Deviant peer affiliation and antisocial behavior: interaction with Monoamine Oxidase A (MAOA) genotype

Sensitivity, but to which environment? Individual differences in sensitivity to parents and peers show domain-specific patterns and a negative genetic correlation

The idea that individuals differ in their sensitivity to the environment's effects is a cornerstone of developmental science. It has been demonstrated repeatedly, for different kinds of stressors, outcomes, and sensitivity markers. However, almost no empirical work was done to examine whether environmental sensitivity is domain-general (i.e., the same individuals are sensitive to different environmental contexts) or domain-specific (i.e., different individuals are sensitive to different environmental contexts), despite its importance to understanding human development, learning, and behavior. To address this question, phenotypic sensitivity to parents and to peers were compared in 1313 11-year-old Israeli adolescent twins. We found that, (1) our phenotypic markers indeed moderate environmental influences, with a discriminant predictive utility, (2) adolescents who are sensitive to their parents are not necessarily sensitive to their peers, and (3) sensitivity to parents and sensitivity to peers have different etiologies and show a negative genetic correlation, indicating that adolescents carrying genetic markers for sensitivity to parents are less likely to carry genetic markers for sensitivity to peers. These findings suggest that environmental sensitivity shows domain-specific patterns, as different individuals can be sensitive to different environments. We discuss the theoretical, empirical, and practical implications of domain-specificity of environmental sensitivity.

E-cigarette use among young adults: A latent class analysis examining co-use and correlates of nicotine vaping

INTRODUCTION

Although a significant proportion of young adults report e-cigarette use (nicotine vaping), little is known about co-use with other substances, including correlates that predict co-use. The current study aimed to identify co-occurring substance use patterns and evaluate multiple correlates in a college student sample.

METHODS

435 participants (21.4 ± 2.9 years; 57% women; 41% Hispanic/Latina/o, 29% Asian-American/Pacific Islander, 17% Caucasian/White, 6% Multiracial, and 5% African-American/Black) from a large, urban university were recruited in-person and completed an online survey in the fall of 2018 and the spring of 2019.

RESULTS

Using latent class analysis (LCA), four substance use patterns were identified: Binge Drinkers (7%); e-cigarette Users (8%); Cannabis Users (14%); and Low Substance Users (71%). The e-cigarette Users class was characterized by moderate or greater use (>5 days of nicotine vaping in past 30-days) as well as past 30-day binge drinking and cannabis use. Higher levels of deviant peer affiliation (aOR = 1.28[1.11-1.47], p < .01), impulsivity-lack of premeditation (aOR = 1.36[1.05-1.78], p < .05), and lower levels of social anxiety (aOR = 0.94[0.88-0.99], p < .05), predicted membership in the e-cigarette Users class.

CONCLUSIONS

The most pervasive co-occurring substance use was observed among the e-cigarette Users class. Young adults reporting moderate or greater levels of nicotine vaping tended to engage in binge drinking and cannabis use, which may ultimately increase risk of deleterious health outcomes. Deviant peer affiliation and impulsivity-lack of premeditation (but not internalizing symptoms) predicted membership in the e-cigarette Users class; consequently, public health efforts may benefit from increased selectivity in targeting young adults for e-cigarette prevention and intervention services.

Association of MAOA genetic variants and resilience with psychosocial stress: A longitudinal study of Syrian refugees

Early childhood trauma can have profound and lifelong effects on adult mental health and psychosocial wellbeing. Nevertheless, responses to trauma are highly variable. Genetic variants may help explain variation in responses to trauma by identifying alleles that associate with changes in mental health measures. Protective factors, such as resilience, likely also play an important role in responses to trauma. The effects of genetic variants, in combination with protective factors, on psychosocial health are not well understood, particularly in non-Western contexts. In this study, we test the relative influence of genetic variants of monoamine oxidase A (MAOA, a gene proposed to influence the impact of childhood trauma on adult violence and antisocial behavior), levels of resilience, and exposure to traumatic events on psychosocial stress and mental health trajectories over time. We use data from a cohort of 12-18-year-old Syrian refugees who were forcibly displaced to neighboring Jordan (n = 399). DNA samples and survey data on trauma exposure, resilience (CYRM-12), and psychosocial stress were collected at three time points: baseline, ~13 weeks, and ~48 weeks. Using multilevel models, we identified an association of MAOA variant, in males only, with symptom scores of psychosocial stress on the Perceived Stress Scale (PSS) over time (p = 8.1 x 10⁻⁴). We also found that resilience is strongly associated with PSS (p = 7.9 x 10⁻⁹), underscoring the importance of protective factors in influencing levels of psychosocial stress. Furthermore, there was an additive effect wherein the sharpest reductions in perceived psychosocial stress are seen in low-activity MAOA males with low trauma exposure or high resilience levels. Our results highlight the value of studies that integrate genetic and psychosocial factors to better understand complex phenotypes, such as responses to trauma in contexts of high trauma exposure.

The influence of parents and schools on developmental trajectories of antisocial behaviors in Caucasian and African American youths

African American youths are overrepresented in the American juvenile justice system relative to Caucasians. Yet, research on antisocial behaviors (ASB) has focused on predominantly Caucasian populations. Furthermore, relatively little is known about how environmental factors, such as supportive parenting (e.g., how close adolescents feel to their parent) and school connectedness (e.g., how supported adolescents feel at school), affect trajectories of ASB in Caucasians versus African Americans. This study mapped developmental trajectories of ASB in Caucasians (n = 10,764) and African Americans (n = 4,091) separately, using four waves of data from the National Longitudinal Study of Adolescent to Adult Health. We then examined supportive parenting and school connectedness on the trajectories of ASB. Four trajectories of ASB were identified for both Caucasians and African Americans: negligible, adolescence-peaked, low-persistence, and high-persistence ASB, although prevalence rates differed by racial-ethnic status. Supportive parenting reduced the risk of membership into the adolescence-peaked trajectory for both Caucasians and African Americans. However, school connectedness was less protective for African Americans than for Caucasians because it only predicted a lower risk of adolescence-peaked membership for African Americans. Findings may reflect the complex social dynamics between race and schools in the development of ASB.

The relationship between the MAOA-uVNTR polymorphism, delinquent peer affiliation, and antisocial behavior with a consideration of sex differences

With the advent of new and more readily usable gene sequencing techniques, researchers have been able to examine the interactions between genes and the environment (G X E) within a multitude of scientific perspectives. One area that G X E interactions have been implicated in is the development of antisocial behavior (ASB). Antisocial behavior consists of a wide range of maladaptive behaviors and has been at the forefront of public health and mental health concerns for decades. One genetic polymorphism that has been associated with ASB is MAOA-uVNTR. Meta-analytic studies have found the low-activity MAOA-uVNTR polymorphism to be associated with ASB from early childhood through adulthood. Recently, studies have begun to examine the independent and interactive G X E relationship between MAOA-uVNTR and deviant peer affiliation on ASB. Inconsistent with the broader literature, these findings suggest an interaction between high-activity MAOA-uVNTR and deviant peer affiliation on ASB in a mixed sex sample. The current study re-examines the relationship between MAOA-uVNTR, peer delinquency, and ASB with a consideration of sex differences in 291 college participants. Findings indicate an interaction between the low-activity allele of the MAOA-uVNTR and peer delinquency in predicting ASB. Results are also specific to differences between the sexes. Implications and future research are discussed.

Predicting Violent Behavior: What Can Neuroscience Add?

The ability to accurately predict violence and other forms of serious antisocial behavior would provide important societal benefits, and there is substantial enthusiasm for the potential predictive accuracy of neuroimaging techniques. Here, we review the current status of violence prediction using actuarial and clinical methods, and assess the current state of neuroprediction. We then outline several questions that need to be addressed by future studies of neuroprediction if neuroimaging and other neuroscientific markers are to be successfully translated into public policy.

Mediating effect of deviant peers on the relationship between sensation seeking and lifetime smoking among high school students

BACKGROUND

Despite the greater risk of lifetime smoking among high sensation seekers, it is difficult to change a sensation seeking tendency through interventions. Therefore, it is important to identify a modifiable factor mediating the link between these two conditions in order to weaken or disconnect the association.

OBJECTIVES

Based on the literature, deviant peers may play a pivotal role in explaining this association. Thus, we aimed to investigate the mediating effect of deviant peers on the association between sensation seeking and lifetime smoking among Korean adolescents.

METHODS

We analyzed secondary data obtained from 876 high school students. Approximately 51% of the participants were male. In order to investigate the mediating effect of deviant peers after controlling for 16 factors, we tested an indirect effect in a simple mediation model using the PROCESS macro, which is a regression-based approach.

RESULTS

We found a significant total effect of sensation seeking on lifetime smoking: greater risk of lifetime smoking among high sensation seekers. In addition, we found a significant mediating effect of deviant peers on the association between the two conditions. Specifically, higher sensation seeking successfully predicted a greater number of deviant peers, which, in turn, successfully predicted greater risk of lifetime smoking.

CONCLUSION

Given difficulties in directly changing levels of sensation seeking and the significant mediating effect of deviant peers on the association between the two conditions, prevention strategies focusing on peers may be advantageous for high sensation seekers in reducing their risk of lifetime smoking in adolescence.

Assessing the interplay between multigenic and environmental influences on adolescent to adult pathways of antisocial behaviors

The current investigation utilized a developmental psychopathology approach to test the hypothesis that multigenic (i.e., dopaminergic and serotonergic genes) and multienvironmental factors interactively contribute to developmental pathways of antisocial behavior (ASB). A sample of 8,834 Caucasian individuals from the National Longitudinal Study of Adolescent to Adult Health (Add Health) were used to (a) examine the developmental pathways of ASB from age 13 to 32 using growth mixture modeling, (b) compute weighted multigenic risk scores (Add Health MRS) for ASB from six well-characterized polymorphisms in dopamine and serotonin genes, and (c) test the interaction between the Add Health MRS and a measures of support (incorporating indicators of both positive and negative support from parents and schools). Four pathways of adolescent to adult ASB emerged from the growth mixture models: low, adolescence-peaked, high decline, and persistent. Add Health MRS predicted the persistent ASB pathway, but not other ASB pathways. Males with high Add Health MRS, but not low MRS, had significantly greater odds of being in the adolescence-peaked pathway relative to the low pathway at low levels of school connectedness. Nonfamilial environmental influences during adolescence may have a cumulative impact on the development of ASB, particularly among males with greater underlying genetic risks.

Can a Parenting Intervention to Prevent Early Conduct Problems Interrupt Girls' Risk for Intimate Partner Violence 10 Years Later?

This study tests whether a parenting intervention for families of preschoolers at risk for conduct problems can prevent later risk for intimate partner violence (IPV). Ninety-nine preschoolers at familial risk for conduct problems were randomly assigned to intervention or control conditions. Ten years later, 45 preschoolers and 43 of their siblings completed an assessment of their romantic relationships, including measures of physical and psychological IPV. The study focuses on the 54 females, including targets (n = 27) and siblings (n = 27) who participated in a 10-year follow-up (M age = 16.5, SD = 5.2, range = 10-28). Using an intent-to-treat (ITT) design, multivariate regressions suggest that females from families randomly assigned to intervention in early childhood scored lower than those in the control condition on perceptions of dating violence as normative, beliefs about IPV prevalence, exposure to IPV in their own peer group, and expected sanction behaviors for IPV perpetration and victimization. Findings suggest that early parenting intervention may reduce association of high-risk females with aggressive peers and partners in adolescence.

Does MAOA increase susceptibility to prenatal stress in young children?

BACKGROUND

We previously demonstrated a gene-by-prenatal-environment interaction whereby the monoamine oxidase A gene (MAOA) modified the impact of prenatal tobacco exposure (PTE) on adolescent disruptive behavior (DB), with the MAOA risk genotype varying by sex. We extend this work by examining whether this mechanism is evident with another common adversity, prenatal stress exposure (PSE), and whether sex differences are present earlier in development in closer proximity to exposure.

METHODS

Participants were 281 mothers and their 285 children derived from a prenatal cohort with in-depth prospective measures of PSE and PTE. We assessed DB at age 5 via dimensional developmentally-sensitive measurement. Analyses were stratified by sex based on prior evidence for sex differences.

RESULTS

Concurrent stress exposure predicted DB in children (β=0.310, p=0.001), while main effects of prenatal exposures were seen only in boys. We found a three-way interaction of MAOA×PSE×sex on DB (β=0.813, p=0.022). Boys with MAOA-H had more DB as a function of PSE, controlling for PTE (β=0.774, p=0.015), and as a function of PTE, controlling for PSE (β=0.362, p=0.037). Boys with MAOA-L did not show this susceptibility. MAOA did not interact with PSE (β=-0.133, p=0.561) nor PTE (β=-0.144; p=0.505) in predicting DB in girls. Examination of gene-environment correlation (rGE) showed a correlation between paternal MAOA-L and daughters' concurrent stress exposure (r=-0.240, p=0.013).

DISCUSSION

Findings underscore complex mechanisms linking genetic susceptibility and early adverse exposures. Replication in larger cohorts followed from the pregnancy through adolescence is suggested to elucidate mechanisms that appear to have varying developmental expression.

The Interplay of MAOA and Peer Influences in Predicting Adult Criminal Behavior

Evidence concerning the ability of genetic risk factors to moderate the effects of environments has continued to accumulate over the last decade or so. For the behavioral sciences, this means that genetic risk factors might interact with environmental triggers to influence various human outcomes, including antisocial and aggressive behaviors. The current study seeks to further expand this line of inquiry by examining data drawn from the National Youth Survey Family Study. More specifically, we examined whether a polymorphism in the promoter region of the MAOA gene might condition the influence of exposure to deviant peer groups in the prediction of criminogenic behavior. Our findings offer some mixed evidence that genotype might condition the influence of delinquent peer affiliation on antisocial behavior during the course of human development.

MAOA Influences the Trajectory of Attentional Development

Attention is vital to success in all aspects of life (Meck and Benson, 2002; Erickson et al., 2015), hence it is important to identify biomarkers of later attentional problems early enough to intervene. Our objective was to determine if any of 11 genes (APOE, BDNF, HTR4, CHRNA4, COMT, DRD4, IGF2, MAOA, SLC5A7, SLC6A3, and SNAP25) predicted the trajectory of attentional development within the same group of children between infancy and childhood. We recruited follow up participants from children who participated as infants in visual attention studies and used a similar task at both time points. Using multilevel modeling, we associated changes in the participant’s position in the distribution of scores in infancy to his/her position in childhood with genetic markers on each of 11 genes. While all 11 genes predicted reaction time (RT) residual scores, only Monoamine oxidase A (MAOA) had a significant interaction including time point. We conclude that the MAOA single nucleotide polymorphism (SNP) rs1137070 is useful in predicting which girls are likely to develop slower RTs on an attention task between infancy and childhood. This early identification is likely to be helpful in early intervention.

Time-varying effects of families and peers on adolescent marijuana use: Person-environment interactions across development

Studies have demonstrated that the effects of two well-known predictors of adolescent substance use, family monitoring and antisocial peers, are not static but change over the course of adolescence. Moreover, these effects may differ for different groups of youth. The current study uses time-varying effect modeling to examine the changes in the association between family monitoring and antisocial peers and marijuana use from ages 11 to 19, and to compare these associations by gender and levels of behavioral disinhibition. Data are drawn from the Raising Healthy Children study, a longitudinal panel of 1,040 youth. The strength of association between family monitoring and antisocial peers and marijuana use was mostly steady over adolescence, and was greater for girls than for boys. Differences in the strength of the association were also evident by levels of behavioral disinhibition: youth with lower levels of disinhibition were more susceptible to the influence of parents and peers. Stronger influence of family monitoring on girls and less disinhibited youth was most evident in middle adolescence, whereas the stronger effect of antisocial peers was significant during middle and late adolescence. Implications for the timing and targeting of marijuana preventive interventions are discussed.

Latent trajectories of adolescent antisocial behavior: Serotonin transporter linked polymorphic region (5-HTTLPR) genotype influences sensitivity to perceived parental support

Although prevailing theories of antisocial behavior (ASB) emphasize distinct developmental trajectories, few studies have explored gene–environment interplay underlying membership in empirically derived trajectories. To improve knowledge about the development of overt (e.g., aggression) and covert (e.g., delinquency) ASB, we tested the association of the 44-base pair promoter polymorphism in the serotonin transporter linked polymorphic region gene (5-HTTLPR), perceived parental support (e.g., closeness and warmth), and their interaction with ASB trajectories derived using latent class growth analysis in 2,558 adolescents followed prospectively into adulthood from the National Longitudinal Study of Adolescent Health. Three distinct trajectories emerged for overt (low desisting, adolescent peak, and late onset) and covert ASB (high stable, low stable, and nonoffending). Controlling for sex, parental support inversely predicted membership in the adolescent-peak overt ASB trajectory (vs. low desisting), but was unrelated to class membership for covert ASB. Furthermore, the 5-HTTLPR genotype significantly moderated the association of parental support on overt ASB trajectory membership. It is interesting that the pattern of Gene × Environment interaction differed by trajectory class: whereas short allele carriers were more sensitive to parental support in predicting the late-onset trajectory, the long/long genotype functioned as a potential “plasticity genotype” for the adolescent-peak trajectory group. We discuss these preliminary findings in the context of the differential susceptibility hypothesis and discuss the need for future studies to integrate gene–environment interplay and prospective longitudinal designs.

Sex Differences in Sources of Resilience and Vulnerability to Risk for Delinquency

Research on adolescent risk factors for delinquency has suggested that, due to genetic differences, youth may respond differently to risk factors, with some youth displaying resilience and others a heightened vulnerability. Using a behavioral genetic design and data from the National Longitudinal Study of Adolescent to Adult Health, this study examines whether there are sex differences in the genetic and environmental factors that influence the ways in which adolescents respond to cumulative risk for violent, nonviolent, and overall delinquency in a sample of twins (152 MZ male, 155 MZ female, 140 DZ male, 130 DZ female, and 204 DZ opposite-sex twin pairs). The results revealed that males tended to show greater vulnerability to risk for all types of delinquency, and females exhibited greater resilience. Among males, additive genetic factors accounted for 41, 29, and 43 % of the variance in responses to risk for violent, nonviolent, and overall delinquency, respectively. The remaining proportion of variance in each model was attributed to unique environmental influences, with the exception of 11 % of the variance in nonviolent responses to risk being attributed to common environmental factors. Among females, no significant genetic influences were observed; however, common environmental contributions to differences in the ways females respond to risk for violent, nonviolent, and overall delinquency were 44, 42, and 45 %, respectively. The remaining variance was attributed to unique environmental influences. Overall, genetic factors moderately influenced males' responses to risk while environmental factors fully explain variation in females' responses to risk. The implications of these findings are discussed in the context of improving the understanding of relationships between risks and outcomes, as well as informing policy and practice with adolescent offenders.

The role of the monoamine oxidase A gene in moderating the response to adversity and associated antisocial behavior: a review

Hereditary factors are increasingly attracting the interest of behavioral scientists and practitioners. Our aim in the present article is to introduce some state-of-the-art topics in behavioral genetics, as well as selected findings in the field, in order to illustrate how genetic makeup can modulate the impact of environmental factors. We focus on the most-studied polymorphism to date for antisocial responses to adversity: the monoamine oxidase A gene. Advances, caveats, and promises of current research are reviewed. We also discuss implications for the use of genetic information in applied settings.

The Association Between Peer and own Aggression is Moderated by the BDNF Val-met Polymorphism

Peer antisocial behavior robustly predicts adolescents' own behavior but not all adolescents are equally vulnerable to their peers' influence and genetic factors may confer vulnerability. This study used data of n = 3081 adolescents from the Avon Longitudinal Study of Parents and Children (ALSPAC) to examine whether BDNF, a polymorphism that affects psychological functioning, moderates the association between affiliation with aggressive peers at age 10 and own aggression at age 15. A significant gene-environment interaction was found, where those who affiliated with aggressive peers in childhood showed increased risk for being aggressive in adolescence if they carried the BDNF met-met variant compared to val-val carriers. Our findings underline the importance of both biological and social factors for adolescent development.

MAOA, childhood maltreatment, and antisocial behavior: meta-analysis of a gene-environment interaction

BACKGROUND

In a seminal study of gene-environment interaction, childhood maltreatment predicted antisocial behavior more strongly in male subjects carrying an MAOA promoter variant of lesser, compared with higher, transcriptional efficiency. Many further investigations have been reported, including studies of other early environmental exposures and female subjects. Here, we report a meta-analysis of studies testing the interaction of MAOA genotype and childhood adversities on antisocial outcomes in predominantly nonclinical samples.

METHODS

Included were 27 peer-reviewed, English-language studies published through August, 2012, that contained indicators of maltreatment or other family (e.g., parenting, sociodemographic) hardships; MAOA genotype; indices of aggressive and antisocial behavior; and statistical test of genotype-environment interaction. Studies of forensic and exclusively clinical samples, clinical cohorts lacking proportionally matched control subjects, or outcomes nonspecific for antisocial behavior were excluded. The Liptak-Stouffer weighted Z-test for meta-analysis was implemented to maximize study inclusion and calculated separately for male and female cohorts.

RESULTS

Across 20 male cohorts, early adversity presaged antisocial outcomes more strongly for low-activity, relative to high- activity, MAOA genotype (p = .0044). Stratified analyses showed the interaction specific to maltreatment (p = .00000082) and robust to several sensitivity analyses. Across 11 female cohorts, MAOA did not interact with combined early life adversities, whereas maltreatment alone predicted antisocial behaviors preferentially, but weakly, in female subjects of high-activity MAOA genotype (p = .02).

CONCLUSIONS

We found common regulatory variation in MAOA to moderate effects of childhood maltreatment on male antisocial behaviors, confirming a sentinel finding in research on gene-environment interaction. An analogous, but less consistent, finding in female subjects warrants further investigation.

Dopamine receptor D4 gene moderates the effect of positive and negative peer experiences on later delinquency: The Tracking Adolescents' Individual Lives Survey study

The quality of adolescents' relationships with peers can have a lasting impact on later psychosocial adjustment, mental health, and behavior. However, the effect of peer relations on later problem behavior is not uniformly strong, and genetic factors might influence this association. This study used four-wave longitudinal (11–19 years) data (n = 1,151) from the Tracking Adolescents' Individual Lives Survey, a Dutch cohort study into adolescent development to test whether the dopamine receptor D4 polymorphism moderates the impact of negative (i.e., victimization) and positive peer experiences (i.e., social well-being) on later delinquency. Contrary to our expectations, results showed that carriers of the dopamine receptor D4 gene 4-repeat homozygous variant instead of those carrying the 7-repeat allele were more susceptible to the effects of both peer victimization and social well-being on delinquency later in adolescence. Findings of our study are discussed in light of other studies into genetic moderation of peer effects on adolescent development and the possibility that developmental specifics in adolescence, such as maturation processes in brain structure and functioning, may affect the interplay of environmental and genetic factors in this period in life.

Genetic and environmental influences on affiliation with deviant peers during adolescence and early adulthood

Adolescence and early adulthood is a time when peer groups become increasingly influential in the lives of young people. Youths exposed to deviant peers risk susceptibility to externalizing behaviors and related psychopathology. In addition to environmental correlates of deviant peer affiliation, a growing body of evidence has suggested that affiliation with deviant peers is heritable. This study examined the magnitude of genetic and environmental influences on affiliation with deviant peers, changes in the relative importance of these factors, and which of these factors contribute to the stability of affiliation across this critical developmental period using a longitudinal twin study design that assessed same-sex twins (485 monozygotic pairs, 271 dizygotic pairs) at 3 discrete ages: 15, 18, and 21 years of age. Biometric models revealed that genetic influences increased with age. New genetic influences appeared during late adolescence, and no new genetic influences emerged by age 21. Environmental influences shared by sibling pairs decreased with age, while the proportion of nonshared environmental effects unique to each individual remained relatively stable over the course of development. Shared environmental influences were largely age-overlapping, whereas nonshared environmental influences were largely age-specific. In summary, this study found variance in affiliation with deviant peers is explained by shared and nonshared environment effects as well as by genetic influences (46% by age 21), supporting the role of genetically influenced selection factors. The shared environment was almost exclusively responsible for the stability in late adolescence, while genetic influences were primarily responsible for stability in early adulthood.

Parenting as a reaction evoked by children's genotype: a meta-analysis of children-as-twins studies

Parenting has been extensively studied but mostly as a causal factor influencing child outcomes. The aim of the current article is to examine the child's side of the relationship by meta-analyzing studies which used quantitative genetic methods that provide leverage in understanding causality. A meta-analysis of 32 children-as-twins studies of parenting revealed a heritability estimate of 23%, thus indicating that genetically influenced behaviors of the child affect and shape parental behavior. The shared- and nonshared-environmental estimates, which amounted to 43% and 34%, respectively, indicate not only substantial consistency in parental behavior but also differential treatment within the family. Assessment method, age, and parenting dimension were found to be significant moderators of these influences. Our findings stress the importance of accounting for genotype-environment correlations in child-development studies and call into question previous research that interpreted correlational results in unidirectional terms with parenting as the sole causal factor.

Gene-environment interactions in the etiology of human violence

This chapter reviews the current research on gene-environment interactions (G × E) with regard to human violence. Findings are summarized from both behavioral and molecular genetic studies that have investigated the interplay of genetic and environmental factors in terms of influencing violence-related behavior. Together, these studies reveal promising evidence that genetic factors combine with environmental influences to impact on the development of violent behavior and related phenotypes. G × E have been identified for a number of candidate genes implicated in violence. Moreover, the reviewed G × E were found to extend to a broad range of environmental characteristics, including both adverse and favorable conditions. As has been the case with other G × E research, findings have been mixed, with considerable heterogeneity between studies. Lack of replication together with serious methodological limitations remains a major challenge for drawing definitive conclusions about the nature of violence-related G × E. In order to fulfill its potential, it is recommended that future G × E research needs to shift its focus to dissecting the neural mechanisms and the underlying pathophysiological pathways by which genetic variation may influence differential susceptibility to environmental exposures.

Unraveling the genetic etiology of adult antisocial behavior: a genome-wide association study

Crime poses a major burden for society. The heterogeneous nature of criminal behavior makes it difficult to unravel its causes. Relatively little research has been conducted on the genetic influences of criminal behavior. The few twin and adoption studies that have been undertaken suggest that about half of the variance in antisocial behavior can be explained by genetic factors. In order to identify the specific common genetic variants underlying this behavior, we conduct the first genome-wide association study (GWAS) on adult antisocial behavior. Our sample comprised a community sample of 4816 individuals who had completed a self-report questionnaire. No genetic polymorphisms reached genome-wide significance for association with adult antisocial behavior. In addition, none of the traditional candidate genes can be confirmed in our study. While not genome-wide significant, the gene with the strongest association (p-value = 8.7×10(-5)) was DYRK1A, a gene previously related to abnormal brain development and mental retardation. Future studies should use larger, more homogeneous samples to disentangle the etiology of antisocial behavior. Biosocial criminological research allows a more empirically grounded understanding of criminal behavior, which could ultimately inform and improve current treatment strategies.

Prevention of serious conduct problems in youth with attention deficit/hyperactivity disorder

The purpose of this review is to discuss issues in the prevention of serious conduct problems among children and adolescents with attention deficit/hyperactivity disorder (ADHD). The authors began by reviewing research on the common genetic and environmental etiological factors, developmental trajectories, characteristics and impairments associated with ADHD and comorbid oppositional defiant and conduct disorders. Next, the authors presented empirically based models for intervention with children and adolescents with ADHD that are at risk of developing serious conduct problems and detailed the evidence supporting these models. Researchers have demonstrated the utility of medication and psychosocial intervention approaches to treat youth with these problems, but current evidence appears to support the superiority of multimodal treatments that include both approaches. Future directions for researchers are discussed.