrics, College of Health Sciences, Usman Danfodiyo University/Usman Danfodiyo University Teaching, Hospital (UDUTH), Sokoto, Nigeria
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10
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Skorska MN, Thurston LT, Biasin JM, Devenyi GA, Zucker KJ, Chakravarty MM, Lai MC, VanderLaan DP. Cortical Structure Differences in Relation to Age, Sexual Attractions, and Gender Dysphoria in Adolescents: An Examination of Mean Diffusivity and T1 Relaxation Time. Brain Sci 2023; 13:963. [PMID: 37371441 PMCID: PMC10296103 DOI: 10.3390/brainsci13060963] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2023] [Revised: 06/08/2023] [Accepted: 06/13/2023] [Indexed: 06/29/2023] Open
Abstract
Recent research found that the combination of masculine gender identity and gynephilia was associated with cortical T1 relaxation time, which is considered to reflect gray matter density. We hypothesized that mean diffusivity (MD), a diffusion tensor imaging metric that reflects the degree to which water movement is free versus constrained, in combination with T1 relaxation time would provide further insight regarding cortical tissue characteristics. MD and T1 relaxation time were measured in 76 cortical regions in 15 adolescents assigned female at birth who experience gender dysphoria (GD AFAB) and were not receiving hormone therapy, 17 cisgender girls, and 14 cisgender boys (ages 12-17 years). Sexual orientation was represented by the degree of androphilia-gynephilia and the strength of sexual attraction. In multivariate analyses, cortical T1 relaxation time showed a weak but statistically significant positive association with MD across the cortex, suggesting that macromolecule-rich cortical tissue also tends to show water movement that is somewhat more constrained. In further multivariate analyses, in several left frontal, parietal, and temporal regions, the combination of shorter T1 relaxation time and faster MD was associated with older age and greater gynephilia in GD AFAB individuals and cisgender boys and with stronger attractions in cisgender boys only. Thus, for these cortical regions in these groups, older age, gynephilia, and stronger attractions (cisgender boys only) were associated with macromolecule-rich tissue in which water movement was freer-a pattern that some prior research suggests is associated with greater cell density and size. Overall, this study indicates that investigating T1 relaxation time and MD together can further inform how cortical gray matter tissue characteristics relate to age and psychosexuality.
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Affiliation(s)
- Malvina N. Skorska
- Child & Youth Psychiatry, Centre for Addiction and Mental Health, Toronto, ON M6J 1H4, Canada; (M.N.S.)
| | - Lindsey T. Thurston
- Department of Psychology, University of Toronto Mississauga, Mississauga, ON L5L 1C6, Canada
| | - Jessica M. Biasin
- Department of Psychology, University of Toronto Mississauga, Mississauga, ON L5L 1C6, Canada
| | - Gabriel A. Devenyi
- Cerebral Imaging Centre, Douglas Mental Health University Institute, Montreal, QC H4H 1R3, Canada (M.M.C.)
- Department of Psychiatry, McGill University, Montreal, QC H3A 1A1, Canada
| | - Kenneth J. Zucker
- Department of Psychiatry, Temerty Faculty of Medicine, University of Toronto, Toronto, ON M5T 1R8, Canada
| | - M. Mallar Chakravarty
- Cerebral Imaging Centre, Douglas Mental Health University Institute, Montreal, QC H4H 1R3, Canada (M.M.C.)
- Department of Psychiatry, McGill University, Montreal, QC H3A 1A1, Canada
- Department of Biological and Biomedical Engineering, McGill University, Montreal, QC H3A 2B4, Canada
| | - Meng-Chuan Lai
- Child & Youth Psychiatry, Centre for Addiction and Mental Health, Toronto, ON M6J 1H4, Canada; (M.N.S.)
- Department of Psychiatry, Temerty Faculty of Medicine, University of Toronto, Toronto, ON M5T 1R8, Canada
- The Margaret and Wallace McCain Centre for Child, Youth & Family Mental Health, Azrieli Adult Neurodevelopmental Centre, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON M6J 1H4, Canada
- Department of Psychiatry and Autism Research Unit, The Hospital for Sick Children, Toronto, ON M5G 1X8, Canada
- Autism Research Centre, Department of Psychiatry, University of Cambridge, Cambridge CB2 8AH, UK
- Department of Psychiatry, National Taiwan University Hospital and College of Medicine, Taipei 100229, Taiwan
| | - Doug P. VanderLaan
- Child & Youth Psychiatry, Centre for Addiction and Mental Health, Toronto, ON M6J 1H4, Canada; (M.N.S.)
- Department of Psychology, University of Toronto Mississauga, Mississauga, ON L5L 1C6, Canada
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11
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van Heesewijk J, Steenwijk MD, Kreukels BPC, Veltman DJ, Bakker J, Burke SM. Alterations in the inferior fronto-occipital fasciculus - a specific neural correlate of gender incongruence? Psychol Med 2023; 53:3461-3470. [PMID: 35301969 PMCID: PMC10277722 DOI: 10.1017/s0033291721005547] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 11/06/2021] [Accepted: 12/28/2021] [Indexed: 11/05/2022]
Abstract
BACKGROUND Increasing numbers of adolescents seek help for gender-identity questions. Consequently, requests for medical treatments, such as puberty suppression, are growing. However, studies investigating the neurobiological substrate of gender incongruence (when birth-assigned sex and gender identity do not align) are scarce, and knowledge about the effects of puberty suppression on the developing brain of transgender youth is limited. METHODS Here we cross-sectionally investigated sex and gender differences in regional fractional anisotropy (FA) as measured by diffusion MR imaging, and the impact of puberty on alterations in the white-matter organization of 35 treatment-naive prepubertal children and 41 adolescents with gender incongruence, receiving puberty suppression. The transgender groups were compared with 79 age-matched, treatment-naive cisgender (when sex and gender align) peers. RESULTS We found that transgender adolescents had lower FA in the bilateral inferior fronto-occipital fasciculus (IFOF), forceps major and corpus callosum than cisgender peers. In addition, average FA values of the right IFOF correlated negatively with adolescents' cumulative dosage of puberty suppressants received. Of note, prepubertal children also showed significant FA group differences in, again, the right IFOF and left cortico-spinal tract, but with the reverse pattern (transgender > cisgender) than was seen in adolescents. CONCLUSIONS Importantly, our results of lower FA (indexing less longitudinal organization, fiber coherence, and myelination) in the IFOF of gender-incongruent adolescents replicate prior findings in transgender adults, suggesting a salient neural correlate of gender incongruence. Findings highlight the complexity with which (pubertal) sex hormones impact white-matter development and add important insight into the neurobiological substrate associated with gender incongruence.
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Affiliation(s)
- Jason van Heesewijk
- Center of Expertise on Gender Dysphoria, Amsterdam University Medical Centers, location VUmc, De Boelelaan 1131, Amsterdam, Noord-Holland, Netherlands
| | - Martijn D. Steenwijk
- Center of Expertise on Gender Dysphoria, Amsterdam University Medical Centers, location VUmc, De Boelelaan 1131, Amsterdam, Noord-Holland, Netherlands
| | - Baudewijntje P. C. Kreukels
- Center of Expertise on Gender Dysphoria, Amsterdam University Medical Centers, location VUmc, De Boelelaan 1131, Amsterdam, Noord-Holland, Netherlands
| | - Dick J. Veltman
- Center of Expertise on Gender Dysphoria, Amsterdam University Medical Centers, location VUmc, De Boelelaan 1131, Amsterdam, Noord-Holland, Netherlands
| | - Julie Bakker
- Center of Expertise on Gender Dysphoria, Amsterdam University Medical Centers, location VUmc, De Boelelaan 1131, Amsterdam, Noord-Holland, Netherlands
| | - Sarah M. Burke
- Center of Expertise on Gender Dysphoria, Amsterdam University Medical Centers, location VUmc, De Boelelaan 1131, Amsterdam, Noord-Holland, Netherlands
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12
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Ballering AV, Burke SM, Maeckelberghe ELM, Rosmalen JGM. How to Ensure Inclusivity in Large-Scale General Population Cohort Studies? Lessons Learned with Regard to Including and Assessing Sex, Gender, and Sexual Orientation. ARCHIVES OF SEXUAL BEHAVIOR 2023:10.1007/s10508-023-02600-y. [PMID: 37186037 DOI: 10.1007/s10508-023-02600-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Revised: 04/04/2023] [Accepted: 04/05/2023] [Indexed: 05/17/2023]
Abstract
Despite recent advances in the measurement of sex, gender, and sexual orientation in large-scale cohort studies, the three concepts are still gaining relatively little attention, may be mistakenly equated, or non-informatively operationalized. The resulting imprecise or lacking information hereon in studies is problematic, as sex, gender, and sexual orientation are important health-related factors. Omission of these concepts from general population cohort studies might dismiss participants' identity and experiences and pushes research on sexual or gender minority populations toward purposive sampling, potentially introducing selection bias. It also reinforces the unintentional notion of irrelevance of these concepts to health research, ultimately disadvantaging sexual and gender minority populations. Similarly, a lack of uniform measures on sex, gender, and sexual orientation hampers multi-cohort studies in which data from multiple studies are combined, facilitating increased statistical power. This paper discusses the encountered pitfalls and lessons learned on including and assessing sex, gender, and sexual orientation in large-scale general population cohort studies, exemplified by the Dutch Lifelines Cohort Study. Additionally, we propose hands-on strategies on how to operationalize these concepts in an inclusive manner that is useful for large-scale general population cohort studies.
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Affiliation(s)
- Aranka V Ballering
- Department of Psychiatry, University Medical Center Groningen, University of Groningen, P.O. Box 30.001, 9700 RB, Groningen, The Netherlands.
| | - Sarah M Burke
- Department of Psychiatry, University Medical Center Groningen, University of Groningen, P.O. Box 30.001, 9700 RB, Groningen, The Netherlands
| | - Els L M Maeckelberghe
- University Medical Center Groningen, Wenckebach Institute for Training and Education, University of Groningen, Groningen, The Netherlands
| | - Judith G M Rosmalen
- Department of Psychiatry, University Medical Center Groningen, University of Groningen, P.O. Box 30.001, 9700 RB, Groningen, The Netherlands
- Department of Internal Medicine, University Medical Center of Groningen, University of Groningen, Groningen, The Netherlands
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13
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Kauffman RP, Guerra C, Thompson CM, Stark A. Concordance for Gender Dysphoria in Genetic Female Monozygotic (Identical) Triplets. ARCHIVES OF SEXUAL BEHAVIOR 2022; 51:3647-3651. [PMID: 36044128 DOI: 10.1007/s10508-022-02409-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 08/17/2022] [Accepted: 08/18/2022] [Indexed: 06/15/2023]
Abstract
The biopsychosocial etiology of gender dysphoria is poorly understood, but current thought suggests a complex interaction of genetic, hormonal, environmental, and differences in brain development and physiology. Twin studies have implicated a genetic role in the formation of gender identity. Congruence for gender dysphoria is more common among monozygotic twins compared to dizygotic twins. We present a case of monozygotic (identical) triplets who have each transitioned from female to male under the care of a university transgender health service. Each triplet experienced gender dysphoria from childhood and has undergone transitional endocrine care and various aspects of gender-affirming surgery. Although a pure genetic or biological component cannot be attributed as a cause of their gender dysphoria with absolute certainty since the triplets were raised together, this unusual case of gender dysphoria among a set of monozygotic triplets adds support for a heritable role in gender identity formation.
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Affiliation(s)
- Robert P Kauffman
- Department of Obstetrics and Gynecology, Texas Tech University Health Sciences Center School of Medicine, 1400 S. Coulter St., Amarillo, TX, 79106, USA.
| | - Carly Guerra
- Texas Tech University Health Sciences Center School of Medicine, Amarillo, TX, USA
| | | | - Amy Stark
- Department of Psychiatry, Texas Tech University Health Sciences Center School of Medicine, Amarillo, TX, USA
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14
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Transwoman Elite Athletes: Their Extra Percentage Relative to Female Physiology. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:ijerph19159103. [PMID: 35897465 PMCID: PMC9331831 DOI: 10.3390/ijerph19159103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Revised: 06/28/2022] [Accepted: 07/07/2022] [Indexed: 12/03/2022]
Abstract
There is increasing debate as to whether transwoman athletes should be included in the elite female competition. Most elite sports are divided into male and female divisions because of the greater athletic performance displayed by males. Without the sex division, females would have little chance of winning because males are faster, stronger, and have greater endurance capacity. Male physiology underpins their better athletic performance including increased muscle mass and strength, stronger bones, different skeletal structure, better adapted cardiorespiratory systems, and early developmental effects on brain networks that wires males to be inherently more competitive and aggressive. Testosterone secreted before birth, postnatally, and then after puberty is the major factor that drives these physiological sex differences, and as adults, testosterone levels are ten to fifteen times higher in males than females. The non-overlapping ranges of testosterone between the sexes has led sports regulators, such as the International Olympic Committee, to use 10 nmol/L testosterone as a sole physiological parameter to divide the male and female sporting divisions. Using testosterone levels as a basis for separating female and male elite athletes is arguably flawed. Male physiology cannot be reformatted by estrogen therapy in transwoman athletes because testosterone has driven permanent effects through early life exposure. This descriptive critical review discusses the inherent male physiological advantages that lead to superior athletic performance and then addresses how estrogen therapy fails to create a female-like physiology in the male. Ultimately, the former male physiology of transwoman athletes provides them with a physiological advantage over the cis-female athlete.
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15
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Skorska MN, Lobaugh NJ, Lombardo MV, van Bruggen N, Chavez S, Thurston LT, Aitken M, Zucker KJ, Chakravarty MM, Lai MC, VanderLaan DP. Inter-Network Brain Functional Connectivity in Adolescents Assigned Female at Birth Who Experience Gender Dysphoria. Front Endocrinol (Lausanne) 2022; 13:903058. [PMID: 35937791 PMCID: PMC9353716 DOI: 10.3389/fendo.2022.903058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Accepted: 06/15/2022] [Indexed: 11/13/2022] Open
Abstract
Gender dysphoria (GD) is characterized by distress due to an incongruence between experienced gender and sex assigned at birth. Brain functional connectivity in adolescents who experience GD may be associated with experienced gender (vs. assigned sex) and/or brain networks implicated in own-body perception. Furthermore, sexual orientation may be related to brain functional organization given commonalities in developmental mechanisms proposed to underpin GD and same-sex attractions. Here, we applied group independent component analysis to resting-state functional magnetic resonance imaging (rs-fMRI) BOLD timeseries data to estimate inter-network (i.e., between independent components) timeseries correlations, representing functional connectivity, in 17 GD adolescents assigned female at birth (AFAB) not receiving gender-affirming hormone therapy, 17 cisgender girls, and 15 cisgender boys (ages 12-17 years). Sexual orientation was represented by degree of androphilia-gynephilia and sexual attractions strength. Multivariate partial least squares analyses found that functional connectivity differed among cisgender boys, cisgender girls, and GD AFAB, with the largest difference between cisgender boys and GD AFAB. Regarding sexual orientation and age, the brain's intrinsic functional organization of GD AFAB was both similar to and different from cisgender girls, and both differed from cisgender boys. The pattern of group differences and the networks involved aligned with the hypothesis that brain functional organization is different among GD AFAB (vs. cisgender) adolescents, and certain aspects of this organization relate to brain areas implicated in own-body perception and self-referential thinking. Overall, brain functional organization of GD AFAB was generally more similar to that of cisgender girls than cisgender boys.
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Affiliation(s)
- Malvina N. Skorska
- Child and Youth Psychiatry, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Nancy J. Lobaugh
- Brain Health Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
- Department of Medicine, Division of Neurology, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Michael V. Lombardo
- Laboratory for Autism and Neurodevelopmental Disorders, Center for Neuroscience and Cognitive Systems @UniTn, Istituto Italiano di Tecnologia, Rovereto, Italy
| | - Nina van Bruggen
- Department of Psychology, University of Toronto Mississauga, Mississauga, ON, Canada
| | - Sofia Chavez
- Brain Health Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
- Department of Psychiatry, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Lindsey T. Thurston
- Department of Psychology, University of Toronto Mississauga, Mississauga, ON, Canada
| | - Madison Aitken
- Department of Psychiatry, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Kenneth J. Zucker
- Department of Psychiatry, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - M. Mallar Chakravarty
- Cerebral Imaging Centre, Douglas Mental Health University Institute, Montreal, PQ, Canada
- Department of Psychiatry, McGill University, Montreal, PQ, Canada
- Department of Biological and Biomedical Engineering, McGill University, Montreal, PQ, Canada
| | - Meng-Chuan Lai
- Child and Youth Psychiatry, Centre for Addiction and Mental Health, Toronto, ON, Canada
- Department of Psychiatry, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, Canada
- The Margaret and Wallace McCain Centre for Child, Youth & Family Mental Health and Azrieli Adult Neurodevelopmental Centre, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON, Canada
- Department of Psychiatry and Autism Research Unit, The Hospital for Sick Children, Toronto, ON, Canada
- Department of Psychiatry, National Taiwan University Hospital and College of Medicine, Taipei, Taiwan
- Autism Research Centre, Department of Psychiatry, University of Cambridge, Cambridge, United Kingdom
| | - Doug P. VanderLaan
- Child and Youth Psychiatry, Centre for Addiction and Mental Health, Toronto, ON, Canada
- Department of Psychology, University of Toronto Mississauga, Mississauga, ON, Canada
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16
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Uribe C, Escrichs A, de Filippi E, Sanz-Perl Y, Junque C, Gomez-Gil E, Kringelbach ML, Guillamon A, Deco G. Whole-brain dynamics differentiate among cisgender and transgender individuals. Hum Brain Mapp 2022; 43:4103-4115. [PMID: 35583382 PMCID: PMC9374880 DOI: 10.1002/hbm.25905] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2021] [Revised: 04/25/2022] [Accepted: 04/28/2022] [Indexed: 11/08/2022] Open
Abstract
How the brain represents gender identity is largely unknown, but some neural differences have recently been discovered. We used an intrinsic ignition framework to investigate whether there are gender differences in the propagation of neural activity across the whole-brain and within resting-state networks. Studying 29 trans men and 17 trans women with gender incongruence, 22 cis women, and 19 cis men, we computed the capability of a given brain area in space to propagate activity to other areas (mean-ignition), and the variability across time for each brain area (node-metastability). We found that both measurements differentiated all groups across the whole brain. At the network level, we found that compared to the other groups, cis men showed higher mean-ignition of the dorsal attention network and node-metastability of the dorsal and ventral attention, executive control, and temporal parietal networks. We also found higher mean-ignition values in cis men than in cis women within the executive control network, but higher mean-ignition in cis women than cis men and trans men for the default mode. Node-metastability was higher in cis men than cis women in the somatomotor network, while both mean-ignition and node-metastability were higher for cis men than trans men in the limbic network. Finally, we computed correlations between these measurements and a body image satisfaction score. Trans men's dissatisfaction as well as cis men's and cis women's satisfaction toward their own body image were distinctively associated with specific networks in each group. Overall, the study of the whole-brain network dynamical complexity discriminates gender identity groups, functional dynamic approaches could help disentangle the complex nature of the gender dimension in the brain.
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Affiliation(s)
- Carme Uribe
- Unitat de Psicologia Medica, Departament de Medicina, Institute of Neuroscience, Universitat de Barcelona, Barcelona, Spain.,Institute of Biomedical Research August Pi i Sunyer (IDIBAPS), Barcelona, Spain.,Research Imaging Centre, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health (CAMH), University of Toronto, Toronto, Canada
| | - Anira Escrichs
- Computational Neuroscience Group, Center for Brain and Cognition, Department of Information and Communication Technologies, Universitat Pompeu Fabra, Barcelona, Catalonia, Spain
| | - Eleonora de Filippi
- Computational Neuroscience Group, Center for Brain and Cognition, Department of Information and Communication Technologies, Universitat Pompeu Fabra, Barcelona, Catalonia, Spain
| | - Yonatan Sanz-Perl
- Computational Neuroscience Group, Center for Brain and Cognition, Department of Information and Communication Technologies, Universitat Pompeu Fabra, Barcelona, Catalonia, Spain
| | - Carme Junque
- Unitat de Psicologia Medica, Departament de Medicina, Institute of Neuroscience, Universitat de Barcelona, Barcelona, Spain.,Institute of Biomedical Research August Pi i Sunyer (IDIBAPS), Barcelona, Spain
| | | | - Morten L Kringelbach
- Department of Psychiatry, University of Oxford, Oxford, UK.,Centre for Eudaimonia and Human Flourishing, University of Oxford, Oxford, UK.,Center for Music in the Brain, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Antonio Guillamon
- Departamento de Psicobiologia, Facultad de Psicologia, Universidad Nacional de Educacion a Distancia, Madrid, Spain
| | - Gustavo Deco
- Computational Neuroscience Group, Center for Brain and Cognition, Department of Information and Communication Technologies, Universitat Pompeu Fabra, Barcelona, Catalonia, Spain.,Institució Catalana de la Recerca i Estudis Avançats (ICREA), Barcelona, Catalonia, Spain.,Department of Neuropsychology, Max Planck Institute for human Cognitive and Brain Sciences, Leipzig, Germany.,Turner Institute for Brain and Mental Health, Monash University, Melbourne, Victoria, Australia
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17
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Schuster V, Jansen A. 'That Time of the Month' - Investigating the Influence of the Menstrual Cycle and Oral Contraceptives on the Brain Using Magnetic Resonance Imaging. Exp Clin Endocrinol Diabetes 2022; 130:303-312. [PMID: 35605601 DOI: 10.1055/a-1816-8203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
The stereotypic and oversimplified relationship between female sex hormones and undesirable behavior dates to the earliest days of human society, as already the ancient Greek word for the uterus, "hystera" indicated an aversive connection. Remaining and evolving throughout the centuries, transcending across cultures and various aspects of everyday life, its perception was only recently reframed. Contemporarily, the complex interaction of hormonal phases (i. e., the menstrual cycle), hormonal medication (i. e., oral contraceptives), women's psychological well-being, and behavior is the subject of multifaceted and more reflected discussions. A driving force of this ongoing paradigm shift was the introduction of this highly interesting and important topic into the realm of scientific research. This refers to neuroscientific research as it enables a multimodal approach combining aspects of physiology, medicine, and psychology. Here a growing body of literature points towards significant alterations of both brain function, such as lateralization of cognitive functions, and structure, such as gray matter concentrations, due to fluctuations and changes in hormonal levels. This especially concerns female sex hormones. However, the more research is conducted within this field, the less reliable these observations and derived insights appear. This may be due to two particular factors: measurement inconsistencies and diverse hormonal phases accompanied by interindividual differences. The first factor refers to the prominent unreliability of one of the primarily utilized neuroscientific research instruments: functional magnetic resonance imaging (fMRI). This unreliability is seemingly present in paradigms and analyses, and their interplay, and is additionally affected by the second factor. In more detail, hormonal phases and levels further influence neuroscientific results obtained through fMRI as outcomes vary drastically across different cycle phases and medication. This resulting vast uncertainty thus tremendously hinders the further advancement of our understanding of how female sex hormones might alter brain structure and function and, ultimately, behavior.This review summarizes parts of the current state of research and outlines the essential requirements to further investigate and understand the female brain's underlying physiological and anatomical features.
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Affiliation(s)
- Verena Schuster
- Laboratory for Multimodal Neuroimaging, Department of Psychiatry and Psychotherapy, University of Marburg, Germany
| | - Andreas Jansen
- Laboratory for Multimodal Neuroimaging, Department of Psychiatry and Psychotherapy, University of Marburg, Germany.,Core-Unit Brainimaging, Faculty of Medicine, University of Marburg, Germany
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18
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Brain Sex in Transgender Women Is Shifted towards Gender Identity. J Clin Med 2022; 11:jcm11061582. [PMID: 35329908 PMCID: PMC8955456 DOI: 10.3390/jcm11061582] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2022] [Revised: 03/07/2022] [Accepted: 03/09/2022] [Indexed: 01/09/2023] Open
Abstract
Transgender people report discomfort with their birth sex and a strong identification with the opposite sex. The current study was designed to shed further light on the question of whether the brains of transgender people resemble their birth sex or their gender identity. For this purpose, we analyzed a sample of 24 cisgender men, 24 cisgender women, and 24 transgender women before gender-affirming hormone therapy. We employed a recently developed multivariate classifier that yields a continuous probabilistic (rather than a binary) estimate for brains to be male or female. The brains of transgender women ranged between cisgender men and cisgender women (albeit still closer to cisgender men), and the differences to both cisgender men and to cisgender women were significant (p = 0.016 and p < 0.001, respectively). These findings add support to the notion that the underlying brain anatomy in transgender people is shifted away from their biological sex towards their gender identity.
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19
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Jett S, Malviya N, Schelbaum E, Jang G, Jahan E, Clancy K, Hristov H, Pahlajani S, Niotis K, Loeb-Zeitlin S, Havryliuk Y, Isaacson R, Brinton RD, Mosconi L. Endogenous and Exogenous Estrogen Exposures: How Women's Reproductive Health Can Drive Brain Aging and Inform Alzheimer's Prevention. Front Aging Neurosci 2022; 14:831807. [PMID: 35356299 PMCID: PMC8959926 DOI: 10.3389/fnagi.2022.831807] [Citation(s) in RCA: 40] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Accepted: 02/07/2022] [Indexed: 01/14/2023] Open
Abstract
After advanced age, female sex is the major risk factor for late-onset Alzheimer's disease (AD), the most common cause of dementia affecting over 24 million people worldwide. The prevalence of AD is higher in women than in men, with postmenopausal women accounting for over 60% of all those affected. While most research has focused on gender-combined risk, emerging data indicate sex and gender differences in AD pathophysiology, onset, and progression, which may help account for the higher prevalence in women. Notably, AD-related brain changes develop during a 10-20 year prodromal phase originating in midlife, thus proximate with the hormonal transitions of endocrine aging characteristic of the menopause transition in women. Preclinical evidence for neuroprotective effects of gonadal sex steroid hormones, especially 17β-estradiol, strongly argue for associations between female fertility, reproductive history, and AD risk. The level of gonadal hormones to which the female brain is exposed changes considerably across the lifespan, with relevance to AD risk. However, the neurobiological consequences of hormonal fluctuations, as well as that of hormone therapies, are yet to be fully understood. Epidemiological studies have yielded contrasting results of protective, deleterious and null effects of estrogen exposure on dementia risk. In contrast, brain imaging studies provide encouraging evidence for positive associations between greater cumulative lifetime estrogen exposure and lower AD risk in women, whereas estrogen deprivation is associated with negative consequences on brain structure, function, and biochemistry. Herein, we review the existing literature and evaluate the strength of observed associations between female-specific reproductive health factors and AD risk in women, with a focus on the role of endogenous and exogenous estrogen exposures as a key underlying mechanism. Chief among these variables are reproductive lifespan, menopause status, type of menopause (spontaneous vs. induced), number of pregnancies, and exposure to hormonal therapy, including hormonal contraceptives, hormonal therapy for menopause, and anti-estrogen treatment. As aging is the greatest risk factor for AD followed by female sex, understanding sex-specific biological pathways through which reproductive history modulates brain aging is crucial to inform preventative and therapeutic strategies for AD.
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Affiliation(s)
- Steven Jett
- Department of Neurology, Weill Cornell Medical College, New York, NY, United States
| | - Niharika Malviya
- Department of Neurology, Weill Cornell Medical College, New York, NY, United States
| | - Eva Schelbaum
- Department of Neurology, Weill Cornell Medical College, New York, NY, United States
| | - Grace Jang
- Department of Neurology, Weill Cornell Medical College, New York, NY, United States
| | - Eva Jahan
- Department of Neurology, Weill Cornell Medical College, New York, NY, United States
| | - Katherine Clancy
- Department of Neurology, Weill Cornell Medical College, New York, NY, United States
| | - Hollie Hristov
- Department of Neurology, Weill Cornell Medical College, New York, NY, United States
| | - Silky Pahlajani
- Department of Neurology, Weill Cornell Medical College, New York, NY, United States
- Department of Radiology, Weill Cornell Medical College, New York, NY, United States
| | - Kellyann Niotis
- Department of Neurology, Weill Cornell Medical College, New York, NY, United States
| | - Susan Loeb-Zeitlin
- Department of Obstetrics and Gynecology, Weill Cornell Medical College, New York, NY, United States
| | - Yelena Havryliuk
- Department of Obstetrics and Gynecology, Weill Cornell Medical College, New York, NY, United States
| | - Richard Isaacson
- Department of Neurology, Weill Cornell Medical College, New York, NY, United States
| | - Roberta Diaz Brinton
- Department of Pharmacology, University of Arizona, Tucson, AZ, United States
- Department of Neurology, University of Arizona, Tucson, AZ, United States
| | - Lisa Mosconi
- Department of Neurology, Weill Cornell Medical College, New York, NY, United States
- Department of Radiology, Weill Cornell Medical College, New York, NY, United States
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20
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Bakker J. The role of steroid hormones in the sexual differentiation of the human brain. J Neuroendocrinol 2022; 34:e13050. [PMID: 34708466 DOI: 10.1111/jne.13050] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 09/03/2021] [Accepted: 10/05/2021] [Indexed: 12/31/2022]
Abstract
Widespread sex differences in human brain structure and function have been reported. Research on animal models has demonstrated that sex differences in brain and behavior are induced by steroid hormones during specific, hormone sensitive, developmental periods. It was shown that typical male neural and behavioral characteristics develop under the influence of testosterone, mostly acting during perinatal development. By contrast, typical female neural and behavioral characteristics may actually develop under the influence of estradiol during a specific prepubertal period. This review provides an overview of our current knowledge on the role of steroid hormones in the sexual differentiation of the human brain. Both clinical and neuroimaging data obtained in patients with altered androgen levels/actions (i.e., congenital adrenal hyperplasia or complete androgen insensitivity syndrome [CAIS]), point to an important role of (prenatal) androgens in inducing typical male neural and psychosexual characteristics in humans. In contrast to rodents, there appears to be no obvious role for estrogens in masculinizing the human brain. Furthermore, data from CAIS also suggest a contribution of sex chromosome genes to the development of the human brain. The final part of this review is dedicated to a brief discussion of gender incongruence, also known as gender dysphoria, which has been associated with an altered or less pronounced sexual differentiation of the brain.
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Affiliation(s)
- Julie Bakker
- Neuroendocrinology, GIGA Neurosciences, Liège University, Liege, Belgium
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21
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Zubiaurre-Elorza L, Cerdán S, Uribe C, Pérez-Laso C, Marcos A, Rodríguez del Cerro MC, Fernandez R, Pásaro E, Guillamon A. The Effects of Testosterone on the Brain of Transgender Men. ANDROGENS: CLINICAL RESEARCH AND THERAPEUTICS 2021; 2:252-260. [PMID: 35024694 PMCID: PMC8744429 DOI: 10.1089/andro.2021.0008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Accepted: 07/21/2021] [Indexed: 01/28/2023]
Abstract
Transgender men (TM) experience an incongruence between the female sex assigned when they were born and their self-perceived male identity. Some TM seek for a gender affirming hormone treatment (GAHT) to induce a somatic transition from female to male through continuous administration of testosterone. GAHT seems to be relatively safe. However, testosterone produces structural changes in the brain as detected by quantitative magnetic resonance imaging. Mainly, it induces an increase in cortical volume and thickness and subcortical structural volume probably due to the anabolic effects. Animal models, specifically developed to test the anabolic hypothesis, suggest that testosterone and estradiol, its aromatized metabolite, participate in the control of astrocyte water trafficking, thereby controlling brain volume.
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Affiliation(s)
- Leire Zubiaurre-Elorza
- Department of Methods and Experimental Psychology, Faculty of Psychology and Education, University of Deusto, Bilbao, Spain
| | - Sebastian Cerdán
- Instituto de Investigaciones Biomédicas Alberto Sols, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Carme Uribe
- Institute of Neuroscience, University of Barcelona, Barcelona, Spain
| | - Carmen Pérez-Laso
- Departamento de Psicobiología, Universidad Nacional de Educación a Distancia, Madrid, Spain
| | - Alberto Marcos
- Departamento de Psicobiología, Universidad Nacional de Educación a Distancia, Madrid, Spain
| | | | - Rosa Fernandez
- Departamento de Psicología, Facultade de Ciencias da Educación, Universidade da Coruña, A Coruña, Spain
| | - Eduardo Pásaro
- Departamento de Psicología, Facultade de Ciencias da Educación, Universidade da Coruña, A Coruña, Spain
| | - Antonio Guillamon
- Departamento de Psicobiología, Universidad Nacional de Educación a Distancia, Madrid, Spain
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22
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Frigerio A, Ballerini L, Valdés Hernández M. Structural, Functional, and Metabolic Brain Differences as a Function of Gender Identity or Sexual Orientation: A Systematic Review of the Human Neuroimaging Literature. ARCHIVES OF SEXUAL BEHAVIOR 2021; 50:3329-3352. [PMID: 33956296 PMCID: PMC8604863 DOI: 10.1007/s10508-021-02005-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 04/06/2021] [Accepted: 04/08/2021] [Indexed: 05/05/2023]
Abstract
This review systematically explored structural, functional, and metabolic features of the cisgender brain compared with the transgender brain before hormonal treatment and the heterosexual brain compared to the homosexual brain from the analysis of the neuroimaging literature up to 2018, and identified and discussed subsequent studies published up to March 2021. Our main aim was to help identifying neuroradiological brain features that have been related to human sexuality to contribute to the understanding of the biological elements involved in gender identity and sexual orientation. We analyzed 39 studies on gender identity and 24 on sexual orientation. Our results suggest that some neuroanatomical, neurophysiological, and neurometabolic features in transgender individuals resemble those of their experienced gender despite the majority resembling those from their natal sex. In homosexual individuals the majority resemble those of their same-sex heterosexual population rather than their opposite-sex heterosexual population. However, it is always difficult to interpret findings with noninvasive neuroimaging. Given the gross nature of these measures, it is possible that more differences too subtle to measure with available tools yet contributing to gender identity and sexual orientation could be found. Conflicting results contributed to the difficulty of identifying specific brain features which consistently differ between cisgender and transgender or between heterosexual and homosexual groups. The small number of studies, the small-to-moderate sample size of each study, and the heterogeneity of the investigations made it impossible to meta-analyze all the data extracted. Further studies are necessary to increase the understanding of the neurological substrates of human sexuality.
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Affiliation(s)
- Alberto Frigerio
- Division of Health Sciences, University of Edinburgh, Edinburgh, EH16 4SB, UK
| | - Lucia Ballerini
- Division of Health Sciences, University of Edinburgh, Edinburgh, EH16 4SB, UK
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23
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Brain connectivity dynamics in cisgender and transmen people with gender incongruence before gender affirmative hormone treatment. Sci Rep 2021; 11:21036. [PMID: 34702875 PMCID: PMC8548343 DOI: 10.1038/s41598-021-00508-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 10/13/2021] [Indexed: 11/08/2022] Open
Abstract
Large-scale brain network interactions have been described between trans- and cis-gender binary identities. However, a temporal perspective of the brain's spontaneous fluctuations is missing. We investigated the functional connectivity dynamics in transmen with gender incongruence and its relationship with interoceptive awareness. We describe four states in native and meta-state spaces: (i) one state highly prevalent with sparse overall connections; (ii) a second with strong couplings mainly involving components of the salience, default, and executive control networks. Two states with global sparse connectivity but positive couplings (iii) within the sensorimotor network, and (iv) between salience network regions. Transmen had more dynamical fluidity than cismen, while cismen presented less meta-state fluidity and range dynamism than transmen and ciswomen. A positive association between attention regulation and fluidity and meta-state range dynamism was found in transmen. There exist gender differences in the temporal brain dynamism, characterized by distinct interrelations of the salience network as catalyst interacting with other networks. We offer a functional explanation from the neurodevelopmental cortical hypothesis of a gendered-self.
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24
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Ramirez K, Fernández R, Collet S, Kiyar M, Delgado-Zayas E, Gómez-Gil E, Van Den Eynde T, T'Sjoen G, Guillamon A, Mueller SC, Pásaro E. Epigenetics Is Implicated in the Basis of Gender Incongruence: An Epigenome-Wide Association Analysis. Front Neurosci 2021; 15:701017. [PMID: 34489625 PMCID: PMC8418298 DOI: 10.3389/fnins.2021.701017] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Accepted: 07/30/2021] [Indexed: 11/13/2022] Open
Abstract
Introduction The main objective was to carry out a global DNA methylation analysis in a population with gender incongruence before gender-affirming hormone treatment (GAHT), in comparison to a cisgender population. Methods A global CpG (cytosine-phosphate-guanine) methylation analysis was performed on blood from 16 transgender people before GAHT vs. 16 cisgender people using the Illumina© Infinium Human Methylation 850k BeadChip, after bisulfite conversion. Changes in the DNA methylome in cisgender vs. transgender populations were analyzed with the Partek® Genomics Suite program by a 2-way ANOVA test comparing populations by group and their sex assigned at birth. Results The principal components analysis (PCA) showed that both populations (cis and trans) differ in the degree of global CpG methylation prior to GAHT. The 2-way ANOVA test showed 71,515 CpGs that passed the criterion FDR p < 0.05. Subsequently, in male assigned at birth population we found 87 CpGs that passed both criteria (FDR p < 0.05; fold change ≥ ± 2) of which 22 were located in islands. The most significant CpGs were related to genes: WDR45B, SLC6A20, NHLH1, PLEKHA5, UBALD1, SLC37A1, ARL6IP1, GRASP, and NCOA6. Regarding the female assigned at birth populations, we found 2 CpGs that passed both criteria (FDR p < 0.05; fold change ≥ ± 2), but none were located in islands. One of these CpGs, related to the MPPED2 gene, is shared by both, trans men and trans women. The enrichment analysis showed that these genes are involved in functions such as negative regulation of gene expression (GO:0010629), central nervous system development (GO:0007417), brain development (GO:0007420), ribonucleotide binding (GO:0032553), and RNA binding (GO:0003723), among others. Strengths and Limitations It is the first time that a global CpG methylation analysis has been carried out in a population with gender incongruence before GAHT. A prospective study before/during GAHT would provide a better understanding of the influence of epigenetics in this process. Conclusion The main finding of this study is that the cis and trans populations have different global CpG methylation profiles prior to GAHT. Therefore, our results suggest that epigenetics may be involved in the etiology of gender incongruence.
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Affiliation(s)
- Karla Ramirez
- Laboratory of Psychobiology, Department of Psychology, Institute Advanced Scientific Research Center (CICA), University of A Coruña, A Coruña, Spain.,Laboratory of Neurophysiology, Center for Biophysics and Biochemistry, Venezuelan Institute for Scientific Research (IVIC), Caracas, Venezuela
| | - Rosa Fernández
- Laboratory of Psychobiology, Department of Psychology, Institute Advanced Scientific Research Center (CICA), University of A Coruña, A Coruña, Spain
| | - Sarah Collet
- Department of Endocrinology, Ghent University, Ghent, Belgium
| | - Meltem Kiyar
- Department of Experimental Clinical and Health Psychology, Ghent University, Ghent, Belgium
| | - Enrique Delgado-Zayas
- Laboratory of Psychobiology, Department of Psychology, Institute Advanced Scientific Research Center (CICA), University of A Coruña, A Coruña, Spain
| | | | | | - Guy T'Sjoen
- Department of Endocrinology, Ghent University, Ghent, Belgium
| | - Antonio Guillamon
- Department of Psychobiology, Faculty of Psychology, National University of Distance Education (UNED), Madrid, Spain
| | - Sven C Mueller
- Department of Experimental Clinical and Health Psychology, Ghent University, Ghent, Belgium
| | - Eduardo Pásaro
- Laboratory of Psychobiology, Department of Psychology, Institute Advanced Scientific Research Center (CICA), University of A Coruña, A Coruña, Spain
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25
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Collet S, Bhaduri S, Kiyar M, T’Sjoen G, Mueller S, Guillamon A. Characterization of the 1H-MRS Metabolite Spectra in Transgender Men with Gender Dysphoria and Cisgender People. J Clin Med 2021; 10:2623. [PMID: 34198690 PMCID: PMC8232168 DOI: 10.3390/jcm10122623] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Revised: 06/07/2021] [Accepted: 06/10/2021] [Indexed: 11/29/2022] Open
Abstract
Much research has been conducted on sexual differences of the human brain to determine whether and to what extent a brain gender exists. Consequently, a variety of studies using different neuroimaging techniques attempted to identify the existence of a brain phenotype in people with gender dysphoria (GD). However, to date, brain sexual differences at the metabolite level using magnetic resonance spectroscopy (1H-MRS) have not been explored in transgender people. In this study, 28 cisgender men (CM) and 34 cisgender women (CW) and 29 transgender men with GD (TMGD) underwent 1H-MRS at 3 Tesla MRI to characterize common brain metabolites. Specifically, levels of N-acetyl aspartate (NAA), choline (Cho), creatine (Cr), glutamate and glutamine (Glx), and myo-inositol + glycine (mI + Gly) were assessed in two brain regions, the amygdala-anterior hippocampus and the lateral parietal cortex. The results indicated a sex-assigned at birth pattern for Cho/Cr in the amygdala of TMGD. In the parietal cortex, a sex-assigned at birth and an intermediate pattern were found. Though assessed post-hoc, exploration of the age of onset of GD in TMGD demonstrated within-group differences in absolute NAA and relative Cho/Cr levels, suggestive for a possible developmental trend. While brain metabolite levels in TMGD resembled those of CW, some interesting findings, such as modulation of metabolite concentrations by age of onset of GD, warrant future inquiry.
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Affiliation(s)
- Sarah Collet
- Department of Endocrinology, Ghent University Hospital, 9000 Ghent, Belgium
| | - Sourav Bhaduri
- Department of Experimental Clinical and Health Psychology, Ghent University, 9000 Ghent, Belgium; (S.B.); (M.K.); (S.M.)
| | - Meltem Kiyar
- Department of Experimental Clinical and Health Psychology, Ghent University, 9000 Ghent, Belgium; (S.B.); (M.K.); (S.M.)
| | - Guy T’Sjoen
- Department of Endocrinology, Center for Sexology and Gender, Ghent University Hospital, 9000 Ghent, Belgium;
| | - Sven Mueller
- Department of Experimental Clinical and Health Psychology, Ghent University, 9000 Ghent, Belgium; (S.B.); (M.K.); (S.M.)
- Department of Personality, Psychological Assessment and Treatment, University of Deusto, 48007 Bilbao, Spain
| | - Antonio Guillamon
- Departamento de Psicobiología, Facultad de Psicología, Universidad Nacional de Educación a Distancia, 28040 Madrid, Spain;
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26
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Wang Y, Khorashad BS, Feusner JD, Savic I. Cortical Gyrification in Transgender Individuals. Cereb Cortex 2021; 31:3184-3193. [PMID: 33718960 PMCID: PMC8324983 DOI: 10.1093/cercor/bhaa412] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 12/20/2020] [Accepted: 12/23/2020] [Indexed: 12/26/2022] Open
Abstract
Gender incongruence (GI) is characterized by a feeling of estrangement from the own body in the context of self. GI is often described in people who identify as transgender. The underlying mechanisms are unknown. Data from MRI measurements and tests of own body perception triggered us to pose a model that GI in transgender persons (TGI) could be associated with a disconnection within the brain circuits mediating the perception of own body as self. This is a departure from a previous model of sex atypical cerebral dimorphism, introducing a concept that better accords with a core feature of TGI. The present MRI study of 54 hormone naive transmen (TrM), 38 transwomen (TrW), 44 cismen and 41 ciswomen show that cortical gyrification, a metric that reflects early maturation of cerebral cortex, is significantly lower in transgender compared with cisgender participants. This reduction is limited to the occipito-parietal cortex and the sensory motor cortex, regions encoding own body image and body ownership. Moreover, the cortical gyrification correlated inversely with own body-self incongruence in these regions. These novel data suggest that GI in TGI may originate in the neurodevelopment of body image encoding regions. The results add potentially to understanding neurobiological contributors to gender identity.
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Affiliation(s)
- Yanlu Wang
- Department of Clinical Science, Intervention and Technology, Karolinska Institute, Stockholm 171 77, Sweden
- MR Physics, Medical Radiation Physics and Nuclear Medicine, Karolinska University Hospital, Stockholm 171 76, Sweden
| | - Behzad S Khorashad
- Department of Women’s and Children’s Health, Karolinska Institutet, Stockholm 171 77, Sweden
| | - Jamie D Feusner
- Department of Women’s and Children’s Health, Karolinska Institutet, Stockholm 171 77, Sweden
- Semel Institute for Neuroscience and Human Behavior, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Ivanka Savic
- Department of Women’s and Children’s Health, Karolinska Institutet, Stockholm 171 77, Sweden
- Department of Neurology, University of California Los Angeles, Los Angeles, CA 90095-6975, USA
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27
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Baldinger-Melich P, Urquijo Castro MF, Seiger R, Ruef A, Dwyer DB, Kranz GS, Klöbl M, Kambeitz J, Kaufmann U, Windischberger C, Kasper S, Falkai P, Lanzenberger R, Koutsouleris N. Sex Matters: A Multivariate Pattern Analysis of Sex- and Gender-Related Neuroanatomical Differences in Cis- and Transgender Individuals Using Structural Magnetic Resonance Imaging. Cereb Cortex 2021; 30:1345-1356. [PMID: 31368487 PMCID: PMC7132951 DOI: 10.1093/cercor/bhz170] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Revised: 06/28/2019] [Accepted: 06/28/2019] [Indexed: 12/22/2022] Open
Abstract
Univariate analyses of structural neuroimaging data have produced heterogeneous results regarding anatomical sex- and gender-related differences. The current study aimed at delineating and cross-validating brain volumetric surrogates of sex and gender by comparing the structural magnetic resonance imaging data of cis- and transgender subjects using multivariate pattern analysis. Gray matter (GM) tissue maps of 29 transgender men, 23 transgender women, 35 cisgender women, and 34 cisgender men were created using voxel-based morphometry and analyzed using support vector classification. Generalizability of the models was estimated using repeated nested cross-validation. For external validation, significant models were applied to hormone-treated transgender subjects (n = 32) and individuals diagnosed with depression (n = 27). Sex was identified with a balanced accuracy (BAC) of 82.6% (false discovery rate [pFDR] < 0.001) in cisgender, but only with 67.5% (pFDR = 0.04) in transgender participants indicating differences in the neuroanatomical patterns associated with sex in transgender despite the major effect of sex on GM volume irrespective of the self-identification as a woman or man. Gender identity and gender incongruence could not be reliably identified (all pFDR > 0.05). The neuroanatomical signature of sex in cisgender did not interact with depressive features (BAC = 74.7%) but was affected by hormone therapy when applied in transgender women (P < 0.001).
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Affiliation(s)
- Pia Baldinger-Melich
- Department of Psychiatry and Psychotherapy, Clinical Division of General Psychiatry, Medical University of Vienna, Vienna, Austria.,Neuroimaging Labs (NIL) PET, MRI, EEG, TMS and Chemical Lab, Department of Psychiatry and Psychotherapy, Clinical Division of General Psychiatry, Medical University of Vienna, Vienna, Austria
| | - Maria F Urquijo Castro
- Department of Psychiatry and Psychotherapy, Ludwig-Maximilians-University, Munich, Bavaria, Germany.,Section for Neurodiagnostic Applications, Department of Psychiatry and Psychotherapy, Ludwig-Maximilians-University, Munich, Bavaria, Germany
| | - René Seiger
- Department of Psychiatry and Psychotherapy, Clinical Division of General Psychiatry, Medical University of Vienna, Vienna, Austria.,Neuroimaging Labs (NIL) PET, MRI, EEG, TMS and Chemical Lab, Department of Psychiatry and Psychotherapy, Clinical Division of General Psychiatry, Medical University of Vienna, Vienna, Austria
| | - Anne Ruef
- Department of Psychiatry and Psychotherapy, Ludwig-Maximilians-University, Munich, Bavaria, Germany.,Section for Neurodiagnostic Applications, Department of Psychiatry and Psychotherapy, Ludwig-Maximilians-University, Munich, Bavaria, Germany
| | - Dominic B Dwyer
- Department of Psychiatry and Psychotherapy, Ludwig-Maximilians-University, Munich, Bavaria, Germany.,Section for Neurodiagnostic Applications, Department of Psychiatry and Psychotherapy, Ludwig-Maximilians-University, Munich, Bavaria, Germany
| | - Georg S Kranz
- Department of Psychiatry and Psychotherapy, Clinical Division of General Psychiatry, Medical University of Vienna, Vienna, Austria.,Neuroimaging Labs (NIL) PET, MRI, EEG, TMS and Chemical Lab, Department of Psychiatry and Psychotherapy, Clinical Division of General Psychiatry, Medical University of Vienna, Vienna, Austria.,Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
| | - Manfred Klöbl
- Department of Psychiatry and Psychotherapy, Clinical Division of General Psychiatry, Medical University of Vienna, Vienna, Austria
| | - Joseph Kambeitz
- Department of Psychiatry and Psychotherapy, Ludwig-Maximilians-University, Munich, Bavaria, Germany.,Section for Neurodiagnostic Applications, Department of Psychiatry and Psychotherapy, Ludwig-Maximilians-University, Munich, Bavaria, Germany
| | - Ulrike Kaufmann
- Department of Obstetrics and Gynecology, Medical University of Vienna, Vienna, Austria
| | - Christian Windischberger
- MR Centre of Excellence, Centre for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Siegfried Kasper
- Department of Psychiatry and Psychotherapy, Clinical Division of General Psychiatry, Medical University of Vienna, Vienna, Austria
| | - Peter Falkai
- Department of Psychiatry and Psychotherapy, Ludwig-Maximilians-University, Munich, Bavaria, Germany
| | - Rupert Lanzenberger
- Department of Psychiatry and Psychotherapy, Clinical Division of General Psychiatry, Medical University of Vienna, Vienna, Austria.,Neuroimaging Labs (NIL) PET, MRI, EEG, TMS and Chemical Lab, Department of Psychiatry and Psychotherapy, Clinical Division of General Psychiatry, Medical University of Vienna, Vienna, Austria
| | - Nikolaos Koutsouleris
- Department of Psychiatry and Psychotherapy, Ludwig-Maximilians-University, Munich, Bavaria, Germany.,Section for Neurodiagnostic Applications, Department of Psychiatry and Psychotherapy, Ludwig-Maximilians-University, Munich, Bavaria, Germany
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28
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Venkataramu VN, Banerjee D. Gender Dysphoria in Psychiatric Practice: Understanding the Clinical Ambiguity and Management. JOURNAL OF PSYCHOSEXUAL HEALTH 2021. [DOI: 10.1177/26318318211017049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
There have been several myths and misconceptions about the dichotomous understanding of sex and gender. While sex is biologically determined, gender and gender identity depend on childhood experiences, upbringing, social expectations, beliefs, family environment, and peer interactions and is socially constructed. Gender dysphoria (GD) is the extreme distress experienced by an individual because of a mismatch between their gender identity and the sex assigned at birth. GD has been an ambiguous category in psychiatry, initially termed as “gender identity disorder” till Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition ( DSM-5) considered removal of the term “disorder” to reduce the stigma associated. The critical element in GD is “clinically significant distress” that differentiates it from gender nonconformity. Individuals with GD identify themselves as transgender and frequently are victims of coercive social norms, discrimination, and stigma. This leads to delay in expression of distress, psychiatric mismanagement, and high comorbidity of depression, anxiety, post-traumatic stress, self-harm, and suicidality. Though management involves a holistic multidisciplinary approach including psychotherapy, social support, and gender-reassignment treatments (medical/surgical), there has been considerable debate and ambiguity related to the same. With this background, the article critics the understanding of GD, focuses on the WPATH SOC-7 treatment guidelines, and highlights the role of mental health professionals for better care.
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Affiliation(s)
| | - Debanjan Banerjee
- Department of Psychiatry, National Institute of Mental Health and Neurosciences (NIMHANS), Bengaluru, Karnataka, India
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29
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Ramírez KDV, Fernández R, Delgado-Zayas E, Gómez-Gil E, Esteva I, Guillamon A, Pásaro E. Implications of the Estrogen Receptor Coactivators SRC1 and SRC2 in the Biological Basis of Gender Incongruence. Sex Med 2021; 9:100368. [PMID: 34049263 PMCID: PMC8240342 DOI: 10.1016/j.esxm.2021.100368] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 03/19/2021] [Accepted: 03/30/2021] [Indexed: 12/19/2022] Open
Abstract
Introduction Brain sexual differentiation results from the effects of sex steroids on the developing brain. The presumptive route for brain masculinization is the direct induction of gene expression via activation of the estrogen receptors α and β and the androgen receptor through their binding to ligands and to coactivators, regulating the transcription of multiple genes in a cascade effect. Aim To analyze the implication of the estrogen receptor coactivators SRC-1, SRC-2, and SRC-3 in the genetic basis of gender incongruence. Main Outcome Measures Analysis of 157 polymorphisms located at the estrogen receptor coactivators SRC-1, SRC-2, and SRC-3, in 94 transgender versus 94 cisgender individuals. Method Using SNPStats software, the allele and genotype frequencies were analyzed by χ2, the strength of the association was measured by binary logistic regression, estimating the odds ratio for each genotype. Measurements of linkage disequilibrium and haplotype frequencies were also performed. Results We found significant differences at level P < .05 in 8 polymorphisms that correspond to 5.09% of the total. Three were located in SRC-1 and 5 in SRC-2. The odds ratio analysis showed significant differences at level P < .05 for multiple patterns of inheritance. The polymorphisms analyzed were in linkage disequilibrium. The SRC-1 haplotypes CGA and CGG (global haplotype association P < .009) and the SRC-2 haplotypes GGTAA and GGTAG (global haplotype association P < .005) were overrepresented in the transgender population. Conclusion The coactivators SRC-1 and SRC-2 could be considered as candidates for increasing the list of potential genes for gender incongruence. Ramírez KDV, Fernández R, Delgado-Zayas E, et al. Implications of the Estrogen Receptor Coactivators SRC1 and SRC2 in the Biological Basis of Gender Incongruence. Sex Med 2021;9:100368.
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Affiliation(s)
- Karla Del Valle Ramírez
- Centro de Investigaciones Científicas Avanzadas (CICA), Departamento de Psicología. Universidade da Coruña (UDC), Coruña, Spain; Instituto de Investigación Biomédica de A Coruña (INIBIC), Coruña, Spain
| | - Rosa Fernández
- Centro de Investigaciones Científicas Avanzadas (CICA), Departamento de Psicología. Universidade da Coruña (UDC), Coruña, Spain; Instituto de Investigación Biomédica de A Coruña (INIBIC), Coruña, Spain.
| | - Enrique Delgado-Zayas
- Centro de Investigaciones Científicas Avanzadas (CICA), Departamento de Psicología. Universidade da Coruña (UDC), Coruña, Spain; Instituto de Investigación Biomédica de A Coruña (INIBIC), Coruña, Spain
| | - Esther Gómez-Gil
- Unidad de Identidad de Género, Instituto de Neurociencias, Hospital Clínic, Barcelona, Spain
| | - Isabel Esteva
- Servicio de Endocrinología y Nutrición, Unidad de Identidad de Género del Hospital Regional Universitario de Málaga, Spain
| | - Antonio Guillamon
- Departamento de Psicobiología, Universidad Nacional de Educación a Distancia, Madrid, Spain
| | - Eduardo Pásaro
- Centro de Investigaciones Científicas Avanzadas (CICA), Departamento de Psicología. Universidade da Coruña (UDC), Coruña, Spain; Instituto de Investigación Biomédica de A Coruña (INIBIC), Coruña, Spain
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Gender Identity Disorders: Current Medical and Social Paradigm and the ICD-11 Innovations. CONSORTIUM PSYCHIATRICUM 2021. [DOI: 10.17816/cp68] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Introduction. This article presents a review of current concepts of gender identity under normal and pathological conditions.
Aim. To analyse the impact of the medical and social paradigm shift for clinical practice.
Results and discussion. The modern academic literature devoted to gender identity disorders is characterized by a variety of terminology, a shift in emphasis from clinical judgement to a socially beneficial normocentric approach and a relatively few advanced, evidence-based research. There is also a lack of evidence for the gender theory underlying the new approach, which raises serious doubts about the validity of the medical and social paradigm revision. In the same time, the position of Russian psychiatrists remains to be more clinically oriented.
Conclusion. Patients who declare the desire to reassign their gender have to be assessed by psychiatrists for differential diagnosis to exclude a mental disorder. In such cases, the destigmatization of mental disorders is more critical than the depathologization of gender identity disorders.
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Mueller SC, Guillamon A, Zubiaurre-Elorza L, Junque C, Gomez-Gil E, Uribe C, Khorashad BS, Khazai B, Talaei A, Habel U, Votinov M, Derntl B, Lanzenberger R, Seiger R, Kranz GS, Kreukels BPC, Kettenis PTC, Burke SM, Lambalk NB, Veltman DJ, Kennis M, Sánchez FJ, Vilain E, Fisher AD, Mascalchi M, Gavazzi G, Orsolini S, Ristori J, Dannlowski U, Grotegerd D, Konrad C, Schneider MA, T'Sjoen G, Luders E. The Neuroanatomy of Transgender Identity: Mega-Analytic Findings From the ENIGMA Transgender Persons Working Group. J Sex Med 2021; 18:1122-1129. [PMID: 37057468 DOI: 10.1016/j.jsxm.2021.03.079] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 02/22/2021] [Accepted: 03/24/2021] [Indexed: 12/23/2022]
Abstract
BACKGROUND In contrast to cisgender persons, transgender persons identify with a different gender than the one assigned at birth. Although research on the underlying neurobiology of transgender persons has been accumulating over the years, neuroimaging studies in this relatively rare population are often based on very small samples resulting in discrepant findings. AIM To examine the neurobiology of transgender persons in a large sample. METHODS Using a mega-analytic approach, structural MRI data of 803 non-hormonally treated transgender men (TM, n = 214, female assigned at birth with male gender identity), transgender women (TW, n = 172, male assigned at birth with female gender identity), cisgender men (CM, n = 221, male assigned at birth with male gender identity) and cisgender women (CW, n = 196, female assigned at birth with female gender identity) were analyzed. OUTCOMES Structural brain measures, including grey matter volume, cortical surface area, and cortical thickness. RESULTS Transgender persons differed significantly from cisgender persons with respect to (sub)cortical brain volumes and surface area, but not cortical thickness. Contrasting the 4 groups (TM, TW, CM, and CW), we observed a variety of patterns that not only depended on the direction of gender identity (towards male or towards female) but also on the brain measure as well as the brain region examined. CLINICAL TRANSLATION The outcomes of this large-scale study may provide a normative framework that may become useful in clinical studies. STRENGTHS AND LIMITATIONS While this is the largest study of MRI data in transgender persons to date, the analyses conducted were governed (and restricted) by the type of data collected across all participating sites. CONCLUSION Rather than being merely shifted towards either end of the male-female spectrum, transgender persons seem to present with their own unique brain phenotype. Mueller SC, Guillamon A, Zubiaurre-Elorza L, et al. The Neuroanatomy of Transgender Identity: Mega-Analytic Findings From the ENIGMA Transgender Persons Working Group. J Sex Med 2021;18:1122-1129.
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Affiliation(s)
- Sven C Mueller
- Department of Experimental Clinical and Health Psychology, Ghent University, Ghent, Belgium
- Department of Personality, Psychological Assessment and Treatment, University of Deusto, Bilbao, Spain
| | - Antonio Guillamon
- Deparment of Psychobiology, National Distance Education University, Madrid, Spain
| | - Leire Zubiaurre-Elorza
- Department of Methods and Experimental Psychology, Faculty of Psychology and Education, University of Deusto, Bilbao, Spain
| | - Carme Junque
- Faculty of Medicine, University of Barcelona, Barcelona, Spain
| | | | - Carme Uribe
- Faculty of Medicine, University of Barcelona, Barcelona, Spain
| | - Behzad S Khorashad
- Psychiatry and Behavioral Sciences Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
- Department of Women's and Children's Health, Karolinska University Hospital, Karolinska Institute, Solna, Stockholm, Sweden
| | - Behnaz Khazai
- Keck School of Medicine, Mark and Mary Stevens Neuroimaging and Informatics Institute, Los Angeles, CA, USA
| | - Ali Talaei
- Psychiatry and Behavioral Sciences Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Ute Habel
- Psychiatry, Psychotherapy, and Psychosomatics, University Clinic RWTH, Aachen, Germany
- Research Centre Jülich, Institute of Neuroscience and Medicine (INM-10), Jülich, Germany
| | - Mikhail Votinov
- Psychiatry, Psychotherapy, and Psychosomatics, University Clinic RWTH, Aachen, Germany
- Research Centre Jülich, Institute of Neuroscience and Medicine (INM-10), Jülich, Germany
| | - Birgit Derntl
- Deptarment of Psychiatry and Psychotherapy, University of Tuebingen, Germany
| | - Rupert Lanzenberger
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Vienna, Austria
| | - Rene Seiger
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Vienna, Austria
| | - Georg S Kranz
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Vienna, Austria
- Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Hongkong
| | | | | | - Sarah M Burke
- Psychology, Developmental and Educational Psychology, University of Leiden, Leiden, The Netherlands
| | - Nils B Lambalk
- Obstetrics and Gynaecology, Amsterdam University Medical Center, Amsterdam, The Netherlands
| | - Dick J Veltman
- Psychiatry, Amsterdam University Medical Center, Amsterdam, The Netherlands
| | - Mathilde Kennis
- Department of Cognitive Neuroscience, Maastricht University, Maastricht, The Netherlands
| | | | - Eric Vilain
- Center for Genetic Medicine Research, Children's National Hospital, Washington, DC, USA
- Department of Genomics and Precision Medicine, George Washington University, Washington, DC, USA
| | - Alessandra Daphne Fisher
- Andrology, Women's Endocrinology, Gender Incongruence Unit, Careggi University Hospital, Florence, Italy
| | - Mario Mascalchi
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, Florence, Italy
| | - Gioele Gavazzi
- Department of Neuroscience, Psychology, Drug Research, Child Health, University of Florence, Florence, Italy
| | - Stefano Orsolini
- Department of Electrical, Electronic, and Information Engineering "Guglielmo Marconi", University of Bologna, Cesena, Italy
| | - Jiska Ristori
- Center for Genetic Medicine Research, Children's National Hospital, Washington, DC, USA
| | - Udo Dannlowski
- Institute for Translational Psychiatry, University of Muenster, Muenster, Germany
| | - Dominik Grotegerd
- Institute for Translational Psychiatry, University of Muenster, Muenster, Germany
| | - Carsten Konrad
- Department of Psychiatry and Psychotherapy, Agaplesion Diakonieklinikum, Rotenburg, Germany
| | | | - Guy T'Sjoen
- Department of Endocrinology & Center for Sexology and Gender, Ghent University Hospital, Ghent, Belgium
| | - Eileen Luders
- School of Psychology, University of Auckland, Auckland, New Zealand
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Abstract
This paper explores the therapeutic process between analyst and Josh, a trans man whose life had fallen apart after transition. Repetitive enactments involving hiding, deceiving and mystification constituted a prolonged therapeutic impasse. The analyst's struggle with these binds and with countertransference confusion and anxiety, ultimately illuminated zones that had remained off-limits for a prolonged period of time. Where the couple had been snared in a bind structured by gender, they were now able to access a history of violation and to ask more profound questions about connection, aloneness, authenticity and loss.
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Clemens B, Votinov M, Puiu AA, Schüppen A, Hüpen P, Neulen J, Derntl B, Habel U. Replication of Previous Findings? Comparing Gray Matter Volumes in Transgender Individuals with Gender Incongruence and Cisgender Individuals. J Clin Med 2021; 10:1454. [PMID: 33916288 PMCID: PMC8037365 DOI: 10.3390/jcm10071454] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Revised: 03/23/2021] [Accepted: 03/29/2021] [Indexed: 01/30/2023] Open
Abstract
The brain structural changes related to gender incongruence (GI) are still poorly understood. Previous studies comparing gray matter volumes (GMV) between cisgender and transgender individuals with GI revealed conflicting results. Leveraging a comprehensive sample of transmen (n = 33), transwomen (n = 33), cismen (n = 24), and ciswomen (n = 25), we employ a region-of-interest (ROI) approach to examine the most frequently reported brain regions showing GMV differences between trans- and cisgender individuals. The primary aim is to replicate previous findings and identify anatomical regions which differ between transgender individuals with GI and cisgender individuals. On the basis of a comprehensive literature search, we selected a set of ROIs (thalamus, putamen, cerebellum, angular gyrus, precentral gyrus) for which differences between cis- and transgender groups have been previously observed. The putamen was the only region showing significant GMV differences between cis- and transgender, across previous studies and the present study. We observed increased GMV in the putamen for transwomen compared to both transmen and ciswomen and for all transgender participants compared to all cisgender participants. Such a pattern of neuroanatomical differences corroborates the large majority of previous studies. This potential replication of previous findings and the known involvement of the putamen in cognitive processes related to body representations and the creation of the own body image indicate the relevance of this region for GI and its potential as a structural biomarker for GI.
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Affiliation(s)
- Benjamin Clemens
- Department of Psychiatry, Psychotherapy and Psychosomatics, Faculty of Medicine, RWTH Aachen University, 52062 Aachen, Germany; (M.V.); (A.A.P.); (P.H.); (U.H.)
- Institute of Neuroscience and Medicine 10, Research Centre Jülich, 52428 Jülich, Germany
| | - Mikhail Votinov
- Department of Psychiatry, Psychotherapy and Psychosomatics, Faculty of Medicine, RWTH Aachen University, 52062 Aachen, Germany; (M.V.); (A.A.P.); (P.H.); (U.H.)
- Institute of Neuroscience and Medicine 10, Research Centre Jülich, 52428 Jülich, Germany
| | - Andrei Alexandru Puiu
- Department of Psychiatry, Psychotherapy and Psychosomatics, Faculty of Medicine, RWTH Aachen University, 52062 Aachen, Germany; (M.V.); (A.A.P.); (P.H.); (U.H.)
- Institute of Neuroscience and Medicine 10, Research Centre Jülich, 52428 Jülich, Germany
| | - Andre Schüppen
- Interdisciplinary Center for Clinical Research (IZKF), Faculty of Medicine, RWTH Aachen University, 52062 Aachen, Germany;
- Division for Clinical and Cognitive Sciences, Department of Neurology, Faculty of Medicine, RWTH Aachen University, 52062 Aachen, Germany
| | - Philippa Hüpen
- Department of Psychiatry, Psychotherapy and Psychosomatics, Faculty of Medicine, RWTH Aachen University, 52062 Aachen, Germany; (M.V.); (A.A.P.); (P.H.); (U.H.)
- Institute of Neuroscience and Medicine 10, Research Centre Jülich, 52428 Jülich, Germany
| | - Josef Neulen
- Department of Gynecological Endocrinology and Reproductive Medicine, Faculty of Medicine, RWTH Aachen University, 52062 Aachen, Germany;
| | - Birgit Derntl
- Department of Psychiatry and Psychotherapy, University of Tübingen, 72074 Tübingen, Germany;
- LEAD Graduate School and Research Network, University of Tübingen, 72072 Tübingen, Germany
| | - Ute Habel
- Department of Psychiatry, Psychotherapy and Psychosomatics, Faculty of Medicine, RWTH Aachen University, 52062 Aachen, Germany; (M.V.); (A.A.P.); (P.H.); (U.H.)
- Institute of Neuroscience and Medicine 10, Research Centre Jülich, 52428 Jülich, Germany
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A Multi-Modal MRI Analysis of Cortical Structure in Relation to Gender Dysphoria, Sexual Orientation, and Age in Adolescents. J Clin Med 2021; 10:jcm10020345. [PMID: 33477567 PMCID: PMC7831120 DOI: 10.3390/jcm10020345] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 12/20/2020] [Accepted: 12/23/2020] [Indexed: 01/18/2023] Open
Abstract
Gender dysphoria (GD) is characterized by distress due to an incongruence between experienced gender and sex assigned at birth. Sex-differentiated brain regions are hypothesized to reflect the experienced gender in GD and may play a role in sexual orientation development. Magnetic resonance brain images were acquired from 16 GD adolescents assigned female at birth (AFAB) not receiving hormone therapy, 17 cisgender girls, and 14 cisgender boys (ages 12–17 years) to examine three morphological and microstructural gray matter features in 76 brain regions: surface area (SA), cortical thickness (CT), and T1 relaxation time. Sexual orientation was represented by degree of androphilia-gynephilia and sexual attraction strength. Multivariate analyses found that cisgender boys had larger SA than cisgender girls and GD AFAB. Shorter T1, reflecting denser, macromolecule-rich tissue, correlated with older age and stronger gynephilia in cisgender boys and GD AFAB, and with stronger attractions in cisgender boys. Thus, cortical morphometry (mainly SA) was related to sex assigned at birth, but not experienced gender. Effects of experienced gender were found as similarities in correlation patterns in GD AFAB and cisgender boys in age and sexual orientation (mainly T1), indicating the need to consider developmental trajectories and sexual orientation in brain studies of GD.
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Siegmann EM, Müller T, Dziadeck I, Mühle C, Lenz B, Kornhuber J. Digit ratio (2D:4D) and transgender identity: new original data and a meta-analysis. Sci Rep 2020; 10:19326. [PMID: 33168880 PMCID: PMC7653965 DOI: 10.1038/s41598-020-72486-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Accepted: 09/02/2020] [Indexed: 01/20/2023] Open
Abstract
Previously reported associations between second-to-fourth digit length ratio (2D:4D), a proxy for prenatal androgen load, and transgender identity have been inconsistent. The objectives of the present study were to provide additional original data and an updated meta-analysis concerning this association. In a study of 464 participants, we compared the 2D:4D of transgender individuals with age- and sex-matched controls. Patients were recruited at a specialized psychiatrist's medical office, whereas controls were hired via flyers, advertisements, and as convenience sample. A random-effects meta-analysis of the literature (17 samples, n = 3674) also quantifies the overall magnitude of the difference in 2D:4D between transgender individuals and controls. In our study providing new original data, we found a significantly higher (i.e. feminized) left-hand 2D:4D in the male-to-female transgender (MtF) identity [mean age: 32.3 (18; 61)] than in the male control group [mean age: 34.5 (18; 65)] with a Cohen's d = 0.271. Concordantly, the meta-analytic results suggest a significant difference in 2D:4D among MtF individuals compared to male controls [g = 0.153; 95% CI (0.063; 0.243)], which was even more pronounced when individuals had been diagnosed by a clinician instead of self-identified as transgender [g = 0.193; 95% CI (0.086; 0.300)]. In both studies, no significant results were revealed for female-to-male transgender individuals [mean age: 26.1 (18; 53)] versus female controls [mean age: 27.2 (18; 55)]. This original investigation and the updated meta-analysis clarify the association between transgender identity and 2D:4D indicating the influence of prenatal androgen on the development of gender identity in subjects born as males.
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Affiliation(s)
- Eva-Maria Siegmann
- Department of Psychiatry and Psychotherapy, Friedrich-Alexander University Erlangen-Nürnberg (FAU), Schwabachanlage 6, 91054, Erlangen, Germany.
| | - Tobias Müller
- Department of Psychiatry and Psychotherapy, Friedrich-Alexander University Erlangen-Nürnberg (FAU), Schwabachanlage 6, 91054, Erlangen, Germany
- Psychiatric Practice, Treibberg 5, 90403, Nuremberg, Germany
| | - Isabelle Dziadeck
- Department of Psychiatry and Psychotherapy, Friedrich-Alexander University Erlangen-Nürnberg (FAU), Schwabachanlage 6, 91054, Erlangen, Germany
| | - Christiane Mühle
- Department of Psychiatry and Psychotherapy, Friedrich-Alexander University Erlangen-Nürnberg (FAU), Schwabachanlage 6, 91054, Erlangen, Germany
| | - Bernd Lenz
- Department of Psychiatry and Psychotherapy, Friedrich-Alexander University Erlangen-Nürnberg (FAU), Schwabachanlage 6, 91054, Erlangen, Germany
- Department of Addictive Behavior and Addiction Medicine, Central Institute of Mental Health (CIMH), Medical Faculty Mannheim, Heidelberg University, Heidelberg, Germany
| | - Johannes Kornhuber
- Department of Psychiatry and Psychotherapy, Friedrich-Alexander University Erlangen-Nürnberg (FAU), Schwabachanlage 6, 91054, Erlangen, Germany
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Palmer BF, Clegg DJ. A Universally Accepted Definition of Gender Will Positively Impact Societal Understanding, Acceptance, and Appropriateness of Health Care. Mayo Clin Proc 2020; 95:2235-2243. [PMID: 32448588 DOI: 10.1016/j.mayocp.2020.01.031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Revised: 01/13/2020] [Accepted: 01/24/2020] [Indexed: 11/21/2022]
Abstract
When individuals do not conform to stereotypes associated with "male" or "female," they are often ridiculed, bullied, and rejected, which leads to depression, psychological problems, and even suicide. The number of individuals who identify themselves as transgender, gender queer, or who do not conform to societal norms with respect to gender appears to be increasing. Despite this apparent increase, clinicians and health care facilities are ill-prepared to meet the needs of these individuals in a professional and appropriate manner. Unfortunately, there is an inherit distrust of the medical community by individuals who do not conform to societal norms with respect to gender because of a perception that the medical community does not understand the unique challenges of these individuals. Therefore, reducing the social stigma associated with gender nonconforming individuals is one way to begin to break down barriers of distrust and enhance communication within and outside the medical community. In this review, we discuss the scant amount of scientific data on the biological origins of gender identity. We highlight the fact that the biological definition of gender remains elusive in part because molecular and biological techniques have not been available to accurately probe the development of gender identity. We therefore advocate for the importance of enhancing our knowledge of the origins of gender identity with advanced scientific tools. Enhancing scientific understanding of the biological origins of gender identity may reduce stigma and barriers to care.
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Affiliation(s)
- Biff F Palmer
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas
| | - Deborah J Clegg
- College of Nursing and Health Professions, Drexel University, Philadelphia, PA.
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Sorouri Khorashad B, Khazai B, Talaei A, Acar F, Hudson AR, Borji N, Saberi H, Aminzadeh B, Mueller SC. Neuroanatomy of transgender persons in a Non-Western population and improving reliability in clinical neuroimaging. J Neurosci Res 2020; 98:2166-2177. [PMID: 32776583 DOI: 10.1002/jnr.24702] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 07/02/2020] [Accepted: 07/09/2020] [Indexed: 01/22/2023]
Abstract
Although the neuroanatomy of transgender persons is slowly being charted, findings are presently discrepant. Moreover, the major body of work has focused on Western populations. One important factor is the issue of power and low signal-to-noise (SNR) ratio in neuroimaging studies of rare study populations including endocrine or neurological patient groups. The present study focused on the structural neuroanatomy of a Non-Western (Iranian) sample of 40 transgender men (TM), 40 transgender women (TW), 30 cisgender men (CM), and 30 cisgender women (CW), while assessing whether the reliability of findings across structural anatomical measures including gray matter volume (GMV), cortical surface area (CSA), and cortical thickness (CTh) could be increased by using two back-to-back within-session structural MRI scans. Overall, findings in transgender persons were more consistent with sex assigned at birth in GMV and CSA, while no group differences emerged for CTh. Repeated measures analysis also indicated that having a second scan increased SNR in all regions of interest, most notably bilateral frontal poles, pre- and postcentral gyri and putamina. The results suggest that a simple time and cost-effective measure to improve SNR in rare clinical populations with low prevalence rates is a second anatomical scan when structural MRI is of interest.
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Affiliation(s)
- Behzad Sorouri Khorashad
- Department of Women's and Children's Health, Karolinska Institutet, Stockholm, Solna, Sweden.,Psychiatry and Behavioral Sciences Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Behnaz Khazai
- Mark and Mary Stevens Neuroimaging and Informatics Institute, Keck School of Medicine of University of Southern California, Los Angeles, CA, USA
| | - Ali Talaei
- Psychiatry and Behavioral Sciences Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Freya Acar
- Department of Data Analysis, Ghent University, Ghent, Belgium
| | - Anna R Hudson
- Department of Experimental Clinical and Health Psychology, Ghent University, Ghent, Belgium
| | - Nahid Borji
- Department of Radiology, Faculty of Medicine, Ghaem Hospital, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Hedieh Saberi
- Department of Biology, Faculty of Science, Ferdowsi University of Mashhad, Mashhad, Iran
| | - Behzad Aminzadeh
- Department of Radiology, Faculty of Medicine, Ghaem Hospital, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Sven C Mueller
- Department of Experimental Clinical and Health Psychology, Ghent University, Ghent, Belgium.,Department of Personality, Psychological Assessment and Treatment, University of Deusto, Bilbao, Spain
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Byne W, Karasic DH, Coleman E, Eyler AE, Kidd JD, Meyer-Bahlburg HFL, Pleak RR, Pula J. Gender Dysphoria in Adults: An Overview and Primer for Psychiatrists. FOCUS: JOURNAL OF LIFE LONG LEARNING IN PSYCHIATRY 2020; 18:336-350. [PMID: 33343244 DOI: 10.1176/appi.focus.18304] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
(Copyright © William Byne et al. 2018; Published by Mary Ann Liebert, Inc. This Open Access article is distributed under the terms of the Creative Commons License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.).
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Analysis of Four Polymorphisms Located at the Promoter of the Estrogen Receptor Alpha ESR1 Gene in a Population With Gender Incongruence. Sex Med 2020; 8:490-500. [PMID: 32409288 PMCID: PMC7471065 DOI: 10.1016/j.esxm.2020.04.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Revised: 03/28/2020] [Accepted: 04/05/2020] [Indexed: 02/06/2023] Open
Abstract
INTRODUCTION Gender incongruence defines a state in which individuals feel discrepancy between the sex assigned at birth and their gender. Some of these people make a social transition from male to female (trans women) or from female to male (trans men). By contrast, the word cisgender describes a person whose gender identity is consistent with their sex assigned at birth. AIM To analyze the implication of the estrogen receptor α gene (ESR1) in the genetic basis of gender incongruence. MAIN OUTCOME MEASURES Polymorphisms rs9478245, rs3138774, rs2234693, rs9340799. METHOD We carried out the analysis of 4 polymorphisms located at the promoter of the ESR1 gene (C1 = rs9478245, C2 = rs3138774, C3 = rs2234693, and C4 = rs9340799) in a population of 273 trans women, 226 trans men, and 537 cis gender controls. For SNP polymorphisms, the allele and genotype frequencies were analyzed by χ2 test. The strength of the SNP associations with gender incongruence was measured by binary logistic regression. For the STR polymorphism, the mean number of repeats were analyzed by the Mann-Whitney U test. Measurement of linkage disequilibrium and haplotype frequencies were also performed. RESULTS The C2 median repeats were shorter in the trans men population. Genotypes S/S and S/L for the C2 polymorphism were overrepresented in the trans men group (P = .012 and P = .003 respectively). We also found overtransmission of the A/A genotype (C4) in the trans men population (P = .017), while the A/G genotype (C4) was subrepresented (P = .009]. The analyzed polymorphisms were in linkage disequilibrium. In the trans men population, the T(C1)-L(C2)-C(C3)-A(C4) haplotype was overrepresented (P = .019) while the T(C1)-L(C2)-C(C3)-G(C4) was subrepresented (P = .005). CONCLUSION The ESR1 is associated with gender incongruence in the trans men population. Fernández R, Delgado-Zayas E,RamírezK, et al. Analysis of Four Polymorphisms Located at the Promoter of the Estrogen Receptor Alpha ESR1 Gene in a Population With Gender Incongruence. Sex Med 2020;8:490-500.
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Uribe C, Junque C, Gómez-Gil E, Abos A, Mueller SC, Guillamon A. Brain network interactions in transgender individuals with gender incongruence. Neuroimage 2020; 211:116613. [DOI: 10.1016/j.neuroimage.2020.116613] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Accepted: 02/04/2020] [Indexed: 12/31/2022] Open
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Strath LJ, Sorge RE, Owens MA, Gonzalez CE, Okunbor JI, White DM, Merlin JS, Goodin BR. Sex and Gender are Not the Same: Why Identity Is Important for People Living with HIV and Chronic Pain. J Pain Res 2020; 13:829-835. [PMID: 32425587 PMCID: PMC7187934 DOI: 10.2147/jpr.s248424] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Accepted: 04/02/2020] [Indexed: 01/22/2023] Open
Abstract
Background Sex differences in pain sensitivity have been well documented, such that women often report greater sensitivity than men. However, clinical reports highlighting sex differences often equate gender and sex. This is a particularly critical oversight for those whose gender identity is different than their genetic sex. Methods This preliminary study sets to analyze differences in pain responses between cisgender and transgender individuals living with HIV and chronic pain. A total of 51 African-American participants (24 cisgender men, 20 cisgender women, 7 transgender women) with similar socioeconomic status were recruited. Genetic sex, gender identity, depression and anxiety, pain severity, pain interference and pain-related stigma were recorded. Participants also completed a quantitative sensory testing battery to assess pain in response to noxious heat and mechanical stimuli. Results Transgender women and cisgender women demonstrated a greater magnitude of temporal summation for heat pain stimuli or mechanical stimuli compared to cisgender men. Specifically, transgender women reported greater mechanical summation than either cisgender women or cisgender men. Transgender women and cisgender women similarly reported greater chronic pain severity compared to cisgender men. Conclusion These data support the notion that gender identity may play a more significant role in pain sensation than genetic sex. These results further maintain that not only gender identity and genetic sex are distinct variables but that treatment should be based on identity as opposed to genetic sex.
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Affiliation(s)
- Larissa J Strath
- University of Alabama at Birmingham, Department of Psychology, Birmingham, AL, USA
| | - Robert E Sorge
- University of Alabama at Birmingham, Department of Psychology, Birmingham, AL, USA
| | - Michael A Owens
- University of Alabama at Birmingham, Department of Psychology, Birmingham, AL, USA
| | - Cesar E Gonzalez
- University of Alabama at Birmingham, Department of Psychology, Birmingham, AL, USA
| | - Jennifer I Okunbor
- University of Alabama at Birmingham, Department of Psychology, Birmingham, AL, USA
| | - Dyan M White
- University of Alabama at Birmingham, Department of Psychology, Birmingham, AL, USA
| | - Jessica S Merlin
- University of Pittsburgh, Department of Medicine, Divisions of General Internal Medicine and Infectious Diseases, Pittsburgh, PA, USA
| | - Burel R Goodin
- University of Alabama at Birmingham, Department of Psychology, Birmingham, AL, USA
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42
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Kranz GS, Zhang BBB, Handschuh P, Ritter V, Lanzenberger R. Gender-affirming hormone treatment - A unique approach to study the effects of sex hormones on brain structure and function. Cortex 2020; 129:68-79. [PMID: 32438011 DOI: 10.1016/j.cortex.2020.04.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Revised: 03/23/2020] [Accepted: 04/09/2020] [Indexed: 12/22/2022]
Abstract
Investigating the effects of the gender-affirming hormone treatment of transgender people using neuroimaging provides a unique opportunity to study the impact of high dosages of sex hormones on human brain structure and function. This line of research is of relevance from a basic neuroscientific as well as from a psychiatric viewpoint. Prevalence rates, etiopathology, and disease course of many psychiatric disorders exhibit sex differences which are linked to differences in sex hormone levels. Here, we review recent neuroimaging studies from others and our group that investigate the effects of gender-affirming hormone treatment in a longitudinal design utilizing structural and functional magnetic resonance imaging and positron emission tomography. Studies point to a general anabolic and anticatabolic effect of testosterone on grey and white matter structure, whereas estradiol and antiandrogen treatment seems to have partly opposite effects. Moreover, preliminary research indicates that gender-affirming hormone treatment influences serotonergic neurotransmission, a finding that is especially interesting for psychiatry. A clear picture of a hormonal influence on brain activity has yet to emerge. In conclusion, the available evidence reviewed here clearly indicates that sex hormone applications influence brain structure and function in the adult human brain.
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Affiliation(s)
- Georg S Kranz
- Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Hong Kong, SAR, China; Department of Psychiatry and Psychotherapy, Medical University of Vienna, Vienna, Austria; The State Key Laboratory of Brain and Cognitive Sciences, The University of Hong Kong, Hong Kong, SAR, China.
| | - Bella B B Zhang
- Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Hong Kong, SAR, China
| | - Patricia Handschuh
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Vienna, Austria
| | - Vera Ritter
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Vienna, Austria
| | - Rupert Lanzenberger
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Vienna, Austria
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43
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Sadr M, Khorashad BS, Talaei A, Fazeli N, Hönekopp J. 2D:4D Suggests a Role of Prenatal Testosterone in Gender Dysphoria. ARCHIVES OF SEXUAL BEHAVIOR 2020; 49:421-432. [PMID: 31975034 PMCID: PMC7031197 DOI: 10.1007/s10508-020-01630-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Revised: 01/03/2020] [Accepted: 01/06/2020] [Indexed: 06/10/2023]
Abstract
Gender dysphoria (GD) reflects distress caused by incongruence between one's experienced gender identity and one's natal (assigned) gender. Previous studies suggest that high levels of prenatal testosterone (T) in natal females and low levels in natal males might contribute to GD. Here, we investigated if the 2D:4D digit ratio, a biomarker of prenatal T effects, is related to GD. We first report results from a large Iranian sample, comparing 2D:4D in 104 transwomen and 89 transmen against controls of the same natal sex. We found significantly lower (less masculine) 2D:4D in transwomen compared to control men. We then conducted random-effects meta-analyses of relevant studies including our own (k = 6, N = 925 for transwomen and k = 6, N = 757 for transmen). In line with the hypothesized prenatal T effects, transwomen showed significantly feminized 2D:4D (d ≈ 0.24). Conversely, transmen showed masculinized 2D:4D (d ≈ - 0.28); however, large unaccounted heterogeneity across studies emerged, which makes this effect less meaningful. These findings support the idea that high levels of prenatal T in natal females and low levels in natal males play a part in the etiology of GD. As we discuss, this adds to the evidence demonstrating the convergent validity of 2D:4D as a marker of prenatal T effects.
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Affiliation(s)
- Mostafa Sadr
- Transgender Studies Centre, Psychiatry and Behavioral Sciences Research Centre, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Behzad S Khorashad
- Transgender Studies Centre, Psychiatry and Behavioral Sciences Research Centre, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Ali Talaei
- Transgender Studies Centre, Psychiatry and Behavioral Sciences Research Centre, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Nasrin Fazeli
- Transgender Studies Centre, Psychiatry and Behavioral Sciences Research Centre, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Johannes Hönekopp
- Department of Psychology, Northumbria University, Newcastle upon Tyne, NE1 8ST, UK.
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44
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Burke SM, van Heesewijk JO, Menks WM, Klink DT, Kreukels BPC, Cohen-Kettenis PT, Bakker J. Postnatal Effects of Sex Hormones on Click-Evoked Otoacoustic Emissions: A Study of Adolescents with Gender Dysphoria. ARCHIVES OF SEXUAL BEHAVIOR 2020; 49:455-465. [PMID: 32056039 PMCID: PMC7031217 DOI: 10.1007/s10508-020-01652-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Revised: 01/25/2020] [Accepted: 01/27/2020] [Indexed: 06/10/2023]
Abstract
Click-evoked otoacoustic emissions (CEOAEs) are echo-like sounds, generated by the inner ear in response to click-stimuli. A sex difference in emission strength is observed in neonates and adults, with weaker CEOAE amplitudes in males. These differences are assumed to originate from testosterone influences during prenatal male sexual differentiation and to remain stable throughout life. However, recent studies suggested activational, postnatal effects of sex hormones on CEOAEs. Adolescents diagnosed with gender dysphoria (GD) may receive gonadotropin-releasing hormone analogs (GnRHa) in order to suppress endogenous sex hormones and, therefore, pubertal maturation, followed by cross-sex hormone (CSH) treatment. Using a cross-sectional design, we examined whether hormonal interventions in adolescents diagnosed with GD (62 trans boys, assigned female at birth, self-identifying as male; 43 trans girls, assigned male at birth, self-identifying as female), affected their CEOAEs compared to age- and sex-matched controls (44 boys, 37 girls). Sex-typical differences in CEOAE amplitude were observed among cisgender controls and treatment-naïve trans boys but not in other groups with GD. Treatment-naïve trans girls tended to have more female-typical CEOAEs, suggesting hypomasculinized early sexual differentiation, in support of a prominent hypothesis on the etiology of GD. In line with the predicted suppressive effects of androgens, trans boys receiving CSH treatment, i.e., testosterone plus GnRHa, showed significantly weaker right-ear CEOAEs compared with control girls. A similar trend was seen in trans boys treated with GnRHa only. Unexpectedly, trans girls showed CEOAE masculinization with addition of estradiol. Our findings show that CEOAEs may not be used as an unequivocal measure of prenatal androgen exposure as they can be modulated postnatally by sex hormones, in the form of hormonal treatment.
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Affiliation(s)
- Sarah M Burke
- Department of Medical Psychology, Center of Expertise on Gender Dysphoria, Amsterdam University Medical Centers, 1081 HX, Amsterdam, The Netherlands
- Department of Developmental and Educational Psychology, Brain and Development Research Center, Leiden University, Leiden, The Netherlands
| | - Jason O van Heesewijk
- Department of Medical Psychology, Center of Expertise on Gender Dysphoria, Amsterdam University Medical Centers, 1081 HX, Amsterdam, The Netherlands.
| | - Willeke M Menks
- Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, The Netherlands
| | - Daniel T Klink
- Department of Pediatric Endocrinology, Center of Expertise on Gender Dysphoria, Amsterdam University Medical Centers, Location VUmc, Amsterdam, The Netherlands
- Pediatrics and Genetics Research Unit, Division of Pediatric Endocrinology, Department of Pediatrics, Ghent University Hospital, Ghent University, Ghent, Belgium
| | - Baudewijntje P C Kreukels
- Department of Medical Psychology, Center of Expertise on Gender Dysphoria, Amsterdam University Medical Centers, 1081 HX, Amsterdam, The Netherlands
| | - Peggy T Cohen-Kettenis
- Department of Medical Psychology, Center of Expertise on Gender Dysphoria, Amsterdam University Medical Centers, 1081 HX, Amsterdam, The Netherlands
| | - Julie Bakker
- GIGA Neuroscience, University of Liege, Liège, Belgium
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45
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Clemens B, Derntl B, Smith E, Junger J, Neulen J, Mingoia G, Schneider F, Abel T, Bzdok D, Habel U. Predictive Pattern Classification Can Distinguish Gender Identity Subtypes from Behavior and Brain Imaging. Cereb Cortex 2020; 30:2755-2765. [PMID: 31999324 DOI: 10.1093/cercor/bhz272] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Revised: 08/02/2019] [Accepted: 09/12/2019] [Indexed: 11/13/2022] Open
Abstract
The exact neurobiological underpinnings of gender identity (i.e., the subjective perception of oneself belonging to a certain gender) still remain unknown. Combining both resting-state functional connectivity and behavioral data, we examined gender identity in cisgender and transgender persons using a data-driven machine learning strategy. Intrinsic functional connectivity and questionnaire data were obtained from cisgender (men/women) and transgender (trans men/trans women) individuals. Machine learning algorithms reliably detected gender identity with high prediction accuracy in each of the four groups based on connectivity signatures alone. The four normative gender groups were classified with accuracies ranging from 48% to 62% (exceeding chance level at 25%). These connectivity-based classification accuracies exceeded those obtained from a widely established behavioral instrument for gender identity. Using canonical correlation analyses, functional brain measurements and questionnaire data were then integrated to delineate nine canonical vectors (i.e., brain-gender axes), providing a multilevel window into the conventional sex dichotomy. Our dimensional gender perspective captures four distinguishable brain phenotypes for gender identity, advocating a biologically grounded reconceptualization of gender dimorphism. We hope to pave the way towards objective, data-driven diagnostic markers for gender identity and transgender, taking into account neurobiological and behavioral differences in an integrative modeling approach.
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Affiliation(s)
- Benjamin Clemens
- Department of Psychiatry, Psychotherapy and Psychosomatics, Faculty of Medicine, RWTH Aachen, 52074 Aachen, Germany.,Institute of Neuroscience and Medicine: JARA-Institute Brain Structure Function Relationship (INM 10), Wilhelm-Johnen-Straße 52425 Jülich, Germany
| | - Birgit Derntl
- Department of Psychiatry and Psychotherapy, University of Tübingen, 72076 Tübingen, Germany.,Werner Reichardt Center for Integrative Neuroscience (CIN), University of Tübingen, Otfried-Müller-Str. 25, 72076 Tübingen, Germany.,LEAD Research Network, Walter-Simon-Straße 12, 72072 Tübingen, Germany
| | - Elke Smith
- Department of Psychiatry, Psychotherapy and Psychosomatics, Faculty of Medicine, RWTH Aachen, 52074 Aachen, Germany.,Department of Psychology, Biological Psychology, University of Cologne, Bernhard-Feilchenfeld-Str. 11, 50969 Cologne, Germany
| | - Jessica Junger
- Department of Psychiatry, Psychotherapy and Psychosomatics, Faculty of Medicine, RWTH Aachen, 52074 Aachen, Germany.,Institute of Neuroscience and Medicine: JARA-Institute Brain Structure Function Relationship (INM 10), Wilhelm-Johnen-Straße 52425 Jülich, Germany
| | - Josef Neulen
- Department of Gynecological Endocrinology and Reproductive Medicine, Faculty of Medicine, RWTH Aachen University, 52074 Aachen, Germany
| | - Gianluca Mingoia
- Interdisciplinary Center for Clinical Research (IZKF), RWTH Aachen University, Faculty of Medicine, Pauwelsstrasse 30, 52074 Aachen, Germany
| | - Frank Schneider
- Institute of Neuroscience and Medicine: JARA-Institute Brain Structure Function Relationship (INM 10), Wilhelm-Johnen-Straße 52425 Jülich, Germany.,University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, Moorenstrasse 5, 40225 Düsseldorf, Germany
| | - Ted Abel
- Department of Biology, University of Pennsylvania, 433 South University Avenue, Philadelphia, PA 19104, United States.,Department of Neuroscience & Pharmacology, Iowa Neuroscience Institute, Carver College of Medicine, University of Iowa, 51 Newton Road 5-660 Bowen Science Building, Iowa City, IA 52242, United States
| | - Danilo Bzdok
- Department of Psychiatry, Psychotherapy and Psychosomatics, Faculty of Medicine, RWTH Aachen, 52074 Aachen, Germany.,Institute of Neuroscience and Medicine: JARA-Institute Brain Structure Function Relationship (INM 10), Wilhelm-Johnen-Straße 52425 Jülich, Germany.,Parietal Team, INRIA/Neurospin Saclay, 1 rue Honoré d'Estienne d'Orves, Campus de l'École Polytechnique, 91120 Palaiseau, France.,Department of Biomedical Engineering, Faculty of Medicine, McGill University, 3775, rue University Montréal, QC H3A 2B4, Canada.,Montreal Institute for Learning Algorithms (MILA), 6666 St-Urbain, #200 Montreal, QC H2S 3H1, Canada
| | - Ute Habel
- Department of Psychiatry, Psychotherapy and Psychosomatics, Faculty of Medicine, RWTH Aachen, 52074 Aachen, Germany.,Institute of Neuroscience and Medicine: JARA-Institute Brain Structure Function Relationship (INM 10), Wilhelm-Johnen-Straße 52425 Jülich, Germany
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46
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Peper JS, Burke SM, Wierenga LM. Sex differences and brain development during puberty and adolescence. HANDBOOK OF CLINICAL NEUROLOGY 2020; 175:25-54. [PMID: 33008529 DOI: 10.1016/b978-0-444-64123-6.00003-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Sex differences in behavior, and whether these behavioral differences are related to sex differences in brain development, has been a longstanding topic of debate. Presumably, sex differences can provide critically important leads for explaining the etiology of various illnesses that show (i) large sex differences in prevalence and (ii) have an origin before or during adolescence. The general aim of this chapter is to provide an overview of scientific studies on sex differences in normative brain and behavioral development across puberty and adolescence, including the (sex) hormone-driven transition phase of puberty. Moreover, we describe the literature on brain and behavioral development in gender dysphoria, a severe and persistent incongruence between the self-identified gender and the assigned sex at birth. From the literature it becomes clear there is evidence for a specific link between pubertal maturation and developmental changes in arousal, motivation, and emotion. However, this link is rather similar between boys and girls. Moreover, although there is substantial evidence for sex differences in mean brain structure, these have not always been linked to sex differences in behavior, cognition, or psychopathology. Furthermore, there is little evidence for sex differences in brain development and thus, studies so far have been unable to explain sex differences in cognition. Suggestions for future research and methodologic considerations are provided.
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Affiliation(s)
- Jiska S Peper
- Department of Psychology, Leiden University, Leiden, The Netherlands.
| | - Sarah M Burke
- Department of Psychology, Leiden University, Leiden, The Netherlands
| | - Lara M Wierenga
- Department of Psychology, Leiden University, Leiden, The Netherlands
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47
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Rad MS, Shackleford C, Lee KA, Jassin K, Ginges J. Folk theories of gender and anti-transgender attitudes: Gender differences and policy preferences. PLoS One 2019; 14:e0226967. [PMID: 31887173 PMCID: PMC6936834 DOI: 10.1371/journal.pone.0226967] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Accepted: 12/06/2019] [Indexed: 11/19/2022] Open
Abstract
Transgender rights and discrimination against transgender people are growing public policy issues. Theorizing from social, cognitive, and evolutionary psychology suggests that beyond attitudes, discrimination against transgender people may derive from folk theories about what gender is and where it comes from. Transgender identity is met with hostility, in part, because it poses a challenge to the lay view that gender is determined at birth, and based on observable physical and behavioral characteristics. Here, in two pre-registered studies (N = 1323), we asked American adults to indicate the gender of a transgender target who either altered their biology through surgical interventions or altered their outward appearance: to what extent is it their birth-assigned gender or their self-identified gender? Responses correlate strongly with affect toward transgender people, measured by feeling thermometers, yet predict views on transgender people’s right to use their preferred bathrooms above and beyond feelings. Compared to male participants, female participants judge the person’s gender more in line with the self-identified gender than the birth-assigned gender. This is consistent with social and psychological theories that posit high status (e.g., men) and low status (e.g., women) members of social classification systems view group hierarchies in more and less essentialist ways respectively. Gender differences in gender category beliefs decrease with religiosity and conservatism, and are smaller in higher age groups. These results suggest that folk theories of gender, or beliefs about what gender is and how it is determined have a unique role in how transgender people are viewed and treated. Moreover, as evident by the demographic variability of gender category beliefs, folk theories are shaped by social and cultural forces and are amenable to interventions. They offer an alternative pathway to measure policy support and possibly change attitude toward transgender people.
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Affiliation(s)
- Mostafa Salari Rad
- Kahneman-Treisman Center for Behavioral Science & Public Policy, Woodrow Wilson School of Public and International Affairs, Princeton University, Princeton, New Jersey, United States of America
- Department of Psychology, Princeton University, Princeton, New Jersey, United States of America
- Department of Psychology, New School for Social Research, The New School, New York City, New York, United States of America
- * E-mail:
| | - Crystal Shackleford
- Department of Psychology, New School for Social Research, The New School, New York City, New York, United States of America
| | - Kelli Ann Lee
- Department of Psychology, New School for Social Research, The New School, New York City, New York, United States of America
| | - Kate Jassin
- Department of Psychology, New School for Social Research, The New School, New York City, New York, United States of America
| | - Jeremy Ginges
- Department of Psychology, New School for Social Research, The New School, New York City, New York, United States of America
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48
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A New Theory of Gender Dysphoria Incorporating the Distress, Social Behavioral, and Body-Ownership Networks. eNeuro 2019; 6:ENEURO.0183-19.2019. [PMID: 31792116 PMCID: PMC6911960 DOI: 10.1523/eneuro.0183-19.2019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Revised: 10/29/2019] [Accepted: 11/04/2019] [Indexed: 12/16/2022] Open
Abstract
When postmortem studies related to transgender individuals were first published, little was known about the function of the various identified nuclei. Now, over 2 decades later, significant progress has been made associating function with specific brain regions, as well as in identifying networks associated with groups of behaviors. However, much of this progress has not been integrated into the general conceptualization of gender dysphoria in humans. When postmortem studies related to transgender individuals were first published, little was known about the function of the various identified nuclei. Now, over 2 decades later, significant progress has been made associating function with specific brain regions, as well as in identifying networks associated with groups of behaviors. However, much of this progress has not been integrated into the general conceptualization of gender dysphoria in humans. I hypothesize that in individuals with gender dysphoria, the aspects of chronic distress, gender atypical behavior, and incongruence between perception of gender identity and external primary sex characteristics are all directly related to functional differences in associated brain networks. I evaluated previously published neuroscience data related to these aspects and the associated functional networks, along with other relevant information. I find that the brain networks that give individuals their ownership of body parts, that influence gender typical behavior, and that are involved in chronic distress are different in individuals with and without gender dysphoria, leading to a new theory—that gender dysphoria is a sensory perception condition, an alteration in the sense of gender influenced by the reflexive behavioral responses associated with each of these networks. This theory builds upon previous work that supports the relevance of the body-ownership network and that questions the relevance of cerebral sexual dimorphism in regard to gender dysphoria. However, my theory uses a hierarchical executive function model to incorporate multiple reflexive factors (body ownership, gender typical/atypical behavior, and chronic distress) with the cognitive, reflective process of gender identity.
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49
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Meyer-Bahlburg HFL. "Diagnosing" Gender? Categorizing Gender-Identity Variants in the Anthropocene. ARCHIVES OF SEXUAL BEHAVIOR 2019; 48:2027-2035. [PMID: 30607711 DOI: 10.1007/s10508-018-1349-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Revised: 11/07/2018] [Accepted: 11/08/2018] [Indexed: 05/26/2023]
Abstract
In recent decades, two interrelated major controversies have been unfolding in the area of sex/gender research. (1) Are gender-identity variants to be understood as psychopathology or natural variation? (2) Is gender (and perhaps even sex) better conceptualized as binary or non-binary? The answer depends on the conceptual context and related considerations of utility. In the context of evolutionary biology, marked variants of sex and gender decrease reproductive success and are, thereby, deemed pathologic. In the present era of the anthropocene, however, the material conditions underlying the traditional division of labor between the sexes and the role of reproductive success have dramatically changed. These changes decrease the psychosocial importance of the binary gender distinction, provide more freedom for non-binary gender expression and identity formation, and render the distinction of pathologic and non-pathologic less useful, unless gender dysphoria develops secondary to a psychiatric condition. Although most people state their gender identity in the form of a nominal category, most self-report or interview-based ratings and multi-item scales of gender expression and/or identity show continuous distributions, either unimodal-asymmetric or bimodal, depending on whether they are designed for one or both of the traditional genders. Similarly, the rating scales of androgen-influenced variants of the genitalia-usually designed for one of the traditional sexes-typically represent a unipolar-asymmetric continuum. However, the binary gender system remains the primary framework against which individuals evaluate themselves. For those who develop gender dysphoria, assistance by mental-health service providers continues to be important.
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Affiliation(s)
- Heino F L Meyer-Bahlburg
- Department of Psychiatry, NYS Psychiatric Institute, Vagelos College of Physicians and Surgeons of Columbia University, 1051 Riverside Drive, Unit 15, New York, NY, 10032, USA.
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50
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Zucker KJ. Epidemiology of gender dysphoria and transgender identity. Sex Health 2019; 14:404-411. [PMID: 28838353 DOI: 10.1071/sh17067] [Citation(s) in RCA: 222] [Impact Index Per Article: 44.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Accepted: 05/22/2017] [Indexed: 01/11/2023]
Abstract
This review provides an update on the epidemiology of gender dysphoria and transgender identity in children, adolescents and adults. Although the prevalence of gender dysphoria, as it is operationalised in the fifth edtion of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), remains a relatively 'rare' or 'uncommon' diagnosis, there is evidence that it has increased in the past couple of decades, perhaps reflected in the large increase in referral rates to specialised gender identity clinics. In childhood, the sex ratio continues to favour birth-assigned males, but in adolescents, there has been a recent inversion in the sex ratio from one favouring birth-assigned males to one favouring birth-assigned females. In both adolescents and adults, patterns of sexual orientation vary as a function of birth-assigned sex. Recent studies suggest that the prevalence of a self-reported transgender identity in children, adolescents and adults ranges from 0.5 to 1.3%, markedly higher than prevalence rates based on clinic-referred samples of adults. The stability of a self-reported transgender identity or a gender identity that departs from the traditional male-female binary among non-clinic-based populations remains unknown and requires further study.
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