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Ansari MA, Naqvi HA, Khidri FF, Rajput AH, Mahmood A, Waryah AM. Gene-gene and gene-environmental interaction of dopaminergic system genes in Pakistani children with attention deficit hyperactivity disorder. Saudi J Biol Sci 2024; 31:104045. [PMID: 39050560 PMCID: PMC11268355 DOI: 10.1016/j.sjbs.2024.104045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Revised: 06/07/2024] [Accepted: 06/07/2024] [Indexed: 07/27/2024] Open
Abstract
Background Attention deficit hyperactivity disorder (ADHD) is a neurodevelopmental disorder influenced by genetic and environmental factors. This study examined the specific gene variants, dopamine transporter 1 (DAT1) rs6350, dopamine receptor D3 (DRD3) rs6280, dopamine receptor D2 (DRD2) rs6277, and catechol-O-methyltransferase (COMT) rs4633, in relation to ADHD among Pakistani children by exploring the potential gene-gene and gene-environment interactions. Methods A total of 100 cases of ADHD and 100 healthy children were recruited. The tetra-primer amplification refractory mutation system (ARMS) assays were designed for genotyping the selected variants in both groups, and their association with ADHD was determined in different genetic models. Gene-gene and gene-environmental interactions were determined by the multifactor dimensionality reduction (MDR) method. Results The DAT1 rs6350 SNV AA genotype showed a significantly increased risk for ADHD in the codominant and recessive models. Conversely, the AG genotype demonstrated a protective factor for ADHD in the codominant and overdominant models. The DRD3 rs6280 T allele exhibited a decreased risk for ADHD, and the TT genotype showed a reduced risk in the recessive and log-additive models. No association between the DRD2 rs6277 and COMT rs4633 SNVs with ADHD was found in our population. The MDR analysis of the best three-fold interaction model showed redundancy between DAT1 rs6350 and DRD3 rs6280; however, the risk was increased with the gender variable, which showed a weak synergistic interaction with these SNVs. Conclusion Genes associated with dopaminergic neurotransmission may contribute to the occurrence of ADHD. Furthermore, gene-gene and gene-environmental interactions may increase ADHD susceptibility.
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Affiliation(s)
- Moin Ahmed Ansari
- Institute of Biotechnology and Genetic Engineering, University of Sindh, Jamshoro, Pakistan
- Department of Molecular Biology and Genetics, Liaquat University of Medical and Health Sciences, Jamshoro, Pakistan
- Department of Psychiatry, Liaquat University of Medical and Health Sciences, Jamshoro, Pakistan
| | - Habib Ahmed Naqvi
- Institute of Biotechnology and Genetic Engineering, University of Sindh, Jamshoro, Pakistan
| | - Feriha Fatima Khidri
- Department of Molecular Biology and Genetics, Liaquat University of Medical and Health Sciences, Jamshoro, Pakistan
- Department of Biochemistry, Bilawal Medical College, Liaquat University of Medical and Health Sciences, Jamshoro, Pakistan
| | - Aatir Hanif Rajput
- Department of Psychiatry, Liaquat University of Medical and Health Sciences, Jamshoro, Pakistan
| | - Ambar Mahmood
- Department of Molecular Biology and Genetics, Liaquat University of Medical and Health Sciences, Jamshoro, Pakistan
| | - Ali Muhammad Waryah
- Department of Molecular Biology and Genetics, Liaquat University of Medical and Health Sciences, Jamshoro, Pakistan
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Caputi V, Hill L, Figueiredo M, Popov J, Hartung E, Margolis KG, Baskaran K, Joharapurkar P, Moshkovich M, Pai N. Functional contribution of the intestinal microbiome in autism spectrum disorder, attention deficit hyperactivity disorder, and Rett syndrome: a systematic review of pediatric and adult studies. Front Neurosci 2024; 18:1341656. [PMID: 38516317 PMCID: PMC10954784 DOI: 10.3389/fnins.2024.1341656] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Accepted: 02/02/2024] [Indexed: 03/23/2024] Open
Abstract
Introduction Critical phases of neurodevelopment and gut microbiota diversification occur in early life and both processes are impacted by genetic and environmental factors. Recent studies have shown the presence of gut microbiota alterations in neurodevelopmental disorders. Here we performed a systematic review of alterations of the intestinal microbiota composition and function in pediatric and adult patients affected by autism spectrum disorder (ASD), attention-deficit/hyperactivity disorder (ADHD), and Rett syndrome (RETT). Methods We searched selected keywords in the online databases of PubMed, Cochrane, and OVID (January 1980 to December 2021) with secondary review of references of eligible articles. Two reviewers independently performed critical appraisals on the included articles using the Critical Appraisal Skills Program for each study design. Results Our systematic review identified 18, 7, and 3 original articles describing intestinal microbiota profiles in ASD, ADHD, and RETT, respectively. Decreased Firmicutes and increased Bacteroidetes were observed in the gut microbiota of individuals affected by ASD and ADHD. Proinflammatory cytokines, short-chain fatty acids and neurotransmitter levels were altered in ASD and RETT. Constipation and visceral pain were related to changes in the gut microbiota in patients affected by ASD and RETT. Hyperactivity and impulsivity were negatively correlated with Faecalibacterium (phylum Firmicutes) and positively correlated with Bacteroides sp. (phylum Bacteroidetes) in ADHD subjects. Five studies explored microbiota-or diet-targeted interventions in ASD and ADHD. Probiotic treatments with Lactobacillus sp. and fecal microbiota transplantation from healthy donors reduced constipation and ameliorated ASD symptoms in affected children. Perinatal administration of Lactobacillus sp. prevented the onset of Asperger and ADHD symptoms in adolescence. Micronutrient supplementation improved disease symptomatology in ADHD without causing significant changes in microbiota communities' composition. Discussion Several discrepancies were found among the included studies, primarily due to sample size, variations in dietary practices, and a high prevalence of functional gastrointestinal symptoms. Further studies employing longitudinal study designs, larger sample sizes and multi-omics technologies are warranted to identify the functional contribution of the intestinal microbiota in developmental trajectories of the human brain and neurobehavior. Systematic review registration https://clinicaltrials.gov/, CRD42020158734.
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Affiliation(s)
- Valentina Caputi
- Poultry Production and Product Safety Research Unit, Agricultural Research Service, United States Department of Agriculture, Fayetteville, AR, United States
| | - Lee Hill
- Department of Pediatrics, Faculty of Health Sciences, McMaster University, Hamilton, ON, Canada
- Department of Pediatrics, Research Institute of the McGill University Health Centre, Montreal, QC, Canada
| | - Melanie Figueiredo
- Department of Pediatrics, Faculty of Health Sciences, McMaster University, Hamilton, ON, Canada
- Temerty Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Jelena Popov
- Department of Pediatrics, Faculty of Health Sciences, McMaster University, Hamilton, ON, Canada
- Harvard Medical School, Boston, MA, United States
- Boston Children’s Hospital, Boston, MA, United States
| | - Emily Hartung
- Department of Pediatrics, Faculty of Health Sciences, McMaster University, Hamilton, ON, Canada
- Department of Biochemistry and Biomedical Sciences, Faculty of Science, McMaster University, Hamilton, ON, Canada
| | - Kara Gross Margolis
- Department of Pediatrics, New York University Grossman School of Medicine, New York, NY, United States
- New York University Pain Research Center, New York, NY, United States
- New York University College of Dentistry, New York, NY, United States
| | - Kanish Baskaran
- Department of Pediatrics, Faculty of Health Sciences, McMaster University, Hamilton, ON, Canada
- Temerty Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Papiha Joharapurkar
- Department of Pediatrics, Faculty of Health Sciences, McMaster University, Hamilton, ON, Canada
| | - Michal Moshkovich
- Department of Pediatrics, Faculty of Health Sciences, McMaster University, Hamilton, ON, Canada
- Temerty Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Nikhil Pai
- Department of Pediatrics, Faculty of Health Sciences, McMaster University, Hamilton, ON, Canada
- Division of Gastroenterology, Hepatology and Nutrition, McMaster Children’s Hospital, Hamilton, ON, Canada
- Department of Pediatrics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, United States
- Division of Gastroenterology, Hepatology, and Nutrition, the Children’s Hospital of Philadelphia, Philadelphia, PA, United States
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Kant T, Koyama E, Zai CC, Sanches M, Beitchman JH, Kennedy JL. COMT Val/Met, stressful life events and externalizing behaviors in youth: A longitudinal study from the ABCD sample. Heliyon 2023; 9:e21126. [PMID: 38027832 PMCID: PMC10665666 DOI: 10.1016/j.heliyon.2023.e21126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Revised: 08/08/2023] [Accepted: 10/16/2023] [Indexed: 12/01/2023] Open
Abstract
Early adolescence is a crucial time for understanding and detecting the risk factors that may influence youth externalizing/disruptive behaviors and disorders. Previous literature reported evidence that risk factors for disruptive behaviors include catechol-O-methyltransferase (COMT) Val158Met (rs4680) polymorphism and environmental influences. An unanswered question is whether there is a change in these risk factors over stages of youth development. This longitudinal study examines the interaction effect of Val158Met and stressful life events (SLE) on youth externalizing behaviors from ages 9-11. Participants were 2363 children of European ancestry recruited as part of the Adolescent Brain Cognitive Development study. Repeated measures linear mixed models were used to examine the effect of the interaction between Val158Met and SLE (G × E) on disruptive behaviors over development. Externalizing behaviors were analyzed at both baseline and two-year follow-up. Both Val158Met genotype and SLE scores demonstrated significant main effects on disruptive behaviors in youth, and those effects were consistent at both time points. G × E was not associated with externalizing behaviors. Youth who carried the Val allele and/or were exposed to higher SLE consistently had increased externalizing behavior scores. To our knowledge, this is the first study to longitudinally examine the interaction effects of Val158Met and SLE on externalizing behaviors in youth. The results highlight the importance of understanding the genetic and environmental factors underlying externalizing behaviors for better detection of at-risk youth, helping further with early prevention efforts. The findings propose that COMT Val158Met genotype may act as a biomarker for development of novel treatment strategies for disruptive behaviors.
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Affiliation(s)
- Tuana Kant
- Institute of Medical Science, University of Toronto, Toronto, M5S 1A8, Canada
- Temerty Faculty of Medicine, University of Toronto, Toronto, M5S 1A8, Canada
- Brain Science Department, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, M6J 1H4, Canada
| | - Emiko Koyama
- Brain Science Department, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, M6J 1H4, Canada
- Laboratory for Molecular Pathology of Psychiatric Disorders, RIKEN Center for Brain Science, Saitama, 351-0198, Japan
- Margaret and Wallace McCain Centre for Child, Youth and Family Mental Health, Centre for Addiction and Mental Health, Toronto, M6J 1H4, Canada
| | - Clement C. Zai
- Institute of Medical Science, University of Toronto, Toronto, M5S 1A8, Canada
- Temerty Faculty of Medicine, University of Toronto, Toronto, M5S 1A8, Canada
- Department of Psychiatry, University of Toronto, Toronto, M5S 1A8, Canada
- Laboratory Medicine and Pathobiology, University of Toronto, Toronto, M5S 1A8, Canada
| | - Marcos Sanches
- Krembil Centre for Neuroinformatics, Centre for Addiction and Mental Health, Toronto, M6J 1H4, Canada
| | - Joseph H. Beitchman
- Institute of Medical Science, University of Toronto, Toronto, M5S 1A8, Canada
- Margaret and Wallace McCain Centre for Child, Youth and Family Mental Health, Centre for Addiction and Mental Health, Toronto, M6J 1H4, Canada
- Department of Psychiatry, University of Toronto, Toronto, M5S 1A8, Canada
| | - James L. Kennedy
- Institute of Medical Science, University of Toronto, Toronto, M5S 1A8, Canada
- Brain Science Department, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, M6J 1H4, Canada
- Department of Psychiatry, University of Toronto, Toronto, M5S 1A8, Canada
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Kang J, Park M, Oh CM, Kim T. High-fat diet-induced dopaminergic dysregulation induces REM sleep fragmentation and ADHD-like behaviors. Psychiatry Res 2023; 327:115412. [PMID: 37607442 DOI: 10.1016/j.psychres.2023.115412] [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: 01/17/2023] [Revised: 07/27/2023] [Accepted: 08/10/2023] [Indexed: 08/24/2023]
Abstract
Consumption of a high-fat diet (HFD) has been associated with reduced wakefulness and various behavioral deficits, including anxiety, depression, and anhedonia. The dopaminergic system, which plays a crucial role in sleep and ADHD, is known to be vulnerable to chronic HFD. However, the association between HFD-induced behavioral and molecular changes remains unclear. Therefore, we investigated the effects of a HFD on the dopaminergic system and its association with behavioral deficits in male mice. The mice were divided into normal diet and HFD groups and were analyzed for sleep patterns, behavior tests, and transcription levels of dopamine-related genes in the brain. The HFD group showed decreased wakefulness, increased REM sleep with fragmented patterns, decreased time spent in the center zone of the open field test, shorter immobile time in the tail suspension test, impaired visuospatial memory, and reduced sucrose preference. Additionally, the HFD group had decreased mRNA levels of D1R, COMT, and DAT in the nucleus accumbens, which negatively correlated with REM sleep proportion and REM sleep bout count. The results suggest that HFD-induced behavioral deficits were resemblance to ADHD-like behavioral phenotypes and disturbs REM sleep by dysregulating the dopaminergic system.
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Affiliation(s)
- Jiseung Kang
- Department of Biomedical Science and Engineering, Gwangju Institute of Science and Technology, Gwangju 61005, Republic of Korea
| | - Mincheol Park
- Department of Biomedical Science and Engineering, Gwangju Institute of Science and Technology, Gwangju 61005, Republic of Korea
| | - Chang-Myung Oh
- Department of Biomedical Science and Engineering, Gwangju Institute of Science and Technology, Gwangju 61005, Republic of Korea.
| | - Tae Kim
- Department of Biomedical Science and Engineering, Gwangju Institute of Science and Technology, Gwangju 61005, Republic of Korea.
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姚 珂, 董 强, 叶 兰. [Recent research on the association between depressive disorder and gene polymorphisms in adolescents]. ZHONGGUO DANG DAI ER KE ZA ZHI = CHINESE JOURNAL OF CONTEMPORARY PEDIATRICS 2023; 25:328-332. [PMID: 36946171 PMCID: PMC10032068 DOI: 10.7499/j.issn.1008-8830.2208178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Accepted: 12/15/2022] [Indexed: 03/23/2023]
Abstract
Biogenetics plays an important role in the pathogenesis of depressive disorder in adolescents. Various genetic polymorphism studies have updated the understanding of adolescent depressive disorder. However, due to the influence of gene-environment interaction and age of puberty, the influence of gene polymorphisms on adolescent depressive disorder is complicated to clarify. Investigating and clarifying the relationship between gene polymorphisms and adolescent depressive disorder will promote the research on the pathogenesis of this disorder and provide a reference for the prevention and treatment of this disorder. This article reviews the genetic polymorphisms related to adolescent depressive disorder.
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Kanarik M, Grimm O, Mota NR, Reif A, Harro J. ADHD co-morbidities: A review of implication of gene × environment effects with dopamine-related genes. Neurosci Biobehav Rev 2022; 139:104757. [PMID: 35777579 DOI: 10.1016/j.neubiorev.2022.104757] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 06/25/2022] [Accepted: 06/26/2022] [Indexed: 02/07/2023]
Abstract
ADHD is a major burden in adulthood, where co-morbid conditions such as depression, substance use disorder and obesity often dominate the clinical picture. ADHD has substantial shared heritability with other mental disorders, contributing to comorbidity. However, environmental risk factors exist but their interaction with genetic makeup, especially in relation to comorbid disorders, remains elusive. This review for the first time summarizes present knowledge on gene x environment (GxE) interactions regarding the dopamine system. Hitherto, mainly candidate (GxE) studies were performed, focusing on the genes DRD4, DAT1 and MAOA. Some evidence suggest that the variable number tandem repeats in DRD4 and MAOA may mediate GxE interactions in ADHD generally, and comorbid conditions specifically. Nevertheless, even for these genes, common variants are bound to suggest risk only in the context of gender and specific environments. For other polymorphisms, evidence is contradictory and less convincing. Particularly lacking are longitudinal studies testing the interaction of well-defined environmental with polygenic risk scores reflecting the dopamine system in its entirety.
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Affiliation(s)
- Margus Kanarik
- Chair of Neuropsychopharmacology, Institute of Chemistry, University of Tartu, Ravila 14A Chemicum, 50411 Tartu, Estonia
| | - Oliver Grimm
- Department of Psychiatry, Psychosomatic Medicine and Psychotherapy, University Hospital, Goethe University, Frankfurt, Germany
| | - Nina Roth Mota
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, the Netherlands; Department of Psychiatry, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Andreas Reif
- Department of Psychiatry, Psychosomatic Medicine and Psychotherapy, University Hospital, Goethe University, Frankfurt, Germany
| | - Jaanus Harro
- Chair of Neuropsychopharmacology, Institute of Chemistry, University of Tartu, Ravila 14A Chemicum, 50411 Tartu, Estonia; Psychiatry Clinic, North Estonia Medical Centre, Paldiski Road 52, 10614 Tallinn, Estonia.
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COMT Val/Met and Psychopathic Traits in Children and Adolescents: A Systematic Review and New Evidence of a Developmental Trajectory toward Psychopathy. Int J Mol Sci 2022; 23:ijms23031782. [PMID: 35163702 PMCID: PMC8836546 DOI: 10.3390/ijms23031782] [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: 12/21/2021] [Revised: 01/29/2022] [Accepted: 01/31/2022] [Indexed: 12/10/2022] Open
Abstract
Psychopathic traits in youth may lead to adult criminal behaviors/psychopathy. The Val158Met polymorphism of catechol-O-methyltransferase (COMT) may influence the risk for psychopathy-related behaviors, while acting as a biomarker for predicting treatment response to dopaminergic medications. The literature shows inconsistent findings, making the interpretation of COMT's role difficult. The aims of this article are (i) to conduct a systematic review to analyze the effects of COMT Val158Met on psychopathic traits in children and adolescents, and (ii) to present new evidence on the developmental trajectory of the association of Val158Met and youth psychopathic traits. For the systematic review, a literature search was conducted using PubMed, EMBASE, OVID Medline and PsychINFO with the search terms for psychopathic traits, Val158Met and age of interest. In our genotype study, the COMT Val158Met genotype of 293 youth with European ancestry was analyzed in association with the psychopathy-related behavior scores from the Child Behavior Checklist and the Psychopathy Screening Device. To examine the potential influence of developmental changes, the sample was split into at or above and below age 13, and analyses were performed in males and females separately. The literature search yielded twenty-eight articles to be included in the systematic review, which demonstrated mixed results on the association depending on environmental factors, sex ratios, age groups and behavioral disorder diagnoses. The results from our genotype study revealed that Met homozygous youth in the below age 13 group and conversely Val carrier youth in the above age 13 group were more likely to display psychopathic traits. To our knowledge, this is the first study to systematically review the effects of COMT Val158Met on psychopathic traits in childhood and adolescence, and to provide new evidence on the changing effects of Val158Met on psychopathy-related behaviors with development. Elucidating the role of the COMT genotype in conjunction with the child versus adolescent stage of development for psychopathic traits may help predict treatment response, and may lead to early intervention and prevention strategies.
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Whittaker AC, Ginty A, Hughes BM, Steptoe A, Lovallo WR. Cardiovascular Stress Reactivity and Health: Recent Questions and Future Directions. Psychosom Med 2021; 83:756-766. [PMID: 34297004 DOI: 10.1097/psy.0000000000000973] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE High cardiovascular reactions to psychological stress are associated with the development of hypertension, systemic atherosclerosis, and cardiovascular disease. However, it has become apparent that low biological stress reactivity also may have serious consequences for health, although less is known about the mechanisms of this. The objectives of this narrative review and opinion article are to summarize and consider where we are now in terms of the usefulness of the reactivity hypothesis and reactivity research, given that both ends of the reactivity spectrum seem to be associated with poor health, and to address some of the key criticisms and future challenges for the research area. METHODS This review is authored by the members of a panel discussion held at the American Psychosomatic Society meeting in 2019, which included questions such as the following: How do we measure high and low reactivity? Can high reactivity ever indicate better health? Does low or blunted reactivity simply reflect less effort on task challenges? Where does low reactivity originate from, and what is a low reactor? RESULTS Cardiovascular (and cortisol) stress reactivity are used as a model to demonstrate an increased understanding of the different individual pathways from stress responses to health/disease and show the challenges of how to understand and best use the reconstruction of the long-standing reactivity hypothesis given recent data. CONCLUSIONS This discussion elucidates the gaps in knowledge and key research issues that still remain to be addressed in this field, and that systematic reviews and meta-analyses continue to be required.
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Affiliation(s)
- Anna C Whittaker
- From the Faculty of Health Sciences and Sport (Whittaker), University of Stirling, Stirling, Scotland, United Kingdom; Department of Psychology and Neuroscience (Ginty), Baylor University, Waco, Texas; School of Psychology (Hughes), National University of Ireland, Galway, Ireland; Institute of Epidemiology & Health (Steptoe), University College London, London, United Kingdom; and Department of Psychiatry and Behavioral Sciences (Lovallo), Norman, University of Oklahoma Health Sciences Center and VA Medical Center, Oklahoma
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Childhood disadvantage, neurocognitive development and neuropsychiatric disorders: Evidence of mechanisms. Curr Opin Psychiatry 2021; 34:306-323. [PMID: 33587493 PMCID: PMC9458466 DOI: 10.1097/yco.0000000000000701] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE OF REVIEW Children living in socioeconomically disadvantaged households have excess risks of neurodevelopmental and neuropsychiatric problems. The purpose of this review is to synthesize evidence for mechanisms that may contribute to these excess risks. RECENT FINDINGS The majority of the 60 studies included in our review focused on children's neurocognitive development and behavioural problems. About half conducted mediation analyses of factors in the family and neighbourhood environments, including access to resources (e.g. cognitive inputs within the home environment) and exposure to stressors (e.g. negative parenting practices), as well as neurobiological embedding of childhood disadvantage. In addition, many studies conducted moderation analyses of factors that were hypothesized to interact with (i.e. exacerbate or mitigate) the harmful effects of childhood disadvantage. SUMMARY Many of the factors that contribute to the excess risk of neurodevelopmental and neuropsychiatric problems among children in disadvantaged households are potentially modifiable (e.g. cognitively stimulating materials, parental language input, cultural resources, parental stress and psychopathology, negative parenting, neighbourhood violence). If their causality is ultimately established, they could be targets for the prevention and reduction of disparities. The continued search for mechanisms should not detract from work to reduce and hopefully eliminate children's exposure to disadvantage.
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al'Absi M, Ginty AT, Lovallo WR. Neurobiological mechanisms of early life adversity, blunted stress reactivity and risk for addiction. Neuropharmacology 2021; 188:108519. [PMID: 33711348 DOI: 10.1016/j.neuropharm.2021.108519] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 02/13/2021] [Accepted: 03/05/2021] [Indexed: 12/20/2022]
Abstract
Blunted stress reactivity resulting from early exposure to stress during childhood and adolescence may increase vulnerability to addiction. Early life adversity (ELA) affects brain structure and function and results in blunted stress axis reactivity. In this review, we focus on the underlying neurobiological mechanisms associated with a blunted response to stress, ELA, and risk for addictive disorders. ELA and blunted reactivity are accompanied by unstable mood regulation, impulsive behaviors, and reduced cognitive function. Neuroimaging studies reveal cortical and subcortical changes in persons exposed to ELA and those who have a genetic disposition for addiction. We propose a model in which blunted stress reactivity may be a marker of risk for addiction through an altered motivational and behavioral reactivity to stress that contribute to disinhibited behavioral reactivity and impulsivity leading in turn to increased vulnerability for substance use. Evidence supporting this hypothesis in the context of substance use initiation, maintenance, and risk for relapse is presented. The effects of ELA on persons at risk for addiction may lead to early experimentation with drugs of abuse. Early adoption of drug intake may alter neuroregulation in such vulnerable persons leading to a permanent dysregulation of motivational responses consistent with dependence. This article is part of the special issue on 'Vulnerabilities to Substance Abuse'.
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Affiliation(s)
- Mustafa al'Absi
- Family Medicine and Biobehavioral Health, University of Minnesota Medical School, Duluth, MN, USA.
| | - Annie T Ginty
- Department of Psychology and Neuroscience, Baylor University, Waco, TX, USA
| | - William R Lovallo
- University of Oklahoma Health Sciences Center and VA Medical Center, Oklahoma City, OK, USA
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