Effects of the MAOA gene and levels of exposure to violence on antisocial outcomes

Good parent-child relationship protects against alcohol use in maltreated adolescent females carrying the MAOA-uVNTR susceptibility allele

Introduction

Risk-allele carriers of a Monoamine oxidase A (MAOA) gene, short-allele (MAOA-S) in males and long-allele (MAOA-L) in females, in the presence of a negative environment, are associated with alcohol misuse. Whether MAOA-S/L alleles also present susceptibility to a positive environment to mitigate the risk of alcohol misuse is unknown. Thus, we assessed the association of the three-way interaction of MAOA, maltreatment, and positive parent-child relationship with alcohol consumption among adolescents.

Methods

This prospective study included 1416 adolescents (females: 59.88%) aged 16 - 19 years from Sweden, enrolled in the "Survey of Adolescent Life in Västmanland" in 2012. Adolescents self-reported alcohol consumption, maltreatment by a family (FM) or non-family member (NFM), parent-child relationship, and left saliva for MAOA genotyping.

Results and discussion

We observed sex-dependent results. Females carrying MAOA-L with FM or NFM and a good parent-child relationship reported lower alcohol consumption than those with an average or poor parent-child relationship. In males, the interactions were not significant. Results suggest MAOA-L in females, conventionally regarded as a "risk", is a "plasticity" allele as it is differentially susceptible to negative and positive environments. Results highlight the importance of a good parent-child relationship in mitigating the risk of alcohol misuse in maltreated individuals carrying genetic risk. However, the interactions were not significant after adjusting to several environmental and behavioural covariates, especially parent's alcohol use, negative parent-child relationship, and nicotine use (smoking and/or snus), suggesting predictor and outcome intersection. Future studies and frameworks for preventive strategies should consider these covariates together with alcohol consumption. More studies with larger sample sizes are needed to replicate the findings.

Sleep and violence perpetration: A review of biological and environmental substrates

Violence is a worldwide societal burden that negatively impacts individual health, wellbeing and economic development. Evidence suggests a bidirectional relationship between sleep changes and violence. This review details, evaluates and discusses the biological and demographic substrates linking sleep and violence perpetration, and summarizes the overlap of brain areas, functional neuronal systems and genetic features involved, not including violent behaviours during sleep. Knowledge on the biological variables that affect the individual's susceptibility to violent behaviour may have implications for criminology, management of detentions and rehabilitation strategies.

Exposición a violencia en el hogar y victimización por acoso escolar en adolescentes peruanos

Con el objetivo de evaluar la asociación entre la exposición a la violencia en el hogar y la victimización por acoso escolar en adolescentes peruanos de 12 a 17 años, durante el año 2019, se realizó un estudio transversal de análisis de datos secundario de la Encuesta Nacional sobre Relaciones Sociales (ENARES) de 2019. La variable independiente fue la exposición a violencia en el hogar y la variable dependiente fue la victimización por acoso escolar, que incluyó al acoso psicológico y físico. Además, se incluyeron posibles variables de confusión. Se utilizaron modelos de regresión logística multinomial y se estimaron razones de riesgo relativo (RRR) con sus intervalos del 95% de confianza (IC95%). En todos los cálculos se consideró el muestreo complejo de la ENARES 2019. Se incluyeron datos de 1.569 adolescentes peruanos. El 38,1% estuvo expuesto a violencia en el hogar, mientras que el 37,9% fue víctima solo de acoso psicológico, el 3,4% solo de acoso físico y el 22,4% de ambos tipos de acoso escolar. Los adolescentes, que siempre o casi siempre estuvieron expuestos a la violencia en el hogar, tuvieron 4,8 veces la probabilidad de ser víctimas de acoso escolar (RRR = 4,80; IC95%: 2,44-9,42), ajustado por múltiples variables de confusión. En Perú, los adolescentes peruanos de 12 a 17 años que estuvieron expuestos a violencia en el hogar tuvieron mayor probabilidad de ser víctimas de acoso escolar. Estos resultados deben llamar la atención de los decisores en políticas públicas de protección infantil.

High-dose testosterone treatment reduces monoamine oxidase A levels in the human brain: A preliminary report

The sex hormones testosterone and estradiol influence brain structure and function and are implicated in the pathogenesis, prevalence and disease course of major depression. Recent research employing gender-affirming hormone treatment (GHT) of gender dysphoric individuals and utilizing positron emission tomography (PET) indicates increased serotonin transporter binding upon high-dosages of testosterone treatment. Here, we investigated the effects of GHT on levels of monoamine oxidase A (MAO-A), another key target of antidepressant treatment. Participants underwent PET with the radioligand [¹¹C]harmine to assess cerebral MAO-A distribution volumes (V_T) before and four months after initiation of GHT. By the time this study was terminated for technical reasons, 18 transgender individuals undergoing GHT (11 transmen, TM and 7 transwomen, TW) and 17 cis-gender subjects had been assessed. Preliminary analysis of available data revealed statistically significant MAO-A V_T reductions in TM under testosterone treatment in six of twelve a priori defined regions of interest (middle frontal cortex (-10%), anterior cingulate cortex (-9%), medial cingulate cortex (-10.5%), insula (-8%), amygdala (-9%) and hippocampus (-8.5%, all p<0.05)). MAO-A V_T did not change in TW receiving estrogen treatment. Despite the limited sample size, pronounced MAO-A V_T reduction could be observed, pointing towards a potential effect of testosterone. Considering MAO-A's central role in regulation of serotonergic neurotransmission, changes to MAO-A V_T should be further investigated as a possible mechanism by which testosterone mediates risk for, symptomatology of, and treatment response in affective disorders.

Childhood Antisocial Behavior: A Neurodevelopmental Problem

Early-onset disruptive, aggressive, and antisocial behavior is persistent, can become increasingly serious as children grow older, and is difficult to change. In 2007, our group proposed a theoretical model highlighting the interplay between neurobiological deficits and cognitive and emotional functioning as mediators of the link between genetic influences and early social adversity, on the one hand, and antisocial behavioral problems in childhood, on the other. In this article, we review the post-2007 evidence relevant to this model. We discuss research on genetics/epigenetics, stress/arousal regulation, and emotion and executive functioning in support of the argument that antisocial children, especially those who persist in engaging in antisocial behavior as they grow older, have a range of neuropsychological characteristics that are important in explaining individual differences in the severity and persistence of antisocial behavior. Current clinical practice tends not to acknowledge these individual neuropsychological risks factors or to target them for intervention. We argue that aggressive and disruptive behavior in childhood should be regarded as a neurodevelopmental problem and that intervening at the level of mediating neuropsychological processes represents a promising way forward in tackling these serious behavioral problems. Expected final online publication date for the Annual Review of Psychology, Volume 73 is January 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Self-Reported Lifetime Violence Exposure and Self-Compassion Associated With Satisfaction of Life in Historically Black College and University Students

In the United States, approximately 25% of minors have witnessed a violent act, specifically physical assault. African Americans from under-served backgrounds are more likely than other racial and ethnic groups to be exposed to traumatic events. However, there is scant literature examining violence exposure, SC, and life satisfaction collectively, specifically in an African American college sample. The current study sought to determine the associations among violence exposure, SC components, and life satisfaction in an African American college sample. The current sample was comprised of 356 participants (80% female) with a mean age of 20.23 (SD = 1.70). Eighty-eight participants (25%) reported being exposed to violence in their lifetime. Employing logistic regression, we determined violence exposed individuals were less likely to report high satisfaction of life than their non-exposed counterparts (OR = 0.58, 95% CIs = 0.33, 1.00). Individuals with high level of self-kindness were approximately two times more likely to have higher satisfaction of life (OR = 2.48; CI = 1.52, 4.05) compared to their low level self-kindness counterparts and in the presence of demographic covariates. These findings may educate and increase awareness of the impacts of traumatic events. This education could lead to the implementation of interventions to build upon overall well-being in order increase life satisfaction in college students.

Monoamino Oxidase A Gene Single-Nucleotide Polymorphisms and Methylation Status and the Risk of Violent Suicide Attempts in Affective Disorder Patients

Background: When investigating the neurobiology of suicidal behavior, Monoamino Oxidase A (MAOA) is one of the prime suspects to consider. Interestingly, MAOA dysregulation has also been associated with violent behavior in previous publications. In the present study, we aimed to establish an association between polymorphisms of the MAOA gene and methylation status of the MAOA gene Exon I, and suicide attempts with violent methods in a sample of affective disorder patients. Methods: Eight hundred fourteen Caucasian affective disorder patients were assessed at the Department of Psychiatry and Psychotherapy of the Medical University Vienna, the Karl Landsteiner University for Health and Science and Zentren für seelische Gesundheit, BBRZ-Med Leopoldau. An assemblage of psychiatric interviews was performed (e.g., SCAN, HAMD, SBQ-R, CTQ) and DNA samples of peripheral blood cells were collected for Sequenom MassARRAY® iPLEX Gold genotyping and Multiplexed and Sensitive DNA Methylation Testing. Results: Female affective disorder patients with a history of violent suicide attempt were found to have a significantly increased frequency of the AA genotype in the rs5906957 single nucleotide polymorphism (p = 0.003). Furthermore, the MAOA gene exon I promoter region showed significantly decreased methylation in female violent suicide attempter(s) as opposed to female affective disorder patients who had no history of suicide attempt or no history of suicide attempt with violent method. Limitations: The small sample size hampers to reveal small genetic effects as to be expected in psychiatric disorders. Conclusions: This study offers promising findings about associations between the MAOA gene and violent suicide especially in women.

Gene-Environment Interactions in Major Mental Disorders in the Czech Republic

BACKGROUND

Mental disorders affect about one-third of the human population, are typically chronic and significantly decrease the quality of life. Presently, the treatment of mental illnesses is far from adequate with a substantial proportion of the patients being pharmacoresistant and suffering from relapses. One of the reasons for this complicated situation is that we do not precisely know about the causes of mental disorders, so their treatment cannot be causal. The etiology of a mental disorder is typically based on a combination of molecular (genetic) and environmental factors.

AIM

The aim of the project is to discover the gene-environment interactions (GxE) in a wide spectrum of mental disorders.

METHODS

The design of our study is innovative in the sense that we intend to study large groups of associated mental disorders as a whole instead of in isolation. This would enable us to map out the possible environmental causal factors in detail in relation to their character, magnitude and timing. The project also allows a study of genetics (including epigenetics and microbiomes) as well as the environment simultaneously. We plan on involving three study groups: the first group are patients suffering from schizophrenia or a mood disorder such as major depression, recurrent depressive disorder and bipolar affective disorder; the second group of patients have anxiety disorders; and the third group are healthy volunteers from the general population who are genetically unrelated. All of the study subjects will undergo the following assessments: a psychiatric examination, the identification of stressful life events with the aid of a questionnaire, the examination of their reaction to stress, genetic and epigenetic (microRNA) assessments and the analysis of oral and gut microbiome.

CONCLUSION

We expect that some of the genetic as well as environmental factors in the studied mental disorders are shared, while some others are specific. We also expect that the GxE (gene-environment interaction) in schizophrenic and affective disorders will be different from the GxE in anxiety disorders and that the GxE in the studied mental disorders will differ generally from the GxE in healthy volunteers. Our results can help in the prevention and individualized treatment of a range of mental disorders.

State-of-the-Science Review of Non-Chemical Stressors Found in a Child's Social Environment

Background: Children are exposed to chemical and non-chemical stressors from their built, natural, and social environments. Research is needed to advance our scientific understanding of non-chemical stressors, evaluate how they alter the biological response to a chemical stressor, and determine how they impact children’s health and well-being. To do this, we conducted a state-of-the-science review of non-chemical stressors found in a child’s social environment. Methods: Studies eligible for inclusion in this review were identified through a search of the peer-reviewed literature using PubMed and PsycINFO. Combinations of words associated with non-chemical stressors and children were used to form search strings. Filters were used to limit the search to studies published in peer-reviewed journals from 2000–2016 and written in English. Publications found using the search strings and filters went through two rounds of screening. Results: A total of 146 studies met the inclusion criteria. From these studies, 245 non-chemical stressors were evaluated. The non-chemical stressors were then organized into 13 general topic areas: acculturation, adverse childhood experiences, economic, education, family dynamics, food, greenspace, neighborhood, social, stress, urbanicity, violence, and other. Additional information on health outcomes, studies evaluating both chemical and non-chemical stressors, and animal studies are provided. This review provides evidence that non-chemical stressors found in a child’s social environment do influence their health and well-being in both beneficial (e.g., salutatory effects of greenspace and social support) and adverse (e.g., poor relationships between health and selected non-chemical stressors such as economics, educational attainment, exposure to violence, stress) ways. Conclusions: This literature review identified a paucity of studies addressing the combined effects of chemical and non-chemical stressors and children’s health and well-being. This literature review was further complicated by inconsistencies in terminology, methodologies, and the value of non-chemical stressor research in different scientific disciplines. Despite these limitations, this review showed the importance of considering non-chemical stressors from a child’s social environment when addressing children’s environmental health considerations.

Psychometric Properties and Development of a Scale Designed to Evaluate the Potential of Predatory Violent Behavior

The objective of this study was to develop and determine the psychometric properties of an instrument designed to detect traits and behavior that are associated with predatory violent behavior, which is defined as a determined, planned, controlled, and proactive aggression. The sample was comprised of 564 students, mostly in their last year of high school, or in their first year of college. The initial instrument had 78 items, ultimately resulting in 13 with good internal consistency (α = 0.825). Factor analysis showed four factors: anger-in, appeal for weapons, suicidal ideation, and the tendency to take justice into one’s own hands. Said factors showed significant correlations of convergent validity. Data shown here allows inferring that the instrument is a novel and concise tool that evaluates and detects the potential of predatory violent behavior.

Cumulative risk and protection effect of serotonergic genes on male antisocial behaviour: results from a prospective cohort assessed in adolescence and early adulthood

BACKGROUND

Heritability of antisocial behaviour is estimated at approximately 50% and involves multiple genes.AimsTo investigate the cumulative genetic effects of 116 single nucleotide polymorphisms mapping to 11 candidate serotonergic genes and antisocial behaviours, in adolescence and in early adulthood.

METHOD

Participants were 410 male members of the Quebec Longitudinal Study of Kindergarten Children, a population-based cohort followed up prospectively from age 6 to age 23. The serotonergic genes were selected based on known physiological processes and prior associations with antisocial behaviours. Antisocial behaviours were self-reported and assessed by using semi-structured interviews in adolescence and in adulthood.

RESULTS

Cumulative, haplotype-based contributions of serotonergic genes conferring risk and protection for antisocial behaviours were detected by using multilocus genetic profile risk scores (MGPRSs) and multilocus genetic profile protection scores (MGPPSs). Cumulatively, haplotype-based MGPRSs and MGPPSs contributed to 9.6, 8.5 and 15.2% of the variance in general delinquency in adolescence, property/violent crimes in early adulthood and physical partner violence in early adulthood, respectively.

CONCLUSIONS

This study extends previous research by showing a cumulative effect of multiple haplotypes conferring risk and protection to antisocial behaviours in adolescence and early adulthood. The findings further support the relevance of concomitantly considering multiple serotonergic polymorphisms to better understand the genetic aetiology of antisocial behaviours. Future studies should investigate the interplay between risk and protective haplotype-based multilocus genetic profile scores with the environment.

DECLARATION OF INTEREST

I.O.-M. holds a Canada Research Chair in the developmental origins of vulnerability and resilience.

Is childhood maltreatment associated with murderous ideation and behaviors in adolescents in China?

Previous research has revealed associations between childhood maltreatment (CM) and adverse health behaviors. However, little is known about the relationship between CM and adolescent murderous ideation and behaviors. A total of 5726 middle and high school students completed the Childhood Trauma Questionnaire-Short Form and the Murderous Ideation and Behaviors Questionnaire. The findings revealed that the prevalence rates for murderous ideation, plans, preparation, and attempts were 9.9%, 2.8%, 1.3%, and 0.6%, respectively. The results of multinomial logistic regression models indicated that adolescents who experienced CM were more likely to exhibit murderous ideation and behaviors, with adjusted odds ratios (AORs) ranging from 2.55 to 22.31. Additionally, a significant dose-response relationship was found between the number of CM types experienced and murderous ideation and behaviors (AORs ranging from 1.52 to 2.45). The odds of participants who had experienced three or five types of CM were significantly associated with murderous ideation and behaviors, with AORs ranging from 4.55 to 28.30 and from 5.26 to 85.45, respectively. The findings highlighted that adolescents who engaged in murderous ideation and behaviors were more likely to have a personal history of CM and revealed a dose-response relationship between the number of CM types and murderous ideation and behaviors.

ADHD, CD, and ODD: Systematic review of genetic and environmental risk factors

This review aims to analyze the relationships between Attention-Deficit Hyperactivity Disorder (ADHD), Oppositional Defiant Disorder (ODD), and Conduct Disorder (CD), particularly regarding the relative importance of genetic and environmental factors in the development of these disorders. Studies that examined at least two of these disorders were obtained from multiple databases, following the procedures of the Cochrane Collaboration initiative. Of the 279 documents obtained, nine were retained for in-depth analysis and were considered eligible for inclusion. In addition, eight studies from the manual search were included. The objectives, methodological aspects (sample and instruments), and the main conclusions were extracted from each study. Overall, the results suggest that (a) the causes for the onset and maintenance of these disorders are more associated with genetic factors than environmental factors, although the importance of the latter is recognized, and (b) children with ADHD have a predisposition to manifest behaviors that are common to ODD and CD, including the antisocial behavior that these children often display.

Associations of serotonin transporter gene promoter polymorphisms and monoamine oxidase A gene polymorphisms with oppositional defiant disorder in a Chinese Han population

BACKGROUND

Oppositional defiant disorder (ODD) is a behavioral disorder that mainly refers to a recurrent pattern of disobedient, defiant, negativistic and hostile behaviors toward authority figures. Previous studies have showed associations of serotonin transporter (5-HTT) and monoamine oxidase A (MAOA) with behavioral and psychiatric disorders. The purposes of this study were to investigate the potential association of 5-HTT gene promoter polymorphism (5-HTTLPR) and MAOA gene polymorphism with susceptibility to ODD in a Han Chinese school population.

METHODS

The 5-HTTLPR gene polymorphism and the MAOA gene polymorphism were genotyped in a case-control study of 257 Han Chinese children (123 ODD and 134 healthy controls).

RESULTS

There was significant difference in the allele distribution of 5-HTTLPR (χ² = 7.849, P = 0.005) between the ODD and control groups. Further, there were significant differences in genotype (χ² = 5.168, P = 0.023) and allele distributions (χ² = 10.336, P = 0.001) of the MAOA gene polymorphism that is variable-number tandem repeat (MAOA-uVNTR) between two groups. Moreover, there were significant differences in genotype (χ² = 4.624, P = 0.032) and allele distributions (χ² = 9.248, P = 0.002) of MAOA-uVNTR only in the male ODD and healthy groups.

CONCLUSIONS

Our results suggest that 5-HTTLPR and MAOA-uVNTR gene variants may contribute to susceptibility to ODD. Further, MAOA-uVNTR gene polymorphism may play a role in susceptibility to ODD only in male children.

Associations Between MAOA-uVNTR Genotype, Maltreatment, MAOA Methylation, and Alcohol Consumption in Young Adult Males

BACKGROUND

Epigenetic mechanisms are candidate moderators of the effect of maltreatment on brain and behavior. Interactions between maltreatment and the monoamine oxidase A upstream variable number tandem repeat genotype (MAOA-uVNTR) are associated with alcohol-related problems. However, presently it is not known whether DNA methylation moderates this association. The study focused on 53 young adult males and aimed to determine whether MAOA methylation moderated the association of alcohol-related problems with the interaction of MAOA-uVNTR and maltreatment, and whether alcohol consumption moderated the association of MAOA methylation with the interaction of MAOA-uVNTR and maltreatment.

METHODS

MAOA-uVNTR genotypes with ≤ 3 and > 3 repeats were categorized as short (S) and long (L), respectively. Data on maltreatment were obtained retrospectively, using self-reported questionnaires. DNA methylation of 16 candidate CpGs within part of the MAOA first exon and intron was assessed and grouped based on principal component analyses. Alcohol-related problems were assessed using the Alcohol Use Disorders Identification Test (AUDIT). Alcohol consumption was measured using AUDIT-C. Moderation effects were assessed and probed using the moderated moderation model and Johnson-Neyman's method, respectively.

RESULTS

Carriers of the S allele, who experienced maltreatment and displayed lower Component 1 (mean of CpGs 13-16 in the first intron) MAOA methylation levels, reported higher AUDIT score in contrast to L-allele carriers. Carriers of the S allele, who reported higher AUDIT-C score and experienced maltreatment, displayed lower Component 3 (mean of CpGs 2-6 in the first exon) MAOA methylation levels than L-allele carriers.

CONCLUSIONS

Intronic methylation moderated the association of alcohol-related problems with the interaction of MAOA-uVNTR and maltreatment. Alcohol consumption moderated the association of exonic methylation with the interaction of MAOA-uVNTR and maltreatment. These results suggest that epigenetic factors as well as genotype and maltreatment play a role in the development of alcohol misuse among young adult males.

Loss of chromosome Y in blood, but not in brain, of suicide completers

Men have a higher rate of completed suicide than women, which suggests that sex chromosome abnormalities may be related to the pathophysiology of suicide. Recent studies have found an aberrant loss of chromosome Y (LOY) in various diseases; however, no study has investigated whether there is an association between LOY and suicide. The purpose of this study was to determine whether LOY occurs in men who completed suicide. Our study consisted of 286 male Japanese subjects comprised of 140 suicide completers without severe physical illness (130 post-mortem samples of peripheral blood and 10 brains) and 146 age-matched control subjects (130 peripheral blood samples from healthy individuals and 16 post-mortem brains). LOY was measured as the chromosome Y/chromosome X ratio of the fluorescent signal of co-amplified short sequences from the Y-X homologous amelogenin genes (AMELY and AMELX). Regression analyses showed that LOY in the blood of suicide completers was significantly more frequent than that found in controls (odds ratio = 3.50, 95% confidence interval = 1.21–10.10), but not in the dorsolateral prefrontal cortex (DLPFC) region of brain. Normal age-dependent LOY in blood was found in healthy controls (r = -0.353, p < 0.001), which was not seen in suicide completers (r = -0.119, p = 0.177). DLPFC tissue had age-dependent LOY (B = -0.002, p = 0.015), which was independent of phenotype. To our knowledge, this is the first study demonstrating that LOY in blood is associated with suicide completion. In addition, our findings are the first to also indicate that age-dependent LOY may occur not only in blood, but also in specific brain regions.

Monoamine Oxidase A (MAOA) Gene and Personality Traits from Late Adolescence through Early Adulthood: A Latent Variable Investigation

Very few molecular genetic studies of personality traits have used longitudinal phenotypic data, therefore molecular basis for developmental change and stability of personality remains to be explored. We examined the role of the monoamine oxidase A gene (MAOA) on extraversion and neuroticism from adolescence to adulthood, using modern latent variable methods. A sample of 1,160 male and 1,180 female participants with complete genotyping data was drawn from a British national birth cohort, the MRC National Survey of Health and Development (NSHD). The predictor variable was based on a latent variable representing genetic variations of the MAOA gene measured by three SNPs (rs3788862, rs5906957, and rs979606). Latent phenotype variables were constructed using psychometric methods to represent cross-sectional and longitudinal phenotypes of extraversion and neuroticism measured at ages 16 and 26. In males, the MAOA genetic latent variable (AAG) was associated with lower extraversion score at age 16 (β = −0.167; CI: −0.289, −0.045; p = 0.007, FDRp = 0.042), as well as greater increase in extraversion score from 16 to 26 years (β = 0.197; CI: 0.067, 0.328; p = 0.003, FDRp = 0.036). No genetic association was found for neuroticism after adjustment for multiple testing. Although, we did not find statistically significant associations after multiple testing correction in females, this result needs to be interpreted with caution due to issues related to x-inactivation in females. The latent variable method is an effective way of modeling phenotype- and genetic-based variances and may therefore improve the methodology of molecular genetic studies of complex psychological traits.

Developmental Origins of Chronic Physical Aggression: A Bio-Psycho-Social Model for the Next Generation of Preventive Interventions

This review describes a bio-psycho-social approach to understanding and preventing the development of chronic physical aggression. The debate on the developmental origins of aggression has historically opposed genetic and environmental mechanisms. Recent studies have shown that the frequency of physical aggression peaks in early childhood and then decreases until old age. Molecular genetic studies and twin studies have confirmed important genetic influences. However, recent epigenetic studies have highlighted the important role of environments in gene expression and brain development. These studies suggest that interrelated bio-psycho-social channels involved in the development of chronic physical aggression are generally the product of an intergenerational transmission process occurring through assortative mating, genetic inheritance, and the inheritance of physical and social environmental conditions that handicap brain functioning and support the use of physical aggression to solve problems. Given these intergenerational mechanisms and physical aggression onset in infancy, it appears clear that preventive interventions should start early in pregnancy, at the latest.

Associations among oxytocin receptor gene (OXTR) DNA methylation in adulthood, exposure to early life adversity, and childhood trajectories of anxiousness

Recent models propose deoxyribonucleic acid methylation of key neuro-regulatory genes as a molecular mechanism underlying the increased risk of mental disorder associated with early life adversity (ELA). The goal of this study was to examine the association of ELA with oxytocin receptor gene (OXTR) methylation among young adults. Drawing from a 21-year longitudinal cohort, we compared adulthood OXTR methylation frequency of 46 adults (23 males and 23 females) selected for high or low ELA exposure based on childhood socioeconomic status and exposure to physical and sexual abuse during childhood and adolescence. Associations between OXTR methylation and teacher-rated childhood trajectories of anxiousness were also assessed. ELA exposure was associated with one significant CpG site in the first intron among females, but not among males. Similarly, childhood trajectories of anxiousness were related to one significant CpG site within the promoter region among females, but not among males. This study suggests that females might be more sensitive to the impact of ELA on OXTR methylation than males.

Monoamine Oxidase A in Antisocial Personality Disorder and Borderline Personality Disorder

Purpose of Review

Variation in the monoamine oxidase A (MAO-A) gene and MAO-A enzyme levels have been linked to antisocial behavior and aggression in clinical and non-clinical populations. Here, we provide an overview of the genetic, epigenetic, and neuroimaging research that has examined MAO-A structure and function in antisocial personality disorder (ASPD) and borderline personality disorder (BPD).

Recent Findings

The low-activity MAO-A variable nucleotide tandem repeat genetic polymorphism has shown a robust association with large samples of violent and seriously violent offenders, many of whom had ASPD. A recent positron emission tomography (PET) study of ASPD similarly revealed low MAO-A density in brain regions thought to contribute to the psychopathology of the condition. By contrast, PET has also demonstrated that brain MAO-A levels are increased in BPD and that they relate to symptoms of low mood and suicidality.

Summary

Candidate gene studies have produced the most compelling evidence connecting MAO-A genetic variants to both ASPD and BPD. Still, conflicting results abound in the literature, making it highly unlikely that ASPD or BPD is related to a specific MAO-A genetic variant. Future research should strive to examine how MAO-A genotypes interact with broad-spectrum environmental influences to produce brain endophenotypes that may ultimately become tractable targets for novel treatment strategies.

The role of MAO in personality and drug use

Monoamine oxidases, both MAO-A and MAO-B, have been implicated in personality traits and complex behaviour, including drug use. Findings supporting the involvement of MAO-A and MAO-B in shaping personality and in the development of strategies of making behavioural choices come from a variety of studies that have examined either prevalence of gene variants in clinical groups or population-derived samples, estimates of enzyme activity in blood or, by positron emission tomography, in the brain and, most recently, measurement of methylation of the gene. Most of the studies converge in associating MAO-A and MAO-B with impulsive, aggressive or antisocial personality traits or behaviours, including alcohol-related problems, and for MAO-A available evidence strongly supports interaction with adverse environmental exposures in childhood. What is known about genotype effects, and on expression and activity of the enzyme in the brain and in blood has not yet been possible to unite into a mechanistic model of the role of monoamine systems, but the reason for this low degree of generalization is likely caused by the cross-sectional nature of investigation that has not incorporated the developmental effects of MAO-s in critical time windows, including the foetal period. The "risk variants" of both MAO-s appear to increase behavioural plasticity, as supportive environments may particularly well enhance the hidden potential of their carriers. Importantly, male and female brain and behaviours have been found very different with regard to MAO×life events interaction. Future studies need to take into consideration these developmental aspects and sex/gender, as well as to specify the role of different types of environmental factors.

Commentary: Finding out the best way to tailor psychological interventions for children and families--a commentary on Ng and Weisz (2016)

The article by Ng and Weisz () on how to build a science of personalized intervention for youth mental health is ambitious and wide-ranging, being packed with penetrating analyses and imaginative proposals that set the agenda for psychotherapeutic research for years to come. It is driven by the desire to make therapy more effective, and underpinned by the notion that if therapy can be fitted more closely to individual characteristics, results will be better.