Sex differences and the neurobiology of affective disorders

Relationship between sex biases in gene expression and sex biases in autism and Alzheimer's disease

BACKGROUND

Sex differences in the brain may play an important role in sex-differential prevalence of neuropsychiatric conditions.

METHODS

In order to understand the transcriptional basis of sex differences, we analyzed multiple, large-scale, human postmortem brain RNA-Seq datasets using both within-region and pan-regional frameworks.

RESULTS

We find evidence of sex-biased transcription in many autosomal genes, some of which provide evidence for pathways and cell population differences between chromosomally male and female individuals. These analyses also highlight regional differences in the extent of sex-differential gene expression. We observe an increase in specific neuronal transcripts in male brains and an increase in immune and glial function-related transcripts in female brains. Integration with single-nucleus data suggests this corresponds to sex differences in cellular states rather than cell abundance. Integration with case-control gene expression studies suggests a female molecular predisposition towards Alzheimer's disease, a female-biased disease. Autism, a male-biased diagnosis, does not exhibit a male predisposition pattern in our analysis.

CONCLUSION

Overall, these analyses highlight mechanisms by which sex differences may interact with sex-biased conditions in the brain. Furthermore, we provide region-specific analyses of sex differences in brain gene expression to enable additional studies at the interface of gene expression and diagnostic differences.

Applying the Research Domain Criteria to Rodent Studies of Sex Differences in Chronic Stress Susceptibility

Women have a 2-fold increased rate of stress-associated psychiatric disorders such as depression and anxiety, but the mechanisms that underlie this increased susceptibility remain incompletely understood. Historically, female subjects were excluded from preclinical studies and clinical trials. Additionally, chronic stress paradigms used to study psychiatric pathology in animal models were developed for use in males. However, recent changes in National Institutes of Health policy encourage inclusion of female subjects, and considerable work has been performed in recent years to understand biological sex differences that may underlie differences in susceptibility to chronic stress-associated psychiatric conditions. Here, we review the utility as well as current challenges of using the framework of the National Institute of Mental Health's Research Domain Criteria as a transdiagnostic approach to study sex differences in rodent models of chronic stress including recent progress in the study of sex differences in the neurobehavioral domains of negative valence, positive valence, cognition, social processes, and arousal.

Juvenile peripheral LPS exposure overrides female resilience to prenatal VPA effects on adult sociability in mice

Autism spectrum disorder (ASD) exhibits a gender bias, with boys more frequently affected than girls. Similarly, in mouse models induced by prenatal exposure to valproic acid (VPA), males typically display reduced sociability, while females are less affected. Although both males and females exhibit VPA effects on neuroinflammatory parameters, these effects are sex-specific. Notably, females exposed to VPA show increased microglia and astrocyte density during the juvenile period. We hypothesized that these distinct neuroinflammatory patterns contribute to the resilience of females to VPA. To investigate this hypothesis, we treated juvenile animals with intraperitoneal bacterial lipopolysaccharides (LPS), a treatment known to elicit brain neuroinflammation. We thus evaluated the impact of juvenile LPS-induced inflammation on adult sociability and neuroinflammation in female mice prenatally exposed to VPA. Our results demonstrate that VPA-LPS females exhibit social deficits in adulthood, overriding the resilience observed in VPA-saline littermates. Repetitive behavior and anxiety levels were not affected by either treatment. We also evaluated whether the effect on sociability was accompanied by heightened neuroinflammation in the cerebellum and hippocampus. Surprisingly, we observed reduced astrocyte and microglia density in the cerebellum of VPA-LPS animals. These findings shed light on the complex interactions between prenatal insults, juvenile inflammatory stimuli, and sex-specific vulnerability in ASD-related social deficits, providing insights into potential therapeutic interventions for ASD.

The pivotal role of the X-chromosome in the genetic architecture of the human brain

Genes on the X-chromosome are extensively expressed in the human brain. However, little is known for the X-chromosome's impact on the brain anatomy, microstructure, and functional network. We examined 1,045 complex brain imaging traits from 38,529 participants in the UK Biobank. We unveiled potential autosome-X-chromosome interactions, while proposing an atlas outlining dosage compensation (DC) for brain imaging traits. Through extensive association studies, we identified 72 genome-wide significant trait-locus pairs (including 29 new associations) that share genetic architectures with brain-related disorders, notably schizophrenia. Furthermore, we discovered unique sex-specific associations and assessed variations in genetic effects between sexes. Our research offers critical insights into the X-chromosome's role in the human brain, underscoring its contribution to the differences observed in brain structure and functionality between sexes.

A chromosome region linked to neurodevelopmental disorders acts in distinct neuronal circuits in males and females to control locomotor behavior

Biological sex shapes the manifestation and progression of neurodevelopmental disorders (NDDs). These disorders often demonstrate male-specific vulnerabilities; however, the identification of underlying mechanisms remains a significant challenge in the field. Hemideletion of the 16p11.2 region (16p11.2 del/+) is associated with NDDs, and mice modeling 16p11.2 del/+ exhibit sex-specific striatum-related phenotypes relevant to NDDs. Striatal circuits, crucial for locomotor control, consist of two distinct pathways: the direct and indirect pathways originating from D1 dopamine receptor (D1R) and D2 dopamine receptor (D2R) expressing spiny projection neurons (SPNs), respectively. In this study, we define the impact of 16p11.2 del/+ on striatal circuits in male and female mice. Using snRNA-seq, we identify sex- and cell type-specific transcriptomic changes in the D1- and D2-SPNs of 16p11.2 del/+ mice, indicating distinct transcriptomic signatures in D1-SPNs and D2-SPNs in males and females, with a ∼5-fold greater impact in males. Further pathway analysis reveals differential gene expression changes in 16p11.2 del/+ male mice linked to synaptic plasticity in D1- and D2-SPNs and GABA signaling pathway changes in D1-SPNs. Consistent with our snRNA-seq study revealing changes in GABA signaling pathways, we observe distinct changes in miniature inhibitory postsynaptic currents (mIPSCs) in D1- and D2-SPNs from 16p11.2 del/+ male mice. Behaviorally, we utilize conditional genetic approaches to introduce the hemideletion selectively in either D1- or D2-SPNs and find that conditional hemideletion of genes in the 16p11.2 region in D2-SPNs causes hyperactivity in male mice, but hemideletion in D1-SPNs does not. Within the striatum, hemideletion of genes in D2-SPNs in the dorsal lateral striatum leads to hyperactivity in males, demonstrating the importance of this striatal region. Interestingly, conditional 16p11.2 del/+ within the cortex drives hyperactivity in both sexes. Our work reveals that a locus linked to NDDs acts in different striatal circuits, selectively impacting behavior in a sex- and cell type-specific manner, providing new insight into male vulnerability for NDDs.

Highlights

- 16p11.2 hemideletion (16p11.2 del/+) induces sex- and cell type-specific transcriptomic signatures in spiny projection neurons (SPNs). - Transcriptomic changes in GABA signaling in D1-SPNs align with changes in inhibitory synapse function. - 16p11.2 del/+ in D2-SPNs causes hyperactivity in males but not females. - 16p11.2 del/+ in D2-SPNs in the dorsal lateral striatum drives hyperactivity in males. - 16p11.2 del/+ in cortex drives hyperactivity in both sexes.

Graphic abstract

Modeling brain sex in the limbic system as phenotype for female-prevalent mental disorders

BACKGROUND

Sex differences exist in the prevalence and clinical manifestation of several mental disorders, suggesting that sex-specific brain phenotypes may play key roles. Previous research used machine learning models to classify sex from imaging data of the whole brain and studied the association of class probabilities with mental health, potentially overlooking regional specific characteristics.

METHODS

We here investigated if a regionally constrained model of brain volumetric imaging data may provide estimates that are more sensitive to mental health than whole brain-based estimates. Given its known role in emotional processing and mood disorders, we focused on the limbic system. Using two different cohorts of healthy subjects, the Human Connectome Project and the Queensland Twin IMaging, we investigated sex differences and heritability of brain volumes of limbic structures compared to non-limbic structures, and subsequently applied regionally constrained machine learning models trained solely on limbic or non-limbic features. To investigate the biological underpinnings of such models, we assessed the heritability of the obtained sex class probability estimates, and we investigated the association with major depression diagnosis in an independent clinical sample. All analyses were performed both with and without controlling for estimated total intracranial volume (eTIV).

RESULTS

Limbic structures show greater sex differences and are more heritable compared to non-limbic structures in both analyses, with and without eTIV control. Consequently, machine learning models performed well at classifying sex based solely on limbic structures and achieved performance as high as those on non-limbic or whole brain data, despite the much smaller number of features in the limbic system. The resulting class probabilities were heritable, suggesting potentially meaningful underlying biological information. Applied to an independent population with major depressive disorder, we found that depression is associated with male-female class probabilities, with largest effects obtained using the limbic model. This association was significant for models not controlling for eTIV whereas in those controlling for eTIV the associations did not pass significance correction.

CONCLUSIONS

Overall, our results highlight the potential utility of regionally constrained models of brain sex to better understand the link between sex differences in the brain and mental disorders.

Outcome differences between males and females undergoing deep brain stimulation for treatment-resistant depression: systematic review and individual patient data meta-analysis

BACKGROUND

Treatment-resistant depression (TRD) occurs more commonly in women. Deep brain stimulation (DBS) is an emerging treatment for TRD, and its efficacy continues to be explored. However, differences in treatment outcomes between males and females have yet to be explored in formal analysis.

METHODS

A PRISMA-compliant systematic review of DBS for TRD studies was conducted. Patient-level data were independently extracted by two authors. Treatment response was defined as a 50 % or greater reduction in depression score. Percent change in depression scores by gender were evaluated using random-effects analyses.

RESULTS

Of 737 records, 19 studies (129 patients) met inclusion criteria. The mean reduction in depression score for females was 57.7 % (95 % CI, 64.33 %-51.13 %), whereas for males it was 35.2 % (95 % CI, 45.12 %-25.23 %) (p < 0.0001). Females were more likely to respond to DBS for TRD when compared to males (OR = 2.44, 95 % CI 1.06, 1.95). These differences varied in significance when stratified by DBS anatomical target, age, and timeframe for responder classification.

LIMITATIONS

Studies included were open-label trials with small sample sizes.

CONCLUSIONS

Our findings suggest that females with TRD respond at higher rates to DBS treatment than males. Further research is needed to elucidate the implications of these results, which may include connectomic sexual dimorphism, depression phenotype variations, or unrecognized symptom reporting differences. Methodological standardization of outcome scales, granular demographic data, and individual subject outcomes would allow for more robust comparisons between trials.

Chronic exposure to imipramine induces a switch from depression-like to mania-like behavior in female serotonin transporter knockout rats: Role of BDNF signaling in the infralimbic cortex

BACKGROUND

Bipolar disorder (BD) is a highly burdensome psychiatric disorder characterized by alternating states of mania and depression. A major challenge in the clinic is the switch from depression to mania, which is often observed in female BD patients during antidepressant treatment such as imipramine. However, the underlying neural basis is unclear.

METHODS

To investigate the potential neuronal pathways, serotonin transporter knockout (SERT KO) rats, an experimental model of female BD patients, were subjected to a battery of behavioral tests under chronic treatment of the antidepressant imipramine. In addition, the expression of brain-derived neurotrophic factor (BDNF) and its downstream signaling was examined in the prefrontal cortex.

RESULTS

Chronic exposure to imipramine reduced anxiety and sociability and problem-solving capacity, and increased thigmotaxis and day/night activity in all animals, but specifically in female SERT KO rats, compared to female wild-type (WT) rats. Further, we found an activation of BDNF-TrkB-Akt pathway signaling in the infralimbic, but not prelimbic, cortex after chronic imipramine treatment in SERT KO, but not WT, rats.

LIMITATIONS

Repeated testing behaviors could potentially affect the results. Additionally, the imipramine induced changes in behavior and in the BDNF system were measured in separate animals.

CONCLUSIONS

Our study indicates that female SERT KO rats, which mirror the female BD patients with the 5-HTTLPR s-allele, are at higher risk of a switch to mania-like behaviors under imipramine treatment. Activation of the BDNF-TrkB-Akt pathway in the infralimbic cortex might contribute to this phenotype, but causal evidence remains to be provided.

SIRT1 Coordinates Transcriptional Regulation of Neural Activity and Modulates Depression-Like Behaviors in the Nucleus Accumbens

BACKGROUND

Major depression and anxiety disorders are significant causes of disability and socioeconomic burden. Despite the prevalence and considerable impact of these affective disorders, their pathophysiology remains elusive. Thus, there is an urgent need to develop novel therapeutics for these conditions. We evaluated the role of SIRT1 in regulating dysfunctional processes of reward by using chronic social defeat stress to induce depression- and anxiety-like behaviors. Chronic social defeat stress induces physiological and behavioral changes that recapitulate depression-like symptomatology and alters gene expression programs in the nucleus accumbens, but cell type-specific changes in this critical structure remain largely unknown.

METHODS

We examined transcriptional profiles of D1-expressing medium spiny neurons (MSNs) lacking deacetylase activity of SIRT1 by RNA sequencing in a cell type-specific manner using the RiboTag line of mice. We analyzed differentially expressed genes using gene ontology tools including SynGO and EnrichR and further demonstrated functional changes in D1-MSN-specific SIRT1 knockout (KO) mice using electrophysiological and behavioral measurements.

RESULTS

RNA sequencing revealed altered transcriptional profiles of D1-MSNs lacking functional SIRT1 and showed specific changes in synaptic genes including glutamatergic and GABAergic (gamma-aminobutyric acidergic) receptors in D1-MSNs. These molecular changes may be associated with decreased excitatory and increased inhibitory neural activity in Sirt1 KO D1-MSNs, accompanied by morphological changes. Moreover, the D1-MSN-specific Sirt1 KO mice exhibited proresilient changes in anxiety- and depression-like behaviors.

CONCLUSIONS

SIRT1 coordinates excitatory and inhibitory synaptic genes to regulate the GABAergic output tone of D1-MSNs. These findings reveal a novel signaling pathway that has potential for the development of innovative treatments for affective disorders.

Ketamine produces no detectable long-term positive or negative effects on cognitive flexibility or reinforcement learning of male rats

RATIONALE

Patients with major depressive disorder (MDD) often experience abnormalities in behavioral adaptation following environmental changes (i.e., cognitive flexibility) and tend to undervalue positive outcomes but overvalue negative outcomes. The probabilistic reversal learning task (PRL) is used to study these deficits across species and to explore drugs that may have therapeutic value. Selective serotonin-reuptake inhibitors (SSRIs) have limited effectiveness in treating MDD and produce inconsistent effects in non-human versions of the PRL. As such, ketamine, a novel and potentially rapid-acting therapeutic, has begun to be examined using the PRL. Two previous studies examining the effects of ketamine in the PRL have shown conflicting results and only examined short-term effects of ketamine.

OBJECTIVE

This experiment examined PRL performance across a 2-week period following a single exposure to a ketamine dose that varied across groups.

METHODS

After five sessions of PRL training, groups of rats received an injection of either 0, 10, 20 or 30 mg/kg ketamine. One-hour post-injection, rats engaged in the PRL, and subsequently sessions continued daily for 2 weeks. Traditional behavioral and computational reinforcement learning-derived measures were examined.

RESULTS

Results showed that ketamine had acute effects 1-h post-injection, including a significant decrease in the value of the punishment learning rate. Beyond 1 h, ketamine produced no detectable improvements nor decrements in performance across 2 weeks.

CONCLUSION

Overall, the present results suggest that the range of ketamine doses examined do not have long-term positive or negative effects on cognitive flexibility or reward processing in healthy rats as measured by the PRL.

A Shared Multivariate Brain-Behavior Relationship in a Transdiagnostic Sample of Adolescents

BACKGROUND

Internalizing and externalizing psychopathology typically present in early childhood and can have negative implications on general functioning and quality of life. Prior work has linked increased psychopathology symptoms with altered brain structure. Multivariate analysis such as partial least squares correlation can help identify patterns of covariation between brain regions and psychopathology symptoms. This study examined the relationship between gray matter volume (GMV) and psychopathology symptoms in adolescents with various psychiatric diagnoses.

METHODS

Structural magnetic resonance imaging data were collected from 490 participants with various internalizing and externalizing diagnoses (197 female/293 male; age = 14.68 ± 2.35 years; IQ = 104.05 ± 13.11). Cortical and subcortical volumes were parcellated using the Desikan-Killiany atlas. Partial least squares correlation was used to identify multivariate linear relationships between GMV and the Strength and Difficulties Questionnaire difficulties domains (emotional, peer, conduct, and hyperactivity issues). Resampling approaches were used to determine significance (permutation test), stability (bootstrap resampling), and reproducibility (split-half resampling) of identified relationships.

RESULTS

We found a significant, stable, and largely reproducible dimension that linked lower Strength and Difficulties Questionnaire scores (less impairment) across all difficulties domains with greater widespread GMV (singular value = 1.17, accounts for 87.1% of the covariance; p < .001). This dimension emphasized the relationship between lower conduct problems and greater GMV in frontotemporal regions.

CONCLUSIONS

Our results indicate that the most significant and stable brain-behavior relationship in a transdiagnostic sample is a domain-general relationship, linking lower psychopathology symptom scores to greater global GMV. This finding suggests that a shared brain-behavior relationship may be present across adolescents with and without clinically significant psychopathology symptoms.

Prevalence of autoimmune diseases in functional neurological disorder: influence of psychiatric comorbidities and biological sex

BACKGROUND

Functional neurological disorder (FND) is a common and disabling neuropsychiatric condition, which disproportionally affects women compared with men. While the etiopathogenesis of this disorder remains elusive, immune dysregulation is emerging as one potential mechanism. To begin to understand the role of immune dysfunctions in FND, we assessed the prevalence of several common autoimmune diseases (ADs) in a large cohort of patients with FND and examined the influence of psychiatric comorbidities and biological sex.

METHODS

Using a large biorepository database (Mass General Brigham Biobank), we obtained demographic and clinical data of a cohort of 643 patients diagnosed with FND between January 2015 and December 2021. The proportion of ADs was calculated overall, by sex and by the presence of psychiatric comorbidities.

RESULTS

The overall prevalence of ADs in our sample was 41.9%, with connective tissue and autoimmune endocrine diseases being the most commonly observed ADs. Among patients with FND and ADs, 27.7% had ≥2 ADs and 8% met criteria for multiple autoimmune syndrome. Rates of ADs were significantly higher in subjects with comorbid major depressive disorder and post-traumatic stress disorder (p= 0.02). Women represented the largest proportion of patients with concurrent ADs, both in the overall sample and in the subgroups of interest (p's < 0.05).

CONCLUSIONS

This study is unique in providing evidence of an association between FND and ADs. Future studies are needed to investigate the mechanisms underlying this association and to understand whether FND is characterised by distinct dysregulations in immune response.

Track-by-Day: A standardized approach to estrous cycle monitoring in biobehavioral research

Despite known sex differences in brain function, female subjects are underrepresented in preclinical neuroscience research. This is driven in part by concerns about variability arising from estrous cycle-related hormone fluctuations, especially in fear- and anxiety-related research where there are conflicting reports as to whether and how the cycle influences behavior. The inconsistency may arise from a lack of common standards for tracking and reporting the cycle as opposed to inherent unpredictability in the cycle itself. The rat estrous cycle is conventionally tracked by assigning vaginal cytology smears to one of four qualitatively-defined stages. Although the cytology stages are of unequal length, the stage names are often, but not always, used to refer to the four cycle days. Subjective staging criteria and inconsistent use of terminology are not necessarily a problem in research on the cycle itself, but can lead to irreproducibility in neuroscience studies that treat the stages as independent grouping factors. We propose the explicit use of cycle days as independent variables, which we term Track-by-Day to differentiate it from traditional stage-based tracking, and that days be indexed to the only cytology feature that is a direct and rapid consequence of a hormonal event: a cornified cell layer formed in response to the pre-ovulatory 17β-estradiol peak. Here we demonstrate that cycle length is robustly regular with this method, and that the method outperforms traditional staging in detecting estrous cycle effects on Pavlovian fear conditioning and on a separate proxy for hormonal changes, uterine histology.

An X Chromosome Transcriptome Wide Association Study Implicates ARMCX6 in Alzheimer's Disease

Background

The X chromosome is often omitted in disease association studies despite containing thousands of genes that may provide insight into well-known sex differences in the risk of Alzheimer's disease (AD).

Objective

To model the expression of X chromosome genes and evaluate their impact on AD risk in a sex-stratified manner.

Methods

Using elastic net, we evaluated multiple modeling strategies in a set of 175 whole blood samples and 126 brain cortex samples, with whole genome sequencing and RNA-seq data. SNPs (MAF > 0.05) within the cis-regulatory window were used to train tissue-specific models of each gene. We apply the best models in both tissues to sex-stratified summary statistics from a meta-analysis of Alzheimer's Disease Genetics Consortium (ADGC) studies to identify AD-related genes on the X chromosome.

Results

Across different model parameters, sample sex, and tissue types, we modeled the expression of 217 genes (95 genes in blood and 135 genes in brain cortex). The average model R2 was 0.12 (range from 0.03 to 0.34). We also compared sex-stratified and sex-combined models on the X chromosome. We further investigated genes that escaped X chromosome inactivation (XCI) to determine if their genetic regulation patterns were distinct. We found ten genes associated with AD at p < 0.05, with only ARMCX6 in female brain cortex (p = 0.008) nearing the significance threshold after adjusting for multiple testing (α = 0.002).

Conclusions

We optimized the expression prediction of X chromosome genes, applied these models to sex-stratified AD GWAS summary statistics, and identified one putative AD risk gene, ARMCX6.

The role of the Toll like receptor 4 signaling in sex-specific persistency of depression-like behavior in response to chronic stress

Chronic stress is a major risk factor for Major Depressive Disorder (MDD), and it has been shown to impact the immune system and cause microglia activation in the medial prefrontal cortex (mPFC) involved in the pathogenesis of depression. The aim of this study is to further investigate cellular and molecular mechanisms underlying persistent depression behavior in sex specific manner, which is observed clinically. Here, we report that both male and female mice exhibited depression-like behavior following exposure to chronic stress. However, only female mice showed persistent depression-like behavior, which was associated with microglia activation in mPFC, characterized by distinctive alterations in the phenotype of microglia. Given these findings, to further investigate the underlying molecular mechanisms associated with persistent depression-like behavior and microglia activation in female mice, we used translating-ribosome affinity purification (TRAP). We find that Toll like receptor 4 (TLR4) signaling is casually related to persistent depression-like behavior in female mice. This is supported by the evidence that the fact that genetic ablation of TLR4 expression in microglia significantly reduced the persistent depression-like behavior to baseline levels in female mice. This study tentatively supports the hypothesis that the TLR4 signaling in microglia may be responsible for the sex differences in persistent depression-like behavior in female.

Associations among early life adversity, sleep disturbances, and depressive symptoms in adolescent females and males: a longitudinal investigation

BACKGROUND

Exposure to adversity early in life (ELA) has been associated with elevated risk for depression during adolescence, particularly for females; the mechanisms underlying this association, however, are poorly understood. One potential mechanism linking ELA and sex differences in depressive symptoms is sleep disturbances, which increase during adolescence and are more common in females. Here, we examined whether sleep disturbances mediate the association between ELA and increases in depressive symptoms during adolescence and whether this mediation differs by sex.

METHODS

224 (N = 132 females) youth were recruited at age 9-13 years and assessed every 2 years across three timepoints. At the first timepoint, we conducted extensive interviews about stressful events participants experienced; participants provided subjective severity ratings of events and we objectively scored the severity of each event. Self-reported sleep disturbances and depressive symptoms were assessed at all timepoints. We conducted linear mixed models to estimate both initial levels and changes in sleep disturbances and depressive symptoms, and moderated mediation analyses to test whether initial levels and/or changes in sleep disturbances mediated the association of ELA (objective and subjective) with increases in depressive symptoms across adolescence and whether the mediations differed by sex.

RESULTS

While higher initial levels and increases in sleep problems were uniquely associated with increases in depressive symptoms for males and females, they were related to ELA differently by sex. For females, greater ELA (both objectively and subjectively rated) was associated with higher initial levels of sleep problems, which in turn were associated with increases in depressive symptoms from early to late adolescence. In contrast, for males, ELA exposure was not associated with either initial levels of, or increases in, sleep problems.

CONCLUSIONS

These findings highlight the role of sleep disturbances during the transition to adolescence in mediating sex differences in the effects of ELA on depressive symptoms.

Sex matters: acute functional connectivity changes as markers of remission in late-life depression differ by sex

The efficacy of antidepressant treatment in late-life is modest, a problem magnified by an aging population and increased prevalence of depression. Understanding the neurobiological mechanisms of treatment response in late-life depression (LLD) is imperative. Despite established sex differences in depression and neural circuits, sex differences associated with fMRI markers of antidepressant treatment response are underexplored. In this analysis, we assess the role of sex on the relationship of acute functional connectivity changes with treatment response in LLD. Resting state fMRI scans were collected at baseline and day one of SSRI/SNRI treatment for 80 LLD participants. One-day changes in functional connectivity (differential connectivity) were related to remission status after 12 weeks. Sex differences in differential connectivity profiles that distinguished remitters from non-remitters were assessed. A random forest classifier was used to predict the remission status with models containing various combinations of demographic, clinical, symptomatological, and connectivity measures. Model performance was assessed with area under the curve, and variable importance was assessed with permutation importance. The differential connectivity profile associated with remission status differed significantly by sex. We observed evidence for a difference in one-day connectivity changes between remitters and non-remitters in males but not females. Additionally, prediction of remission was significantly improved in male-only and female-only models over pooled models. Predictions of treatment outcome based on early changes in functional connectivity show marked differences between sexes and should be considered in future MR-based treatment decision-making algorithms.

Sex differences in intrinsic functional cortical organization reflect differences in network topology rather than cortical morphometry

Brain size robustly differs between sexes. However, the consequences of this anatomical dimorphism on sex differences in intrinsic brain function remain unclear. We investigated the extent to which sex differences in intrinsic cortical functional organization may be explained by differences in cortical morphometry, namely brain size, microstructure, and the geodesic distances of connectivity profiles. For this, we computed a low dimensional representation of functional cortical organization, the sensory-association axis, and identified widespread sex differences. Contrary to our expectations, observed sex differences in functional organization were not fundamentally associated with differences in brain size, microstructural organization, or geodesic distances, despite these morphometric properties being per se associated with functional organization and differing between sexes. Instead, functional sex differences in the sensory-association axis were associated with differences in functional connectivity profiles and network topology. Collectively, our findings suggest that sex differences in functional cortical organization extend beyond sex differences in cortical morphometry.

Teaser

Investigating sex differences in functional cortical organization and their association to differences in cortical morphometry.

Quantitative and qualitative sex difference in habenula-induced inhibition of midbrain dopamine neurons in the rat

Introduction

Clinically relevant sex differences have been noted in a number of affective, behavioral, cognitive, and neurological health disorders. Midbrain dopamine neurons are implicated in several of these same disorders and consequently are under investigation for their potential role in the manifestation of these sex differences. The lateral habenula exerts significant inhibitory control over dopamine neuronal firing, yet little is known about sex differences in this particular neurocircuit.

Methods

We performed in vivo, single unit, extracellular recordings of dopamine neurons in female and male anesthetized rats in response to single pulse stimulation of the lateral habenula. In addition, we assessed baseline firing properties of lateral habenula neurons and, by immunochemical means, assessed the distribution of estrogen receptor alpha cells in the lateral habenula.

Results

Habenula-induced inhibition of dopamine neuronal firing is reduced in female rats relative to male rats. In addition, male rats had a higher prevalence of rebound excitation. Furthermore, the firing pattern of lateral habenula neurons was less variable in female rats, and female rats had a higher density of estrogen receptor alpha positive cells in the lateral habenula.

Discussion

We found that the dopamine neuronal response to habenular stimulation is both qualitatively and quantitatively different in female and male rats. These novel findings together with reports in the contemporary literature lead us to posit that the sex difference in dopamine inhibition seen here relate to differential firing properties of lateral habenula neurons resulting from the presence of sex hormones. Further work is needed to test this hypothesis, which may have implications for understanding the etiology of several mental health disorders including depression, schizophrenia, and addiction.

Psychological health among older adult women in the United States during the COVID-19 pandemic

This study examined differences in mental health in older adult women before versus during the COVID-19 pandemic. Participants who were community dwelling (N = 227) included n = 67 women aged 60-94 in the pre-pandemic group and n = 160 women aged 60-85 in the peri-pandemic group who completed self-report measures assessing mental health and quality of life (QOL). We compared mental health and QOL indices across the pre- and peri-pandemic groups. Results indicated that the peri-pandemic group reported higher anxiety (F = 4.94, p = .027) than the pre-pandemic group. No other significant differences emerged. Given the differential effects in this pandemic across SES, we conducted exploratory analyses investigating differences by income group. Controlling for education and race, within the pre-pandemic group, women with lower income reported worse physical function compared to the mid- and high-income groups. Within the peri-pandemic group, women with lower income reported worse anxiety, poorer sleep, and poorer QOL (physical function, role limitations due to physical problems, vitality, and pain) than high-income individuals. Overall, women who reported lower income reported worse mental health and QOL than those with high-income, especially during the pandemic. This indicates that income might act as a buffer for older women against negative psychological outcomes of the COVID-19 pandemic.

Killing pain?: a population-based registry study of the use of prescription analgesics, anxiolytics, and hypnotics among all children, adolescents and young adults in Norway from 2004 to 2019

The ongoing opioid epidemic has been a global concern for years, increasingly due to its heavy toll on young people's lives and prospects. Few studies have investigated trends in use of the wider range of drugs prescribed to alleviate pain, psychological distress and insomnia in children, adolescents and young adults. Our aim was to study dispensation as a proxy for use of prescription analgesics, anxiolytics and hypnotics across age groups (0-29 years) and sex over the last 15 years in a large, representative general population. The study used data from a nationwide prescription database, which included information on all drugs dispensed from any pharmacy in Norway from 2004 through 2019. Age-specific trends revealed that the prevalence of use among children and adolescents up to age 14 was consistently low, with the exception of a substantial increase in use of melatonin from age 5. From age 15-29, adolescents and young adults used more prescription drugs with increasing age at all time points, especially analgesics and drugs with higher potential for misuse. Time trends also revealed that children from age 5 were increasingly dispensed melatonin over time, while adolescents from age 15 were increasingly dispensed analgesics, including opioids, gabapentinoids and paracetamol. In contrast, use of benzodiazepines and z-hypnotics slightly declined in young adults over time. Although trends were similar for both sexes, females used more prescription drugs than their male peers overall. The upsurge in use of prescription analgesics, anxiolytics and hypnotics among young people is alarming.Trial registration The study is part of the overarching Killing Pain project. The rationale behind the Killing Pain research was pre-registered through ClinicalTrials.gov on April 7, 2020. Registration number NCT04336605; https://clinicaltrials.gov/ct2/show/record/NCT04336605 .

Premenstrual disorders and gender differences in adolescent mental health

BACKGROUND

Gender differences in mental health emerge in adolescence. The timing coincides with the development of premenstrual disorders (PMDs). Here, we examine the association between PMDs and adolescent mental health in the context of gender differences.

METHODS

A cross-sectional analysis comprising 21,239[10,563 (49.7 %) girls] individuals aged 10-19 years from the Santai Youth Mental Health Promotion Cohort in China. Possible PMDs, major depression disorder (MDD), general anxiety disorder (GAD), history of self-injury, and high suicide-risk status were surveyed using standard questionnaires. We used logistic regression to contrast the prevalence of outcomes between girls with and without PMDs, and boys.

RESULTS

The prevalence rates of possible MDD and GAD were comparable between girls without PMDs and boys [OR1.03 (0.96-1.11) and 0.99 (0.92-1.07)], whereas a higher burden was observed in girls with PMDs [OR4.76(4.31-5.26) and 3.86(3.50-4.27), respectively]. Moreover, MDD/GAD prevalence among premenarchal girls was comparable to their peer boys. Greater gender differences in self-injury and high suicide-risk status were also found for girls with PMDs [OR 4.70 (4.22-5.24) and 7.49 (6.6-8.5)] than that for girls without PMDs [OR1.45(1.33-1.59) and 1.81 (1.62-2.03)].

LIMITATION

Girls with PMDs may have overreported depressive and/or anxiety symptoms due to the overlap of symptomology.

CONCLUSIONS

The greater gender differences in adolescent mental ill-health among girls with PMDs lend support to the hypothesis that PMDs play an important role in the gender disparities in adolescent mental health, particularly in depression and anxiety.

Sex differences in depression, anxiety and health-promoting lifestyles among community residents: A network approach

BACKGROUND

Researchers have studied sex differences in typical depressive and anxiety symptoms and their cooccurrence. The World Health Organization (WHO) proposed a mental health promotion objective that suggests considering protective health-promoting factors when developing strategies for preventing mental disorders between sexes. From a network perspective, psychopathology is viewed as a result of interacting symptoms and influential factors. This study adopted network approach to investigate sex differences in health-promoting lifestyles (HPL) and the cooccurrence symptoms of communities in Shanghai. The aim is to provide health-promoting suggestions on better enhancing the life quality for community members.

METHODS

Depression, anxiety symptoms, and HPL were assessed with PHQ-9, GAD-7 and HPLP-II scales in 2420 adults (1411 females). Networks were constructed by Gaussian Graphical Models and the networks of two sexes using the Network Comparison Test.

RESULTS

Females scored significantly higher on PHQ-9 (p < 0.001) and GAD-7 (p < 0.001), and no differences were found between the two sexes in HPL scores. Restlessness and low energy yielded the highest strength centrality in the female network, while suicide ideation and restlessness were central in male network. Regarding protective HPL, physical activity and stress management were identified as the central mental health-promoting behaviours in female and male network, respectively. However, stress management was positively related to suicide ideation in the male network.

CONCLUSION

Communities should be aware of suicide ideation in males because of its high relationships with other symptoms and also provide stress management courses, especially for males. As for women, chronic energy deficiency deserves more attention for its high probability of cooccurrence with other symptoms in the network. Also, advocating physical activities may be particularly beneficial for the overall mental health among women. Future study should collect time-series data and analyze intraindividual networks to specify personalized health promoting strategies for each individual.

Profile and mental health characterization of childhood overprotection/overcontrol experiences among Chinese university students: a nationwide survey

Introduction

The childhood experiences of being overprotected and overcontrolled by family members have been suggested to be potentially traumatic. However, the possible associated factors of these experiences among young people are still not well studied. This study aimed to partly fill such gaps by a relatively large, nationwide survey of Chinese university students.

Methods

A total of 5,823 university students across nine different provinces in China were included by the convenience sampling method in the data analyses. All participants completed the overprotection/overcontrol (OP/OC) subscale in a recently developed 33-item childhood trauma questionnaire (CTQ- 33). Data were also collected on all participants' socio-demographic profiles and characterization of mental health. Binary logistic regression was conducted to investigate the associated socio-demographic and psychological factors of OP/ OC.

Results

The prevalence of childhood OP/OC was estimated as 15.63% (910/5,823) based on a cutoff OP/OC subscale score of  ≥ 13. Binary logistic regression suggested that being male, being a single child, having depression, having psychotic-like experiences, lower family functioning, and lower psychological resilience were independently associated with childhood OP/OC experiences (all corrected-p < 0.05). The OP/OC was also positively associated with all the other trauma subtypes (abuses and neglects) in the CTQ-33, while there are both shared and unique associated factors between the OP/OC and other trauma subtypes. Post-hoc analyses suggested that OP/OC experiences were associated with depression in only females and associated with anxiety in only males.

Discussion

Our results may provide initial evidence that childhood OP/OC experiences would have negative effects on young people's mental health which merits further investigations, especially in clinical populations.

Major Depression and Panic Disorder Associated with Implanon Implant: A Case Report

This report presents a case study of a patient who experienced depression and panic disorder symptoms associated with the use of Implanon, a contraceptive implant. This is a rare case of related prevalence data. The purpose of this report is to explore the potential relationship between Implanon and the development of these psychiatric conditions. The findings suggest a possible link between Implanon and the onset or exacerbation of depression and panic disorder symptoms. Further research is warranted to investigate the underlying mechanisms and determine the prevalence of such adverse effects.

Sex Differences in Brain Disorders

A remarkable feature of the brain is its sexual dimorphism. Sexual dimorphism in brain structure and function is associated with clinical implications documented previously in healthy individuals but also in those who suffer from various brain disorders. Sex-based differences concerning some features such as the risk, prevalence, age of onset, and symptomatology have been confirmed in a range of neurological and neuropsychiatric diseases. The mechanisms responsible for the establishment of sex-based differences between men and women are not fully understood. The present paper provides up-to-date data on sex-related dissimilarities observed in brain disorders and highlights the most relevant features that differ between males and females. The topic is very important as the recognition of disparities between the sexes might allow for the identification of therapeutic targets and pharmacological approaches for intractable neurological and neuropsychiatric disorders.

Association of two variable number of tandem repeats in the monoamine oxidase A gene promoter with suicide completion: The present study and meta-analysis

BACKGROUND

One potential cause of suicide is serotonergic dysfunction. Sex differences have been reported to modulate the effects of serotonergic polymorphisms. Monoamine oxidase A (MAOA) is an enzyme that degrades serotonin and is located on the X chromosome. A previous study indicated that the upstream (u) variable number of tandem repeat (VNTR) in the MAOA gene promoter may be associated with suicide. However, a meta-analysis showed that this polymorphism may not be related to suicide. According to a recent study, compared with the uVNTR, the distal (d)VNTR and the haplotypes of the two VNTRs modulate MAOA expression.

METHODS

We examined the two VNTRs in the MAOA gene promoter in 1007 subjects who committed suicide and 844 healthy controls. We analyzed the two VNTRs using fluorescence-based polymerase chain reaction assays. We conducted a meta-analysis for the two VNTRs to update it.

RESULTS

Our results demonstrated that neither the genotype-based associations nor allele/haplotype frequencies of the two VNTRs were significantly associated with suicide. In the meta-analysis, we did not indicate relationships between uVNTR and suicide nor did we identify articles analyzing dVNTR in suicide.

CONCLUSION

Overall, we did not find a relationship between the two VNTRs in the MAOA promoter and suicide completion; thus, warranting further studies are required.

GABA-ergic Modulators: New Therapeutic Approaches to Premenstrual Dysphoric Disorder

Premenstrual dysphoric disorder (PMDD) is characterized by the predictable onset of mood and physical symptoms secondary to gonadal steroid fluctuation during the luteal phase of the menstrual cycle. Although menstrual-related affective dysfunction is responsible for considerable functional impairment and reduction in quality of life worldwide, currently approved treatments for PMDD are suboptimal in their effectiveness. Research over the past two decades has suggested that the interaction between allopregnanolone, a neurosteroid derivative of progesterone, and the gamma-aminobutyric acid (GABA) system represents an important relationship underlying symptom genesis in reproductive-related mood disorders, including PMDD. The objective of this narrative review is to discuss the plausible link between changes in GABAergic transmission secondary to the fluctuation of allopregnanolone during the luteal phase and mood impairment in susceptible individuals. As part of this discussion, we explore promising findings from early clinical trials of several compounds that stabilize allopregnanolone signaling during the luteal phase, including dutasteride, a 5-alpha reductase inhibitor; isoallopregnanolone, a GABA-A modulating steroid antagonist; and ulipristal acetate, a selective progesterone receptor modulator. We then reflect on the implications of these therapeutic advances, including how they may promote our knowledge of affective regulation more generally. We conclude that these and other studies of PMDD may yield critical insight into the etiopathogenesis of affective disorders, considering that (1) symptoms in PMDD have a predictable onset and offset, allowing for examination of affective state kinetics, and (2) GABAergic interventions in PMDD can be used to better understand the relationship between mood states, network regulation, and the balance between excitatory and inhibitory signaling in the brain.

Ovariectomy in mice primes hippocampal microglia to exacerbate behavioral sickness responses

Estrogens are a group of steroid hormones that promote the development and maintenance of the female reproductive system and secondary sex characteristics. Estrogens also modulate immune responses; estrogen loss at menopause increases the risk of inflammatory disorders. Elevated inflammatory responses in the brain can lead to affective behavioral changes, which are characteristic of menopause. Thus, here we examined whether loss of estrogens sensitizes microglia, the primary innate immune cell of the brain, leading to changes in affective behaviors. To test this question, adult C57BL/6 mice underwent an ovariectomy to remove endogenous estrogens and then received estradiol hormone replacement or vehicle. After a one-month recovery, mice received an immune challenge with lipopolysaccharide (LPS) or vehicle control treatment and underwent behavioral testing. Ovariectomized, saline-treated mice exhibited reduced social investigation compared to sham-operated mice. Furthermore, ovariectomized mice that received LPS exhibited an exacerbated decrease in sucrose preference, which was ameliorated by estradiol replacement. These results indicate that ovariectomy modulates affective behaviors at baseline and in response to an inflammatory challenge. Ovariectomy-related behavioral changes were associated with downregulation of Cx3cr1, a microglial receptor that limits activation, suggesting that estrogen loss can disinhibit microglia to immune stimuli. Indeed, estradiol treatment reduced ovariectomy-induced increases in Il1b and Il6 expression after an immune challenge. Changes in microglial reactivity following ovariectomy are likely subtle, as overt changes in microglial morphology (e.g., soma size and branching) were limited. Collectively, these results suggest that a lack of estrogens may allow microglia to confer exaggerated neuroimmune responses, thereby raising vulnerability to adverse affective- and sickness-related behavioral changes.

Gender heterogeneity in the influencing factors for cerebral microbleeds in acute ischemic stroke patients

BACKGROUND

Cerebral microbleeds (CMBs) are common in acute ischemic stroke (AIS) patients. The presence of CMBs increases the risk of hemorrhagic transformation in AIS patients, and it is also closely associated with cognitive decline and even dementia. At present, there exist different opinions on the independent risk factors for CMBs, and there is no consensus on whether there are gender differences in -post-stroke CMB. Therefore, this study sought to investigate gender heterogeneity in the influencing factors for CMBs by studying male and female AIS patients.

METHODS

This was a China-based, Single-center, retrospective review of data from 482 AIS inpatients at the Neurology Department of Hebei General Hospital (NCT05882123). Both demographic and clinical data were collected from the study subjects. Different head magnetic resonance imaging sequences were used to assess the subjects' CMBs, white matter lesions, and old lacunar infarcts (LI). Various statistical methods, including the t-test, χ2 test, and logistic regression, were used to analyze the gender heterogeneity of the influencing factors for CMBs in AIS patients.

RESULTS

When compared with the male AIS patients, the female AIS patients were older and had higher total cholesterol, triglyceride, high-density lipoprotein, low-density lipoprotein, ApoA, ApoB, and fibrinogen levels. The female AIS patients also had higher National Institute of Health Stroke Scale scores and hypertension disease composition ratios. By contrast, the proportions of female AIS patients with a history of smoking and a history of alcohol consumption were both lower than the corresponding proportions of male AIS patients. These differences were all statistically significant (p < .05). There were no statistically significant differences in the incidence and severity of CMBs between the male and female AIS patients (χ2 ＝ 0.851, 3.092, p > .05). The univariate and multivariate stepwise logistic regression analyses confirmed that age (OR = 1.074, 95% CI: 1.013-1.139, p = .016) and old LI (OR = 4.295, 95% CI: 1.062-17.375, p = .041) were independent risk factors for comorbid CMBs in the female AIS patients, while blood glucose (OR = 0.692, 95% CI: 0.494-0.968, p = .031) was an independent protective factor for comorbid CMBs in the female AIS patients. However, these factors were not found to be independent risk or protective factors for comorbid CMBs in male AIS patients.

CONCLUSION

There are gender differences in the influencing factors for CMBs in AIS patients. Age, old LIs, and blood glucose are independent risk or protective factors for comorbid CMBs in female AIS patients, although they are not associated with the risk of developing CMBs in male AIS patients.

Bibliometric Analysis on GABA-A Receptors Research Based on CiteSpace and VOSviewer

Background

GABA-A receptors are the primary mediators of brain inhibitory neurotransmission. In the past years, many studies focused on this channel to decipher the pathogenesis of related diseases but lacked bibliometric analysis research. This study aims to explore the research status and identify the research trends of GABA-A receptor channels.

Methods

Publications related to GABA-A receptor channels were retrieved from the Web of Science Core Collection from 2012 to 2022. After screening, the VOSviewer 1.6.18 and Citespace 5.8 R3 were used for bibliometric analysis from journals, countries, institutions, authors, co-cited references and keywords.

Results

We included 12,124 publications in the field of GABA-A receptor channels for analysis. The data shows that although there was a slight decrease in annual publications from 2012 to 2021, it remained at a relatively high level. Most publications were in the domain of neuroscience. Additionally, the United States was the most prolific country, followed by China. Univ Toronto was the most productive institution, and James M Cook led essential findings in this field. Furthermore, brain activation, GABAAR subunits expression, modulation mechanism in pain and anxiety behaviors and GABA and dopamine were paid attention to by researchers. And top research frontiers were molecular docking, autoimmune encephalitic series, obesity, sex difference, diagnosis and management, EEG and KCC2.

Conclusion

Taken together, academic attention on GABA-A receptor channels was never neglected since 2012. Our analysis identified key information, such as core countries, institutions and authors in this field. Molecular docking, autoimmune encephalitic series, obesity, sex difference, diagnosis and management, EEG and KCC2 will be the future research direction.

Neuromedin B excites central lateral amygdala neurons and reduces cardiovascular output and fear-potentiated startle

Neuromedin B (NMB) and gastrin-releasing peptide (GRP) are the two mammalian analogs in the bombesin peptide family that exert a variety of actions including emotional processing, appetitive behaviors, cognition, and tumor growth. The bombesin-like peptides interact with three receptors: the NMB-preferring bombesin 1 (BB1) receptors, the GRP-preferring bombesin 2 (BB2) receptors and the orphan bombesin 3 (BB3) receptors. Whereas, injection of bombesin into the central amygdala reduces satiety and modulates blood pressure, the underlying cellular and molecular mechanisms have not been determined. As administration of bombesin induces the expression of Fos in the lateral nucleus of the central amygdala (CeL) which expresses BB1 receptors, we probed the effects of NMB on CeL neurons using in vitro and in vivo approaches. We showed that activation of the BB1 receptors increased action potential firing frequency recorded from CeL neurons via inhibition of the inwardly rectifying K+ (Kir) channels. Activities of phospholipase Cβ and protein kinase C were required, whereas intracellular Ca2+ release was unnecessary for BB1 receptor-elicited potentiation of neuronal excitability. Application of NMB directly into the CeA reduced blood pressure and heart rate and significantly reduced fear-potentiated startle. We may provide a cellular and molecular mechanism whereby bombesin-like peptides modulate anxiety and fear responses in the amygdala.

COVID-19 fear and anxiety as mediators in the relationship between repetitive negative thinking and psychopathology: a community-based study during the 2nd confinement in Portugal

Repetitive negative thinking is a cognitive dimension of the onset and maintenance of psychopathology, and increased levels of psychopathology have been observed during COVID-19 lockdowns. The role of fear of COVID-19 and COVID-19 anxiety has been poorly explored in terms of psychopathology during lockdowns due to the pandemic crisis. This study examines the mediating role of fear of COVID-19 and COVID-19 anxiety in the relationship between repetitive negative thinking and psychopathology during the second lockdown in Portugal. Participants completed a web survey that included a sociodemographic questionnaire, the Fear of COVID-19 Scale, the COVID-19 Anxiety Scale, the Persistent and Intrusive Negative Thoughts Scale, and the Depression, Anxiety, and Stress Scale - 21. The results showed a positive and significant correlation between all variables and identified fear of COVID-19 and COVID-19 anxiety as significant mediators in the relationship between repetitive negative thinking and psychopathology during the second lockdown in Portugal, after controlling for being isolated, being infected, and working in first line response of COVID-19. Overall, the current findings highlight the role of cognitive dimensions such as anxiety and fear in the context of COVID-19, nearly a year after the pandemic outbreak and after the release of a vaccine. Mental health programs should consider improving coping strategies for emotion regulation, particularly fear and anxiety, during major catastrophic health-related events.

Emotion dysregulation in relation to cannabis use and mental health among young adults

BACKGROUND

Emotion dysregulation (ED) is a transdiagnostic variable that accounts for the onset and maintenance of mental health disorders. The interplay between ED, cannabis use and mental health has not been appraised in the young adult population and whether there are sex-dependent effects has yet to be examined. This study looked at whether ED mediates the association between past-month cannabis use and mental health, while considering sex as a moderator.

METHODS

2,762 (64.2% women) undergraduate Spanish students completed an online battery. Among others, they fulfilled the Depression Anxiety Stress Scale-21 (DASS-21) and the Difficulties in Emotion Regulation Scale (DERS-28). A two-way ANOVA assessed the effects of sex and past-month cannabis use on participants' DASS-21 scores. A set of moderated mediations tested whether the indirect effect of past-month cannabis use on DASS-21 through DERS differed by sex.

RESULTS

Past-month cannabis female users showed higher levels of depression, anxiety and stress (M = 51.10, SD = 26.72) than did men [(M = 33.76, SD = 20.31); F(1, 2758) = 5.119, p =.024, η²p =.002]. In female young adults only, the effect of past-month cannabis use on mental health was mediated by ED (total score), non-acceptance of emotional responses, lack of emotional control, difficulties in engaging in goal-directed behavior, and lack of emotional clarity (all p's < 0.005) CONCLUSIONS: Findings indicate the importance of considering ED in assessment and intervention practices. Interventions targeting ED may be particularly effective for female young adult cannabis users.

New Pharmacological Approaches to the Management of Premenstrual Dysphoric Disorder

Premenstrual symptoms are experienced by many female individuals during their fertile age. Premenstrual dysphoric disorder (PMDD), a sex-specific mood disorder, affects about 5% of female individuals during the luteal phase of the menstrual cycle. Treatment with selective serotonin reuptake inhibitors represents a valid solution to manage PMDD for many, but not all, patients. Owing to maladaptive neural reactivity to gonadal hormone fluctuations, that is, the putative mechanism postulated to underlie PMDD, drugs suppressing or stabilizing such variations have been tested. Recently, a clinically significant reduction in the severity of the mental symptoms of PMDD was observed upon treatment with a selective progesterone receptor modulator (SPRM), as demonstrated when comparing ulipristal acetate with placebo in a randomised controlled trial. Stable and low progesterone levels, with maintained low-medium oestradiol levels, define the endocrine profile of this treatment. Importantly, the efficacy of SPRM treatment was accompanied by negligible side effects. These promising results represent a headway to understanding the mechanisms behind PMDD symptomatology and opening up new solutions in the management of PMDD. They also call for studies on the long-term efficacy, safety, and viability of SPRMs in female individuals during their fertile age to further support the development of targeted management of female's mental ill-health in relation to the menstrual cycle. The present overview thus seeks to inform about current and new pharmacological approaches to the management of premenstrual dysphoric disorder.

Effects of adenosine A2A receptors on cognitive function in health and disease

Adenosine A2A receptors have been studied extensively in the context of motor function and movement disorders such as Parkinson's disease. In addition to these roles, A2A receptors have also been increasingly implicated in cognitive function and cognitive impairments in diverse conditions, including Alzheimer's disease, schizophrenia, acute brain injury, and stress. We review the roles of A2A receptors in cognitive processes in health and disease, focusing primarily on the effects of reducing or enhancing A2A expression levels or activities in animal models. Studies reveal that A2A receptors in neurons and astrocytes modulate multiple aspects of cognitive function, including memory and motivation. Converging evidence also indicates that A2A receptor levels and activities are aberrantly increased in aging, acute brain injury, and chronic disorders, and these increases contribute to neurocognitive impairments. Therapeutically targeting A2A receptors with selective modulators may alleviate cognitive deficits in diverse neurological and neuropsychiatric conditions. Further research on the exact neural mechanisms of these effects as well as the efficacy of selective A2A modulators on cognitive alterations in humans are important areas for future investigation.

From helplessness to controllability: toward a neuroscience of resilience

"Learned helplessness" refers to debilitating outcomes, such as passivity and increased fear, that follow an uncontrollable adverse event, but do not when that event is controllable. The original explanation argued that when events are uncontrollable the animal learns that outcomes are independent of its behavior, and that this is the active ingredient in producing the effects. Controllable adverse events, in contrast, fail to produce these outcomes because they lack the active uncontrollability element. Recent work on the neural basis of helplessness, however, takes the opposite view. Prolonged exposure to aversive stimulation per se produces the debilitation by potent activation of serotonergic neurons in the brainstem dorsal raphe nucleus. Debilitation is prevented with an instrumental controlling response, which activates prefrontal circuitry detecting control and subsequently blunting the dorsal raphe nucleus response. Furthermore, learning control alters the prefrontal response to future adverse events, thereby preventing debilitation and producing long-term resiliency. The general implications of these neuroscience findings may apply to psychological therapy and prevention, in particular by suggesting the importance of cognitions and control, rather than habits of control.

Fronto-amygdala resting state functional connectivity is associated with anxiety symptoms among adolescent girls more advanced in pubertal maturation

Early adolescence, with the onset of puberty, is an important period when sex differences in anxiety emerge, with girls reporting significantly higher anxiety symptoms than boys. This study examined the role of puberty on fronto-amygdala functional connectivity and risk of anxiety symptoms in 70 girls (age 11-13) who completed a resting state fMRI scan, self-report measures of anxiety symptoms and pubertal status, and provided basal testosterone levels (64 girls). Resting state fMRI data were preprocessed using fMRIPrep and connectivity indices were extracted from ventromedial prefrontal cortex (vmPFC) and amygdala regions-of-interest. We tested moderated mediation models and hypothesized that vmPFC-amygdala would mediate the relation between three indices of puberty (testosterone and adrenarcheal/gonadarcheal development) and anxiety, with puberty moderating the relation between connectivity and anxiety. Results showed a significant moderation effect of testosterone and adrenarcheal development in the right amygdala and a rostral/dorsal area of the vmPFC and of gonadarcheal development in the left amygdala and a medial area of the vmPFC on anxiety symptoms. Simple slope analyses showed that vmPFC-amygdala connectivity was negatively associated with anxiety only in girls more advanced in puberty suggesting that sensitivity to the effects of puberty on fronto-amygdala function could contribute to risk for anxiety disorders among adolescent girls.

Understanding the Mechanisms and Treatment of Heart Failure: Quantitative Systems Pharmacology Models with a Focus on SGLT2 Inhibitors and Sex-Specific Differences

Heart failure (HF), which is a major clinical and public health challenge, commonly develops when the myocardial muscle is unable to pump an adequate amount of blood at typical cardiac pressures to fulfill the body's metabolic needs, and compensatory mechanisms are compromised or fail to adjust. Treatments consist of targeting the maladaptive response of the neurohormonal system, thereby decreasing symptoms by relieving congestion. Sodium-glucose co-transporter 2 (SGLT2) inhibitors, which are a recent antihyperglycemic drug, have been found to significantly improve HF complications and mortality. They act through many pleiotropic effects, and show better improvements compared to others existing pharmacological therapies. Mathematical modeling is a tool used to describe the pathophysiological processes of the disease, quantify clinically relevant outcomes in response to therapies, and provide a predictive framework to improve therapeutic scheduling and strategies. In this review, we describe the pathophysiology of HF, its treatment, and how an integrated mathematical model of the cardiorenal system was built to capture body fluid and solute homeostasis. We also provide insights into sex-specific differences between males and females, thereby encouraging the development of more effective sex-based therapies in the case of heart failure.

Sex-related differences in endogenous pituitary adenylate cyclase-activating polypeptide (PACAP) in the thalamic paraventricular nucleus: Implications for addiction neuroscience

Males and females exhibit differences in motivated and affective behavior; however, the neural substrates underlying these differences remain poorly understood. In the paraventricular nucleus of the thalamus (PVT), sex-related differences in neuronal activity have been identified in response to motivated behavior tasks and affective challenges. Within the PVT, the neuropeptide, pituitary adenylate cyclase-activating polypeptide (PACAP), is highly expressed and is also involved in motivated and affective behavior. The purpose of this study was to compare the expression of PACAP mRNA and peptide in the PVT of males and females. Analysis with quantitative real-time PCR in mice revealed that females had significantly higher levels of PACAP mRNA than males in the whole PVT, but no differences in the neuropeptides enkephalin or corticotropin releasing factor (CRF) in this brain region. While in rats, females demonstrated a trend for greater gene expression than males in the anterior/middle and middle/posterior PVT, they again showed no differences in enkephalin or CRF. Analysis with immunofluorescent histochemistry revealed that female mice had significantly more PACAP-containing cells than males as a function of area throughout the PVT, and that female rats had significantly more PACAP-27 and PACAP-38-containing cells than males, both as a percentage of total cells and as a function of PVT area. For PACAP-27, this specifically occurred in the anterior PVT, and for PACAP-38, it occurred throughout the anterior, middle, and posterior PVT. These results suggest that sex-related differences in PVT PACAP may underly some of the established sex-related differences in motivated and affective behavior.

Sex effects in the interaction of acute stress and pain perception

ABSTRACT

A reciprocity between the stress and the pain system is recognized; however, the manner by which sex affects this reciprocity is unclear. Understanding the interactions of stress, pain, and sex may shed light on the apparent women's vulnerability to chronic pain, which often coexists with increased distress, and to affective disorders, which often coexist with chronic pain. The study's aim was to examine the effect of acute, validated, psychosocial stress on pain perception and modulation of women and men in a controlled manner. Participants were 82 women and 66 men. Heat-pain threshold, heat-pain tolerance, and pain modulation by temporal summation of pain (TSP), and pain adaptation were measured before and after exposure to the Montreal Imaging Stress Task (MIST) or to a sham task. The stress response was verified by perceived ratings of stress and anxiety, autonomic variables, and salivary cortisol. A significant stress response was obtained by the MIST among both sexes; however, women displayed a greater increase in perceived distress, and men displayed a greater increase in cortisol. Among women, TSP decreased and pain adaptation increased following the MIST, responses that were predicted by perceived distress levels. Among men, TSP increased following the MIST but was not predicted by the stress variables. In conclusion, acute stress manipulation seems to differentially affect both stress and pain responses of women and men: women exhibited stress-induced antinociception and men exhibited stress-induced pronociception. Higher perceived stress levels among women may trigger a temporary increase in pain inhibition mechanisms to serve evolutionary purposes.

Gender and sex in eating disorders: A narrative review of the current state of knowledge, research gaps, and recommendations

INTRODUCTION

Eating disorders (EDs) have long been considered conditions exclusively affecting women, and studies in the ED field regularly exclude men. Research efforts are needed to better understand the role of gender and sex in EDs. This review describes the role of gender and sex in the development of EDs from a biopsychosocial perspective.

METHODS

The primary hypothesis of this narrative review is that gender and sex interact to influence ED risk. The literature review was conducted using the PubMed database.

RESULTS

This review first presents the general characteristics and prevalence of EDs according to gender and sex. Next, neurodevelopmental processes, neurobiology, gender roles, body image, and the minority stress model are addressed. Lastly, research perspectives to better include gender and sex in the field of EDs are discussed (e.g., representation of gender and sex diversities, development of appropriate assessment tools, and increasing awareness).

CONCLUSION

Although substantial knowledge gaps remain, there is a growing recognition of the importance of integrating gender and sex in ED research that holds promise for further development in the field.

Sex-Determined Alteration of Frontal Electroencephalographic (EEG) Activity in Social Presence

This study represents a follow-up event-related potential (ERP) analysis of a prior investigation. The previous results showed that participants had most negative-tending ERPs in the mid-frontal brain region during exposure to neutral emotion pictures (compared to negative and positive pictures) while being accompanied by a significant other person (social presence condition). The present analysis aimed at investigating potential sex differences related to this phenomenon. Female and male participants' brain activity data from the previous study were analyzed separately for one representative mid-frontal electrode location selected on the basis of having the highest significance level. As a result, only female participants showed significantly more negative-tending potentials in response to neutral pictures, compared to both other emotion categories (positive and negative) in the social presence condition. This was not found in male participants. The respective ERP effect was most dominant at 838 ms post stimulus onset, which is slightly later than the effect found in the prior study. However, this result is interpreted as evidence that the general effect from the prior study can be understood as a largely female phenomenon. In line with the prior study, the present results are interpreted as a predominantly female activation in the mid-frontal brain region in response to neutral picture stimuli while being accompanied by a significant other person (social presence condition). Although only speculative, this would align with previous studies demonstrating sex-related hormonal and structural differences in the anterior cingulate cortex (ACC). In general, ACC activation has been associated with an integrative weighting function in ambiguous social settings, which makes sense given the ambiguous nature of neutral pictures in combination with a social presence condition.

Vicarious Social Defeat Increases Conditioned Rewarding Effects of Cocaine and Ethanol Intake in Female Mice

Stress is a critical factor in the development of mood and drug use disorders. The social defeat model is not appropriate for female rodents due to their low level of aggression. Therefore, a robust female model of social stress needs to be developed and validated. The aim of the present study was to unravel the long-lasting effects of vicarious social defeat (VSD) on the conditioned rewarding effects of cocaine and ethanol intake in female mice. Although VSD seems to be a good model for inducing behavioral and physiologic endophenotypes induced by stress, there are no studies to date that characterize the effect of VSD on cocaine or alcohol use. The results confirm that VSD females showed an increase in corticosterone levels after a vicarious experience while also displaying an increase in anxiety- and anhedonic-like behaviors. Three weeks after the last VSD, vicariously defeated female mice showed an increased developed preference for a non-effective dose of cocaine in the conditioned place preference (CPP) paradigm and showed an increase in ethanol intake. Our results suggest that female mice vicariously experience a state of distress through the social observation of others suffering from adverse events, confirming the use of VSD as a valid model to study the response to social stress in females. The fact that VSD in females induced a comparable behavioral phenotype to that observed in physically defeated males could indicate a relationship with the higher rate of psychopathologies observed in women. Notwithstanding, more studies are needed to dissect the neurobiological and behavioral peculiarities of the female response to social stress.

Elevated prefrontal dopamine interferes with the stress-buffering properties of behavioral control in female rats

Stress-linked disorders are more prevalent in women than in men and differ in their clinical presentation. Thus, investigating sex differences in factors that promote susceptibility or resilience to stress outcomes, and the circuit elements that mediate their effects, is important. In male rats, instrumental control over stressors engages a corticostriatal system involving the prelimbic cortex (PL) and dorsomedial striatum (DMS) that prevent many of the sequelae of stress exposure. Interestingly, control does not buffer against stress outcomes in females, and here, we provide evidence that the instrumental controlling response in females is supported instead by the dorsolateral striatum (DLS). Additionally, we used in vivo microdialysis, fluorescent in situ hybridization, and receptor subtype pharmacology to examine the contribution of prefrontal dopamine (DA) to the differential impact of behavioral control. Although both sexes preferentially expressed D1 receptor mRNA in PL GABAergic neurons, there were robust sex differences in the dynamic properties of prefrontal DA during controllable stress. Behavioral control potently attenuated stress-induced DA efflux in males, but not females, who showed a sustained DA increase throughout the entire stress session. Importantly, PL D1 receptor blockade (SCH 23390) shifted the proportion of striatal activity from the DLS to the DMS in females and produced the protective effects of behavioral control. These findings suggest a sex-selective mechanism in which elevated DA in the PL biases instrumental responding towards prefrontal-independent striatal circuitry, thereby eliminating the protective impact of coping with stress.

Sex- and exposure age-dependent effects of adolescent stress on ventral tegmental area dopamine system and its afferent regulators

Adolescent stress is a risk factor for schizophrenia. Emerging evidence suggests that age-dependent sensitive windows for childhood trauma are associated more strongly with adult psychosis, but the neurobiological basis and potential sex differences are unknown.Using in vivo electrophysiology and immunohistology in rats, we systematically compared the effects of two age-defined adolescent stress paradigms, prepubertal (postnatal day [PD] 21-30; PreP-S) and postpubertal (PD41-50; PostP-S) foot-shock and restraint combined stress, on ventral tegmental area (VTA) dopaminergic activity, pyramidal neuron activity in the ventral hippocampus (vHipp) and the basolateral amygdala (BLA), corticoamygdalar functional inhibitory control, and vHipp and BLA parvalbumin interneuron (PVI) impairments. These endpoints were selected based on their well-documented roles in the pathophysiology of psychosis.Overall, we found distinct sex- and exposure age-dependent stress vulnerability. Specifically, while males were selectively vulnerable to PreP-S-induced adult VTA dopamine neuron and vHipp hyperactivities, females were selectively vulnerable to PostP-S. These male selective PreP-S effects were correlated with stress-induced aberrant persistent BLA hyperactivity, dysfunctional prefrontal inhibitory control of BLA neurons, and vHipp/BLA PVI impairments. In contrast, female PostP-S only produced vHipp PVI impairments in adults, with the BLA structure and functions largely unaffected.Our results indicated distinct adolescent-sensitive periods during which stress can sex-dependently confer maximal risks to corticolimbic systems to drive dopamine hyperactivity, which provide critical insights into the neurobiological basis for sex-biased stress-related psychopathologies emphasizing but not limited to schizophrenia. Furthermore, our work also provides a framework for future translational research on age-sensitive targeted interventions.

Sexually dimorphic effects of estrogen receptor 2 deletion in the dorsal raphe nucleus on emotional behaviors

Sex differences in emotional behaviors and affective disorders have been widely noted, of which sexually dimorphic secretion of gonadal steroid hormones such as estrogen is suspected to play a role. However, the underlying neural mechanisms remain poorly understood. We noted that the expression of estrogen receptor 2 (Esr2, or ERβ), a key mediator of estrogen signaling in the brain, was enriched in the dorsal raphe nucleus (DRN), a region involved in emotion regulation. To investigate whether DRN Esr2 expression confers sex-specific susceptibility or vulnerability in emotional behaviors, we generated a conditional allele of Esr2 that allowed for site-specific deletion of Esr2 in the DRN via local injection of Cre-expressing viruses. DRN-specific Esr2 deletion mildly increased anxiety behaviors in females, as shown by decreased time spent in the center zone of an open field in knockout females. By contrast, DRN Esr2 deletion had no effects on anxiety levels in males, as demonstrated by knockout males spending comparable time in the center zone of an open field and open arms of an elevated-plus maze. Furthermore, in the tail suspension test, DRN Esr2 deletion reduced immobility, a depression-like behavior, in a male-biased manner. Together, these results reveal sex-specific functions of DRN Esr2 in regulating emotional behaviors and suggest targeted manipulation of DRN Esr2 signaling as a potential therapeutic strategy to treat sex-biased affective disorders.

Validation of the Arabic version of the 35-item TEMPS-M in a community sample of adults

BACKGROUND

To our knowledge, no brief version of the Temperament Evaluation in Memphis Pisa and San Diego (TEMPS-M) is available so far in the Arabic language, which might have resulted in limited research in this field from Arab countries. We aimed through this study to validate the 35-item TEMPS-M into the Arabic language in a sample of non-clinical Lebanese adults.

METHODS

We used an online cross-sectional survey targeting non-clinical Lebanese adults from the general population. A confirmatory factor analysis was conducted to test the factorial structure of the TEMPS-M.

RESULTS

All five temperament subscales achieved good/very good internal consistencies in the present study (depressive: α = 0.78, cyclothymic: α = 0.86, hyperthymic: α = 0.83, irritable: α = 0.87, and anxious: α = 0.87). The five-factor solution of the TEMPS-M displayed a good CFI of 0.94, TLI of .94 and a GFI of .95, but a poor RMSEA of .10 [90% CI .10, .11]. The five affective temperaments showed positive correlations with personality dysfunction domains, thus attesting for convergent validity. In addition, positive correlations between all affective temperament dimensions and anxiety/depression scores were found. We also tested for gender invariance, and found that configural, metric, and scalar invariance were supported across gender.

CONCLUSION

Our data suggest that the psychometric properties of the Arabic TEMPS-M are good. Making this scale available in Arabic will hopefully encourage Arab researchers to investigate this under-explored topic in their countries, and advance knowledge on how culture impacts the prevalence, development and course of temperament.

Sex Differences in Depression and Anxiety

Depression and anxiety disorders carry a tremendous worldwide burden and emerge as a significant cause of disability among western societies. Both disorders are known to disproportionally affect women, as they are twice more likely to be diagnosed and moreover, they are also prone to suffer from female-specific mood disorders. Importantly, the prevalence of these affective disorders has notably risen after the COVID pandemic, especially in women. In this chapter, we describe factors that are possibly contributing to the expression of such sex differences in depression and anxiety. For this, we overview the effect of transcriptomic and genetic factors, the immune system, neuroendocrine aspects, and cognition. Furthermore, we also provide evidence of sex differences in antidepressant response and their causes. Finally, we emphasize the importance to consider sex as a biological variable in preclinical and clinical research, which may facilitate the discovery and development of new and more efficacious antidepressant and anxiolytic pharmacotherapies for both women and men.

Fear of COVID-19 and Related Factors in Emergency Department Patients

This study was aimed to determine the fear of COVID-19 and related factors in patients. This study was conducted with 639 patients who were admitted to the emergency department. Data were collected using the sociodemographic characteristics form, Fear of COVID-19 scale (FCV-19S). The data were evaluated with Student's t-test to compare two groups and one-way ANOVA and post hoc Tukey's honestly significant difference (HSD) more than two groups. Multiple linear regression analysis was used to determine the relationship between dependent and independent variables. The mean age of patients was 46.12 ± 17.02, 53.4% were male, 70.7% were married, 42.4% had a chronic disease, 18.3% stated that they had symptoms of COVID-19, and 38.0% stated that they experienced economic difficulties due to COVID-19. The COVID-19 fear scores were significantly higher in 57 ages and over, female, had lung disease, had COVID-19 symptoms, and had children. Having a lung disease, female gender, and fear of COVID-19 were statistically significantly correlated with FCV-19S scores. As a result, it was determined that patients admitted to the emergency department had fear of COVID-19. Further research is recommended to support our study findings. As an emergency nurse, strategies must be developed to cope with these fears.