Differential susceptibility to rearing environment depending on dopamine-related genes: new evidence and a meta-analysis

Externalizing Problem Behavior in Adolescence: Parenting Interacting With DAT1 and DRD4 Genes

This study extends previous gene-by-environment (G × E) research through design and methodological advances and examines alternative hypotheses of diathesis stress, vantage sensitivity, and differential susceptibility. In a sample of 984 adolescents and their parents, we examined whether effects of parental support, proactive, punitive, harsh punitive, and psychological control on externalizing problem behavior are moderated by adolescents' genotype for the dopamine transporter (DAT1) or receptor D4 (DRD4) gene. Results provided evidence for main effects of parenting behavior and DRD4, and multiple interaction effects of which one survived Bonferroni correction. Adolescents carrying a long DRD4 variant were more susceptible to the effects of parental proactive control on aggression, for better and for worse. Critical considerations were made regarding the complexity of G × E research.

Testing differential susceptibility: Plasticity genes, the social environment, and their interplay in adolescent response inhibition

OBJECTIVES

Impaired inhibitory control is a key feature of attention-deficit/hyperactivity disorder (ADHD). We investigated gene-environment interaction (GxE) as a possible contributing factor to response inhibition variation in context of the differential susceptibility theory. This states individuals carrying plasticity gene variants will be more disadvantaged in negative, but more advantaged in positive environments.

METHODS

Behavioural and neural measures of response inhibition were assessed during a Stop-signal task in participants with (N = 197) and without (N = 295) ADHD, from N = 278 families (age M = 17.18, SD =3.65). We examined GxE between candidate plasticity genes (DAT1, 5-HTT, DRD4) and social environments (maternal expressed emotion, peer affiliation).

RESULTS

A DRD4 × Positive peer affiliation interaction was found on the right fusiform gyrus (rFG) activation during successful inhibition. Further, 5-HTT short allele carriers showed increased rFG activation during failed inhibitions. Maternal warmth and positive peer affiliation were positively associated with right inferior frontal cortex activation during successful inhibition. Deviant peer affiliation was positively related to the error rate.

CONCLUSIONS

While a pattern of differential genetic susceptibility was found, more clarity on the role of the FG during response inhibition is warranted before firm conclusions can be made. Positive and negative social environments were related to inhibitory control. This extends previous research emphasizing adverse environments.

Music genetics research: Association with musicality of a polymorphism in the AVPR1A gene

Musicality is defined as a natural tendency, sensibility, knowledge, or talent to create, perceive, and play music. Musical abilities involve a great range of social and cognitive behaviors, which are influenced by both environmental and genetic factors. Although a number of studies have yielded insights into music genetics research, genes and biological pathways related to these traits are not fully understood. Our hypothesis in the current study is that genes associated with different behaviors could also influence the musical phenotype. Our aim was to investigate whether polymorphisms in six genes (AVPR1A, SLC6A4, ITGB3, COMT, DRD2 and DRD4) related to social and cognitive traits are associated with musicality in a sample of children. Musicality was assessed through an individualized music therapy assessment profile (IMTAP) which has been validated in Brazil to measure musical ability. We show here that the RS1 microsatellite of the AVPR1A gene is nominally associated with musicality, corroborating previous results linking AVPR1A with musical activity. This study is one of the first to investigate musicality in a comprehensive way, and it contributes to better understand the genetic basis underlying musical ability.

Chronic Stressors and Adolescents' Externalizing Problems: Genetic Moderation by Dopamine Receptor D4. The TRAILS Study

The existing literature does not provide consistent evidence that carriers of the Dopamine D4 Receptor 7-repeat allele are more sensitive to adverse environmental influences, resulting in enhanced externalizing problems, compared to noncarriers. One explanation is that the adverse influences examined in prior studies were not severe, chronic, or distressing enough to reveal individual differences in sensitivity reflected by DRD4–7R. This study examined whether the 7-repeat allele moderated the association between chronic stressors capturing multiple stressful aspects of individuals’ lives and externalizing problems in adolescence. We expected that chronic stressor levels would be associated with externalizing levels only in 7-repeat carriers. Using Linear Mixed Models, we analyzed data from 1621 Dutch adolescents (52.2% boys), obtained in three measurement waves (mean age approximately 11, 13.5, and 16 years) from the TRacking Adolescents’ Individual Lives Survey (TRAILS) population-based birth cohort and the parallel clinic-referred cohort. Across informants, we found that higher levels of chronic stressors were related to higher externalizing levels in 7-repeat carriers but not in noncarriers, as hypothesized. Although previous studies on the 7-repeat allele as a moderator of environmental influences on adolescents’ externalizing problems have not convincingly demonstrated individual differences in sensitivity to adverse environmental influences, our findings suggest that adolescent carriers of the Dopamine D4 Receptor 7-repeat allele are more sensitive to chronic, multi-context stressors than noncarriers.

Adolescent externalizing behaviour, psychological control, and peer rejection: Transactional links and dopaminergic moderation

This study investigated (1) reciprocal links among parental psychological control, peer rejection, and adolescent externalizing (aggressive and rule-breaking behaviour), and (2) the moderating effect of an adolescent genetic factor (biologically informed polygenic score for dopamine signalling). Three-year longitudinal data from 1,116 adolescents (51% boys; M age = 13.79) and their parents included psychological measures (adolescent-reported psychological control, peer-reported rejection, and parent-reported aggressive and rule-breaking behaviour). Cross-lagged analyses showed bidirectional effects between psychological control and both aggressive and rule-breaking behaviour and a unidirectional effect of peer rejection on both forms of problem behaviour over time. Multigroup structural equation modelling revealed genetic moderation only for rule-breaking behaviour: for adolescents with intermediate levels of dopamine signalling significant environmental effects were present, whereas adolescent effects of rule-breaking behaviour on psychological control were significant for adolescents with both intermediate and high profiles and effects on peer rejection only for adolescents with high dopamine profiles. Statement of contribution What is already known on this subject? Parental psychological control is related to adolescent externalizing problems. Experiencing peer rejection reinforces aggressive and rule-breaking behaviour. Single-gene studies show that dopaminergic genes influence externalizing problems directly or in interaction with the environment. What does this study add? Parental psychological control and adolescent aggressive and rule-breaking behaviour exacerbate one another longitudinally. Longitudinal associations between peer rejection and both subtypes of externalizing behaviour are unidirectional. With a polygenic approach, dopaminergic moderation is present for rule-breaking behaviour only.

Interactions of adolescent social experiences and dopamine genes to predict physical intimate partner violence perpetration

Objectives

We examined the interactions between three dopamine gene alleles (DAT1, DRD2, DRD4) previously associated with violent behavior and two components of the adolescent environment (exposure to violence, school social environment) to predict adulthood physical intimate partner violence (IPV) perpetration among white men and women.

Methods

We used data from Wave IV of the National Longitudinal Study of Adolescent to Adult Health, a cohort study following individuals from adolescence to adulthood. Based on the prior literature, we categorized participants as at risk for each of the three dopamine genes using this coding scheme: two 10-R alleles for DAT1; at least one A-1 allele for DRD2; at least one 7-R or 8-R allele for DRD4. Adolescent exposure to violence and school social environment was measured in 1994 and 1995 when participants were in high school or middle school. Intimate partner violence perpetration was measured in 2008 when participants were 24 to 32 years old. We used simple and multivariable logistic regression models, including interactions of genes and the adolescent environments for the analysis.

Results

Presence of risk alleles was not independently associated with IPV perpetration but increasing exposure to violence and disconnection from the school social environment was associated with physical IPV perpetration. The effects of these adolescent experiences on physical IPV perpetration varied by dopamine risk allele status. Among individuals with non-risk dopamine alleles, increased exposure to violence during adolescence and perception of disconnection from the school environment were significantly associated with increased odds of physical IPV perpetration, but individuals with high risk alleles, overall, did not experience the same increase.

Conclusion

Our results suggested the effects of adolescent environment on adulthood physical IPV perpetration varied by genetic factors. This analysis did not find a direct link between risk alleles and violence, but contributes to growing research indicating that if genetic factors contribute to perpetration, this relationship is likely complicated and the result of interactions with other factors.

Genetic Correlates of Spirituality/Religion and Depression: A Study in Offspring and Grandchildren at High and Low Familial Risk for Depression

RATIONALE

Possible genetic correlates of spirituality and depression have been identified in community samples. We investigate some of the previously identified candidates in a sample of families at both high and low-risk for depression.

METHOD

Offspring and grandchildren of individuals at high and low-risk for depression, participating in a multi-wave thirty-year longitudinal study, were assessed for seven SNPS drawn from four single gene candidates associated with systems implicated in both depression and spirituality: Serotonin (5-HT1B and 5-HT2A), Dopamine (DRD2), Oxytocin (OT) and Monoamine Vesicular Transporter (VMAT1).

RESULTS

Dopamine (DRD2) Serotonin (5-HT1B), their Transporter (VMAT1) and Oxytocin (OXTR) were positively associated with a high level of importance of spirituality or religion (S/R) in the group at low familial risk for depression. DRD2 minor allele was associated with both lifetime major depressive disorder (MDD) and spirituality in the low-risk group for depression. No SNPs were related to S/R in the group at high familial risk for depression. OXTR was associated with lifetime MDD in the full sample.

CONCLUSION

Genes for dopamine, serotonin, their vesicular transporter, and oxytocin may be associated with S/R in people at low familial risk for depression. Genes for dopamine may be associated both with S/R and increased risk for depression in people at low-risk for depression, suggesting a common pathway or physiology to mild to moderate depression. MDD is associated with oxytocin across risk groups. In the high-risk group, phenotypic expression of S/R may be suppressed.

IMPLICATIONS

The shared association of DRD2 by S/R and depression, generally found to be inversely related, calls for further research on their common physiological pathways, and the phenotypic expression of these pathways based upon use and environment. Prevention for offspring at high familial risk for depression might include support for the development of child spirituality.

Links between early baseline cortisol, attachment classification, and problem behaviors: A test of differential susceptibility versus diathesis-stress

The purpose of the current study was to predict concurrent levels of problem behaviors from young children's baseline cortisol and attachment classification, a proxy for the quality of caregiving experienced. In a sample of 58 children living at or below the federal poverty threshold, children's baseline cortisol levels, attachment classification, and problem behaviors were assessed at 17 months of age. We hypothesized that an interaction between baseline cortisol and attachment classification would predict problem behaviors above and beyond any main effects of baseline cortisol and attachment. However, based on limited prior research, we did not predict whether or not this interaction would be more consistent with diathesis-stress or differential susceptibility models. Consistent with diathesis-stress theory, the results indicated no significant differences in problem behavior levels among children with high baseline cortisol. In contrast, children with low baseline cortisol had the highest level of problem behaviors in the context of a disorganized attachment relationship. However, in the context of a secure attachment relationship, children with low baseline cortisol looked no different, with respect to problem behavior levels, then children with high cortisol levels. These findings have substantive implications for the socioemotional development of children reared in poverty.

A DRD4 gene by maternal sensitivity interaction predicts risk for overweight or obesity in two independent cohorts of preschool children

BACKGROUND

Recent evidence suggests that early exposure to low maternal sensitivity is a risk factor for obesity in children and adolescents. A separate line of study shows that the seven-repeat (7R) allele of the dopamine-4 receptor gene (DRD4) increases susceptibility to environmental factors including maternal sensitivity. The current study integrates these lines of work by examining whether preschoolers carrying the 7R allele are more vulnerable to low maternal sensitivity as it relates to overweight/obesity risk.

METHOD

The Maternal Adversity Vulnerability and Neurodevelopment (MAVAN) project in Canada was used as the discovery cohort (N = 203), while the Generation R study in the Netherlands was used as a replication sample (N = 270). Regression models to predict both continuous BMI z-scores and membership in any higher BMI category based on established World Health Organization (WHO) cutoffs for 48 months of age were completed.

RESULTS

In both cohorts, there was a significant maternal sensitivity by DRD4 by sex interaction predicting higher body mass indices and/or obesity risk. As hypothesized, post hoc testing revealed an inverse relationship between maternal sensitivity and body mass indices in 7R allele carriers relative to noncarriers. This finding was strongest in girls in the Canadian cohort and in boys in the Dutch cohort.

CONCLUSIONS

Many children who carry the 7R allele of DRD4 appear to be more influenced by maternal sensitivity as it relates to overweight/obesity risk, consistent with a plasticity effect. Given the relatively small sample sizes available for these analyses, further replications will be needed to confirm and extend these results.

Vulnerability or Sensitivity to the Environment? Methodological Issues, Trends, and Recommendations in Gene-Environment Interactions Research in Human Behavior

Research on the potential role of gene-environment interactions (GxE) in explaining vulnerability to psychopathology in humans has witnessed a shift from a diathesis-stress perspective to differential susceptibility approaches. This paper critically reviews methodological issues and trends in this body of research. Databases were screened for studies of GxE in the prediction of personality traits, behavior, and mental health disorders in humans published between January 2002 and January 2015. In total, 315 papers were included. Results showed that 34 candidate genes have been included in GxE studies. Independent of the type of environment studied (early or recent life events, positive or negative environments), about 67-83% of studies have reported significant GxE interactions, which is consistent with a social susceptibility model. The percentage of positive results does not seem to differ depending on the gene studied, although publication bias might be involved. However, the number of positive findings differs depending on the population studied (i.e., young adults vs. older adults). Methodological considerations limit the ability to draw strong conclusions, particularly as almost 90% (n = 283/315) of published papers are based on samples from North America and Europe, and about 70% of published studies (219/315) are based on samples that were also used in other reports. At the same time, there are clear indications of methodological improvements over time, as is shown by a significant increase in longitudinal and experimental studies as well as in improved minimum genotyping. Recommendations for future research, such as minimum quality assessment of genes and environmental factors, specifying theoretical models guiding the study, and taking into account of cultural, ethnic, and lifetime perspectives, are formulated.

A systematic review and secondary data analysis of the interactions between the serotonin transporter 5-HTTLPR polymorphism and environmental and psychological factors in eating disorders

OBJECTIVES

To summarize and synthesize the growing gene x environment (GxE) research investigating the promoter region of the serotonin transporter gene (5-HTTLPR) in the eating disorders (ED) field, and overcome the common limitation of low sample size, by undertaking a systematic review followed by a secondary data meta-analysis of studies identified by the review.

METHOD

A systematic review of articles using PsycINFO, PubMed, and EMBASE was undertaken to identify studies investigating the interaction between 5-HTTLPR and an environmental or psychological factor, with an ED-related outcome variable. Seven studies were identified by the systematic review, with complete data sets of five community (n = 1750, 64.5% female) and two clinical (n = 426, 100% female) samples combined to perform four secondary-data analyses: 5-HTTLPR x Traumatic Life Events to predict ED status (n = 909), 5-HTTLPR x Sexual and Physical Abuse to predict bulimic symptoms (n = 1097), 5-HTTLPR x Depression to predict bulimic symptoms (n = 1256), and 5-HTTLPR x Impulsiveness to predict disordered eating (n = 1149).

RESULTS

Under a multiplicative model, the low function (s) allele of 5-HTTLPR interacted with traumatic life events and experiencing both sexual and physical abuse (but not only one) to predict increased likelihood of an ED and bulimic symptoms, respectively. However, under an additive model there was also an interaction between sexual and physical abuse considered independently and 5-HTTLPR, and no interaction with traumatic life events. No other GxE interactions were significant.

CONCLUSION

Early promising results should be followed-up with continued cross-institutional collaboration in order to achieve the large sample sizes necessary for genetic research.

Application of environmental sensitivity theories in personalized prevention for youth substance abuse: a transdisciplinary translational perspective

Preventive interventions that target high-risk youth, via one-size-fits-all approaches, have demonstrated modest effects in reducing rates of substance use. Recently, substance use researchers have recommended personalized intervention strategies. Central to these approaches is matching preventatives to characteristics of an individual that have been shown to predict outcomes. One compelling body of literature on person × environment interactions is that of environmental sensitivity theories, including differential susceptibility theory and vantage sensitivity. Recent experimental evidence has demonstrated that environmental sensitivity (ES) factors moderate substance abuse outcomes. We propose that ES factors may augment current personalization strategies such as matching based on risk factors/severity of problem behaviors (risk severity (RS)). Specifically, individuals most sensitive to environmental influence may be those most responsive to intervention in general and thus need only a brief-type or lower-intensity program to show gains, while those least sensitive may require more comprehensive or intensive programming for optimal responsiveness. We provide an example from ongoing research to illustrate how ES factors can be incorporated into prevention trials aimed at high-risk adolescents.

Executive Function Mediates the Relations between Parental Behaviors and Children's Early Academic Ability

The past decade has witnessed a growth of interest in parental influences on individual differences in children's executive function (EF) on the one hand and in the academic consequences of variation in children's EF on the other hand. The primary aim of this longitudinal study was to examine whether children's EF mediated the relation between three distinct aspects of parental behavior (i.e., parental scaffolding, negative parent-child interactions, and the provision of informal learning opportunities) and children's academic ability (as measured by standard tests of literacy and numeracy skills). Data were collected from 117 parent-child dyads (60 boys) at two time points ~1 year apart (M Age at Time 1 = 3.94 years, SD = 0.53; M Age at Time 2 = 5.11 years, SD = 0.54). At both time points children completed a battery of tasks designed to measure general cognitive ability (e.g., non-verbal reasoning) and EF (e.g., inhibition, cognitive flexibility, working memory). Our models revealed that children's EF (but not general cognitive ability) mediated the relations between parental scaffolding and negative parent-child interactions and children's early academic ability. In contrast, parental provision of opportunities for learning in the home environment was directly related to children's academic abilities. These results suggest that parental scaffolding and negative parent-child interactions influence children's academic ability by shaping children's emerging EF.

Diminished ability to identify facial emotional expressions in children with disorganized attachment representations

The development of children's ability to identify facial emotional expressions has long been suggested to be experience dependent, with parental caregiving as an important influencing factor. This study attempts to further this knowledge by examining disorganization of the attachment system as a potential psychological mechanism behind aberrant caregiving experiences and deviations in the ability to identify facial emotional expressions. Typically developing children (N = 105, 49.5% boys) aged 6-7 years (M = 6 years 8 months, SD = 1.8 months) completed an attachment representation task and an emotion identification task, and parents rated children's negative emotionality. The results showed a generally diminished ability in disorganized children to identify facial emotional expressions, but no response biases. Disorganized attachment was also related to higher levels of negative emotionality, but discrimination of emotional expressions did not moderate or mediate this relation. Our novel findings relate disorganized attachment to deviations in emotion identification, and therefore suggest that disorganization of the attachment system may constitute a psychological mechanism linking aberrant caregiving experiences to deviations in children's ability to identify facial emotional expressions. Our findings further suggest that deviations in emotion identification in disorganized children, in the absence of maltreatment, may manifest in a generally diminished ability to identify emotional expressions, rather than in specific response biases.

An Evolutionary Perspective on Family Studies: Differential Susceptibility to Environmental Influences

An evolutionary perspective of human development provides the basis for the differential-susceptibility hypothesis which stipulates that individuals should differ in their susceptibility to environmental influences, with some being more affected than others by both positive and negative developmental experiences and environmental exposures. This paper reviews evidence consistent with this claim while revealing that temperamental and genetic characteristics play a role in distinguishing more and less susceptible individuals. The differential-susceptibility framework under consideration is contrasted to the traditional diathesis-stress view that "vulnerability" traits predispose some to being disproportionately affected by (only) adverse experiences. We raise several issues stimulated by the literature that need to be clarified in further research. Lastly, we suggest that therapy may differ in its effects depending on an individual's susceptibility.

Nature, Nurture, and Their Interplay

Cultural neuroscience research examines how psychological processes are affected by the interplay between culture and biological factors, including genetic influences, patterns of neural activation, and physiological processes. In this review, we present foundational and current empirical research in this area, and we also discuss theories that aim to explain how various aspects of the social environment are interpreted as meaningful in different cultures and interact with a cascade of biological processes to ultimately influence thoughts and behaviors. This review highlights theoretical and methodological issues, potential solutions, and future implications for a field that aspires to integrate the complexities of human biology with the richness of culture.

Psychiatric Genetics in Child Custody Proceedings: Ethical, Legal, and Social Issues

This paper considers the ethical, legal, and social issues raised by the prospect of increasing use of psychiatric genetic data in child custody litigation. Although genetic tests cannot currently confirm a parent or child's psychiatric diagnosis, it is likely that as relevant findings emerge, they will be introduced in family courts to challenge parental capacity. Here, we draw on three projected, but plausible, scenarios for obtaining psychiatric data about parents -- imposed genetic testing, access to medical records, and genetic theft -- then consider the use of psychiatric genetic data of children, to highlight the issues that judges, child custody evaluators, and clinicians who may provide treatment for parents or children with mental health issues will need to consider. These include: genetic privacy, stigma, genetic surveillance, and judicial and health professionals' bias. We argue that the unchecked introduction of psychiatric genetic data may have a detrimental effect on the administration of justice. In particular, the article highlights the risk that the (mis)use of psychiatric genetic data in custody disputes would 1) exacerbate stigma and treatment-avoidance among parents and incentivize privacy violations to pressure parents to relinquish parental rights; 2) disproportionately affect poor parents and single mothers of color involved with Child Protective Services; and 3) detract attention from social and environmental factors impacting mental health to the detriment of the families involved. Awareness of these issues and an understanding of the meaning of genomic data by judges and custody evaluators will be pivotal in ensuring that justice is served.

Exploring genetic moderators and epigenetic mediators of contextual and family effects: From Gene × Environment to epigenetics

In the current manuscript, we provide an overview of a research program at the University of Georgia's Center for Family Research designed to expand upon rapid and ongoing developments in the fields of genetics and epigenetics. By placing those developments in the context of translational research on family and community determinants of health and well-being among rural African Americans, we hope to identify novel, modifiable environments and biological processes. In the first section of the article, we review our earlier work on genotypic variation effects on the association between family context and mental and physical health outcomes as well as differential responses to family-based intervention. We then transition to discuss our more recent research on the association of family and community environments with epigenetic processes. In this second section of the article, we begin by briefly reviewing terminology and basic considerations before describing evidence that early environments may influence epigenetic motifs that potentially serve as mediators of long-term effects of early family and community environments on longer term health outcomes. We also provide evidence that genotype may sometimes influence epigenetic outcomes. Finally, we describe our recent efforts to use genome-wide characterization of epigenetic patterns to better understand the biological impact of protective parenting on long-term shifts in inflammatory processes and its potential implications for young adult health. As will be clear, research on epigenetics as a mediator of the connections between family/community processes and a range of health outcomes is still in its infancy, but the potential to develop important insights regarding mechanisms linking modifiable environments to biological processes and long-term health outcomes already is coming into view.

Infant temperamental reactivity, maternal and grandparental sensitivity: Differential susceptibility for behavior problems in China

BACKGROUND

The differential susceptibility hypothesis suggests that children's innate characteristics and their rearing experiences interact differentially during development. Recently, the study of interactions between infants' temperament and rearing experiences has become a research hotspot. In China, grandparental care is a very common phenomenon, with many infants taken care of by grandparents while mothers are out for work.

AIM

To investigate whether the associations between maternal and grandmaternal sensitivity, and behavior problems were moderated by infant temperamental reactivity, while the infants were raised by both their mothers and grandmothers.

SUBJECTS

A total of 71 infants (average age of 17.6months), their mothers and grandmothers were included in this study.

OUTCOME MEASURES

Maternal sensitivity and grandmaternal sensitivity were assessed with the Maternal Behavior Q-sort-Chinese Version, infants' temperamental reactivity was measured with Carey's Toddler Temperament Questionnaire-Chinese Revision, and infants' behavior problems were measured with the Infant-Toddler Social and Emotional Assessment-Chinese Version.

RESULTS

Maternal sensitivity significantly predicted infants' impulsivity and aggression. Infants' temperamental reactivity moderated the effect of maternal sensitivity on infants' general anxiety. In addition, infant temperamental reactivity moderated the impact of grandmaternal sensitivity on infants' separation distress.

CONCLUSIONS

Our results support the differential susceptibility hypothesis to some extent. Infants with high temperamental reactivity not only suffer more from low maternal and grandmaternal sensitivity, but also benefit more from high maternal and grandmaternal sensitivity as compared to those infants with low temperamental reactivity.

Genetic Moderation of Intervention Efficacy: Dopaminergic Genes, The Incredible Years, and Externalizing Behavior in Children

This study investigated whether children scoring higher on a polygenic plasticity index based on five dopaminergic genes (DRD4, DRD2, DAT1, MAOA, and COMT) benefited the most from the Incredible Years (IY) parent program. Data were used from a randomized controlled trial including 341 Dutch families with 4- to 8-year-old children (55.7% boys) showing moderate to high levels of problem behavior. IY proved to be most effective in decreasing parent-reported (but not observed) externalizing behavior in boys (but not girls) carrying more rather than fewer dopaminergic plasticity alleles; this Gene × Intervention effect was most pronounced in the case of boys whose parents' manifested the most positive change in parenting in response to the intervention. These results proved robust across a variety of sampling specifications (e.g., intention to treat, ethnicity).

Beyond main effects of gene-sets: harsh parenting moderates the association between a dopamine gene-set and child externalizing behavior

BACKGROUND

In a longitudinal cohort study, we investigated the interplay of harsh parenting and genetic variation across a set of functionally related dopamine genes, in association with children's externalizing behavior. This is one of the first studies to employ gene-based and gene-set approaches in tests of Gene by Environment (G × E) effects on complex behavior. This approach can offer an important alternative or complement to candidate gene and genome-wide environmental interaction (GWEI) studies in the search for genetic variation underlying individual differences in behavior.

METHODS

Genetic variants in 12 autosomal dopaminergic genes were available in an ethnically homogenous part of a population-based cohort. Harsh parenting was assessed with maternal (n = 1881) and paternal (n = 1710) reports at age 3. Externalizing behavior was assessed with the Child Behavior Checklist (CBCL) at age 5 (71 ± 3.7 months). We conducted gene-set analyses of the association between variation in dopaminergic genes and externalizing behavior, stratified for harsh parenting.

RESULTS

The association was statistically significant or approached significance for children without harsh parenting experiences, but was absent in the group with harsh parenting. Similarly, significant associations between single genes and externalizing behavior were only found in the group without harsh parenting. Effect sizes in the groups with and without harsh parenting did not differ significantly. Gene-environment interaction tests were conducted for individual genetic variants, resulting in two significant interaction effects (rs1497023 and rs4922132) after correction for multiple testing.

CONCLUSION

Our findings are suggestive of G × E interplay, with associations between dopamine genes and externalizing behavior present in children without harsh parenting, but not in children with harsh parenting experiences. Harsh parenting may overrule the role of genetic factors in externalizing behavior. Gene-based and gene-set analyses offer promising new alternatives to analyses focusing on single candidate polymorphisms when examining the interplay between genetic and environmental factors.

Interactive effects of attachment and FKBP5 genotype on school-aged children's emotion regulation and depressive symptoms

Attachment insecurity is influenced by both environmental and genetic factors, but few studies have examined the effects of gene-environment interactions. In the context of environmental stress, a functional variant in the glucocorticoid receptor co-chaperone FKBP5 gene has been repeatedly shown to increase risk for psychiatric illness, including depression. We expand on prior work by exploring cross-sectional attachment by gene effects on both attachment insecurity and downstream physiological and behavioral measures in a diverse community sample of school-aged children (N=99, 49% girls, M_age=10.29years, 66.6% non-White) and their mothers. Specifically, we examined moderating effects of FKBP5 rs3800373 genotype on the links between parenting insensitivity (overcontrol) and child attachment. Further, we assessed whether FKBP5 moderates the links between maternal and child attachment and children's emotion regulation self-report, respiratory sinus arrhythmia (RSA) in response to a standardized laboratory stressor, and depressive symptoms. Higher levels of overcontrol predicted lower child attachment security only in FKBP5 minor allele carriers. Among children with two minor alleles (CC), attachment security was negatively associated with emotion suppression, rumination, depressive symptoms, and RSA reactivity; similarly, for these children, maternal attachment anxiety was positively associated with depressive symptoms. The findings can be conceptualized in a differential susceptibility framework, where the FKBP5 minor allele confers either risk or resilience, depending on the parenting environment.

A Test-Replicate Approach to Candidate Gene Research on Addiction and Externalizing Disorders: A Collaboration Across Five Longitudinal Studies

This study presents results from a collaboration across five longitudinal studies seeking to test and replicate models of gene-environment interplay in the development of substance use and externalizing disorders (SUDs, EXT). We describe an overview of our conceptual models, plan for gene-environment interplay analyses, and present main effects results evaluating six candidate genes potentially relevant to SUDs and EXT (MAOA, 5-HTTLPR, COMT, DRD2, DAT1, and DRD4). All samples included rich longitudinal and phenotypic measurements from childhood/adolescence (ages 5-13) through early adulthood (ages 25-33); sample sizes ranged from 3487 in the test sample, to ~600-1000 in the replication samples. Phenotypes included lifetime symptom counts of SUDs (nicotine, alcohol and cannabis), adult antisocial behavior, and an aggregate externalizing disorder composite. Covariates included the first 10 ancestral principal components computed using all autosomal markers in subjects across the data sets, and age at the most recent assessment. Sex, ancestry, and exposure effects were thoroughly evaluated. After correcting for multiple testing, only one significant main effect was found in the test sample, but it was not replicated. Implications for subsequent gene-environment interplay analyses are discussed.

Prenatal maternal depression and child serotonin transporter linked polymorphic region (5-HTTLPR) and dopamine receptor D4 (DRD4) genotype predict negative emotionality from 3 to 36 months

Prenatal maternal depression and a multilocus genetic profile of two susceptibility genes implicated in the stress response were examined in an interaction model predicting negative emotionality in the first 3 years. In 179 mother-infant dyads from the Maternal Adversity, Vulnerability, and Neurodevelopment cohort, prenatal depression (Center for Epidemiologic Studies Depressions Scale) was assessed at 24 to 36 weeks. The multilocus genetic profile score consisted of the number of susceptibility alleles from the serotonin transporter linked polymorphic region gene (5-HTTLPR): no long-rs25531(A) (LA: short/short, short/long-rs25531(G) [LG], or LG/LG] vs. any LA) and the dopamine receptor D4 gene (six to eight repeats vs. two to five repeats). Negative emotionality was extracted from the Infant Behaviour Questionnaire-Revised at 3 and 6 months and the Early Child Behavior Questionnaire at 18 and 36 months. Mixed and confirmatory regression analyses indicated that prenatal depression and the multilocus genetic profile interacted to predict negative emotionality from 3 to 36 months. The results were characterized by a differential susceptibility model at 3 and 6 months and by a diathesis-stress model at 36 months.

Molecular Signatures of Natural Selection for Polymorphic Genes of the Human Dopaminergic and Serotonergic Systems: A Review

A large body of research has examined the behavioral and mental health consequences of polymorphisms in genes of the dopaminergic and serotonergic systems. Along with this, there has been considerable interest in the possibility that these polymorphisms have developed and/or been maintained due to the action of natural selection. Episodes of natural selection on a gene are expected to leave molecular “footprints” in the DNA sequences of the gene and adjacent genomic regions. Here we review the research literature investigating molecular signals of selection for genes of the dopaminergic and serotonergic systems. The gene SLC6A4, which codes for a serotonin transport protein, was the one gene for which there was consistent support from multiple studies for a selective episode. Positive selection on SLC6A4 appears to have been initiated ∼ 20–25,000 years ago in east Asia and possibly in Europe. There are scattered reports of molecular signals of selection for other neurotransmitter genes, but these have generally failed at replication across studies. In spite of speculation in the literature about selection on these genes, current evidence from population genomic analyses supports selectively neutral processes, such as genetic drift and population dynamics, as the principal drivers of recent evolution in dopaminergic and serotonergic genes other than SLC6A4.

Physical and verbal aggressive behavior and COMT genotype: Sensitivity to the environment

Catechol-O-methyltransferase (COMT) genotype has been implicated as a vulnerability factor for several psychiatric diseases as well as aggressive behavior, either directly, or in interaction with an adverse environment. The present study aimed at investigating the susceptibility properties of COMT genotype to adverse and favorable environment in relation to physical and verbal aggressive behavior. The COMT Val158Met polymorphism was genotyped in a Swedish population-based cohort including 1,783 individuals, ages 20-24 years (47% males). A significant three-way interaction was found, after correction for multiple testing, between COMT genotype, exposure to violence, and parent-child relationship in association with physical but not verbal aggressive behavior. Homozygous for the Val allele reported lower levels of physical aggressive behavior when they were exposed to violence and at the same time experienced a positive parent-child relationship compared to Met carriers. Thus, susceptibility properties of COMT genotype were observed in relation to physical aggressive behavior supporting the hypothesis that COMT genotypes are modifying the sensitivity to environment that confers either risk or protection for aggressive behavior. As these are novel findings, they warrant further investigation and replication in independent samples. © 2016 Wiley Periodicals, Inc.

Viele Wege führen zur Resilienz

Zusammenfassung. Die Popularität des Resilienzbegriffes in der Forschung und Praxis begünstigt, dass dieser Begriff uneinheitlich verwendet wird. Dabei wird in der Regel das Ergebnis einer gesunden Entwicklung trotz widriger Umstände mit den zugrunde liegenden Mechanismen und Prozessen der Gesunderhaltung konfundiert. Ausgehend von einem Verständnis von Resilienz als einem Label für eine gesunde Entwicklung trotz widriger Umstände werden drei mögliche Entwicklungsverläufe von Resilienz vorgestellt: (1) Resilienz durch Resistenz, (2) Resilienz durch Kompensation und (3) Resilienz durch Restrukturieren. Die Bedeutung der unterschiedlichen Verläufe für die Gestaltung von Resilienzförderprogrammen wird für unterschiedliche Zielgruppen diskutiert.

Child maltreatment, impulsivity, and antisocial behavior in African American children: Moderation effects from a cumulative dopaminergic gene index

A model examining the effects of an increasing number of maltreatment subtypes experienced on antisocial behavior, as mediated by impulsivity and moderated by a polygenic index of dopaminergic genotypes, was investigated. An African American sample of children (N = 1,012, M age = 10.07) with and without maltreatment histories participated. Indicators of aggression, delinquency, and disruptive peer behavior were obtained from peer- and counselor-rated measures to form a latent variable of antisocial behavior; impulsivity was assessed by counselor report. Five genotypes in four dopaminergic genes (dopamine receptors D4, D2, known as DRD4, DRD2; dopamine active transporter 1, known as DAT1; and catechol-O-methyltransferase, known as COMT) conferring heightened environmental sensitivity were combined into one polygenic index. Using structural equation modeling, a first-stage, moderated-mediation model was evaluated. Age and sex were entered as covariates, both as main effects and in interaction with maltreatment and the gene index. The model had excellent fit: χ2 (32, N = 1,012) = 86.51, p < .001; comparative fit index = 0.982, Tucker-Lewis index = 0.977, root mean square error of approximation = 0.041, and standardized root mean square residual = 0.022. The effect of maltreatment subtypes on antisocial behavior was partially mediated by impulsivity (β = 0.173, p < .001), and these relations were moderated by the number of differentiating dopaminergic genotypes. Specifically, a significant Gene × Environment interaction (β = 0.016, p = .013) indicated that the relation between maltreatment and impulsivity was stronger as children evinced more differentiating genotypes, thereby strengthening the mediational effect of impulsivity on antisocial behavior. These findings elucidate the manner by which maltreated children develop early signs of antisocial behavior, and the genetic mechanisms involved in greater vulnerability for maladaptation in impulse control within the context of child maltreatment.

Multilevel developmental approaches to understanding the effects of child maltreatment: Recent advances and future challenges

Recent research in the field of child maltreatment has begun to shed new light on the emergence of health problems in children by emphasizing the responsiveness of developmental processes to children's environmental and biological contexts. Here, I highlight recent trends in the field with an emphasis on the effects of early life stress across multiple levels of developmental domains.

Beyond risk: Prospective effects of GABA Receptor Subunit Alpha-2 (GABRA2) × Positive Peer Involvement on adolescent behavior

Research on Gene × Environment interactions typically focuses on maladaptive contexts and outcomes. However, the same genetic factors may also impact susceptibility to positive social contexts, leading to adaptive behavior. This paper examines whether the GABA receptor subunit alpha-2 (GABRA2) single nucleotide polymorphism rs279858 moderates the influence of positive peer affiliation on externalizing behavior and various forms of competence. Regions of significance were calculated to determine whether the form of the interaction supported differential susceptibility (increased sensitivity to both low and high positive peer affiliation) or vantage sensitivity (increased sensitivity to high positive peer affiliation). It was hypothesized that those carrying the homozygous minor allele (GG) would be more susceptible to peer effects. A sample (n = 300) of primarily male (69.7%) and White (93.0%) adolescents from the Michigan Longitudinal Study was assessed from ages 12 to 17. There was evidence for prospective Gene × Environment interactions in three of the four models. At low levels of positive peer involvement, those with the GG genotype were rated as having fewer adaptive outcomes, while at high levels they were rated as having greater adaptive outcomes. This supports differential susceptibility. Conceptualizing GABRA2 variants as purely risk factors may be inaccurate. Genetic differences in susceptibility to adaptive environmental exposures warrants further investigation.

Adolescent neurobiological susceptibility to social context

Adolescence has been characterized as a period of heightened sensitivity to social contexts. However, adolescents vary in how their social contexts affect them. According to neurobiological susceptibility models, endogenous, biological factors confer some individuals, relative to others, with greater susceptibility to environmental influences, whereby more susceptible individuals fare the best or worst of all individuals, depending on the environment encountered (e.g., high vs. low parental warmth). Until recently, research guided by these theoretical frameworks has not incorporated direct measures of brain structure or function to index this sensitivity. Drawing on prevailing models of adolescent neurodevelopment and a growing number of neuroimaging studies on the interrelations among social contexts, the brain, and developmental outcomes, we review research that supports the idea of adolescent neurobiological susceptibility to social context for understanding why and how adolescents differ in development and well-being. We propose that adolescent development is shaped by brain-based individual differences in sensitivity to social contexts - be they positive or negative - such as those created through relationships with parents/caregivers and peers. Ultimately, we recommend that future research measure brain function and structure to operationalize susceptibility factors that moderate the influence of social contexts on developmental outcomes.

Learning to trust: trust and attachment in early psychosis

BACKGROUND

Distrust and social dysfunction are characteristic in psychosis and may arise from attachment insecurity, which is elevated in the disorder. The relationship between trust and attachment in the early stages of psychosis is unknown, yet could help to understand interpersonal difficulties and disease progression. This study aimed to investigate whether trust is reduced in patients with early psychosis and whether this is accounted for by attachment avoidance and attachment anxiety.

METHOD

We used two trust games with a cooperative and unfair partner in a sample of 39 adolescents with early psychosis and 100 healthy controls.

RESULTS

Patients had higher levels of attachment anxiety, but the groups did not differ in attachment avoidance. Basic trust was lower in patients than controls, as indicated by lower initial investments. During cooperation patients increased their trust towards levels of controls, i.e. they were able to learn and to override initial suspiciousness. Patients decreased their trust less than controls during unfair interactions. Anxious attachment was associated with higher basic trust and higher trust during unfair interactions and predicted trust independent of group status. Discussion Patients showed decreased basic trust but were able to learn from the trustworthy behaviour of their counterpart. Worries about the acceptance by others and low self-esteem are associated with psychosis and attachment anxiety and may explain behaviour that is focused on conciliation, rather than self-protection.

Religion priming and an oxytocin receptor gene (OXTR) polymorphism interact to affect self-control in a social context

Using a genetic moderation approach, this study examines how an experimental prime of religion impacts self-control in a social context, and whether this effect differs depending on the genotype of an oxytocin receptor gene (OXTR) polymorphism (rs53576). People with different genotypes of OXTR seem to have different genetic orientations toward sociality, which may have consequences for the way they respond to religious cues in the environment. In order to determine whether the influence of religion priming on self-control is socially motivated, we examine whether this effect is stronger for people who have OXTR genotypes that should be linked to greater rather than less social sensitivity (i.e., GG vs. AA/AG genotypes). The results showed that experimentally priming religion increased self-control behaviors for people with GG genotypes more so than people with AA/AG genotypes. Furthermore, this Gene × Religion interaction emerged in a social context, when people were interacting face to face with another person. This research integrates genetic moderation and social psychological approaches to address a novel question about religion's influence on self-control behavior, which has implications for coping with distress and psychopathology. These findings also highlight the importance of the social context for understanding genetic moderation of psychological effects.

Early life adversity and serotonin transporter gene variation interact to affect DNA methylation of the corticotropin-releasing factor gene promoter region in the adult rat brain

The interaction between childhood maltreatment and the serotonin transporter (5-HTT) gene linked polymorphic region has been associated with increased risk to develop major depression. This Gene × Environment interaction has furthermore been linked with increased levels of anxiety and glucocorticoid release upon exposure to stress. Both endophenotypes are regulated by the neuropeptide corticotropin-releasing factor (CRF) or hormone, which is expressed by the paraventricular nucleus of the hypothalamus, the bed nucleus of the stria terminalis, and the central amygdala (CeA). Therefore, we hypothesized that altered regulation of the expression of CRF in these areas represents a major neurobiological mechanism underlying the interaction of early life stress and 5-HTT gene variation. The programming of gene transcription by Gene × Environment interactions has been proposed to involve epigenetic mechanisms such as DNA methylation. In this study, we report that early life stress and 5-HTT genotype interact to affect DNA methylation of the Crf gene promoter in the CeA of adult male rats. Furthermore, we found that DNA methylation of a specific site in the Crf promoter significantly correlated with CRF mRNA levels in the CeA. Moreover, CeA CRF mRNA levels correlated with stress coping behavior in a learned helplessness paradigm. Together, our findings warrant further investigation of the link of Crf promoter methylation and CRF expression in the CeA with behavioral changes that are relevant for psychopathology.

A differential susceptibility analysis reveals the "who and how" about adolescents' responses to preventive interventions: tests of first- and second-generation Gene × Intervention hypotheses

This study was designed to investigate a genetic moderation effect of dopamine receptor 4 gene (DRD4) alleles that have seven or more repeats (long alleles) on an intervention to deter drug use among rural African American adolescents in high-risk families. Adolescents (N = 291, M age = 17) were assigned randomly to the Adults in the Making (AIM) program or to a control condition and were followed for 27.5 months. Adolescents provided data on drug use and vulnerability cognitions three times after pretest. Pretest assessments of caregiver depressive symptoms, disruption in the home, and support toward the adolescent were used to construct a family risk index. Adolescents living in high-risk families who carried at least one DRD4 long allele and were assigned to the control condition evinced greater escalations in drug use than did (a) adolescents who lived in high-risk families, carried the DRD4 long allele, and were assigned to AIM, or (b) adolescents assigned to either condition who carried no DRD4 long alleles. AIM-induced reductions in vulnerability cognitions were responsible for the Family Risk × AIM × DRD4 status drug use prevention effects. These findings support differential susceptibility predictions and imply that prevention effects on genetically susceptible individuals may be underestimated.

Serotonin transporter linked polymorphic region (5-HTTLPR) genotype moderates the longitudinal impact of early caregiving on externalizing behavior

We examined caregiver report of externalizing behavior from 12 to 54 months of age in 102 children randomized to care as usual in institutions or to newly created high-quality foster care. At baseline no differences by group or genotype in externalizing were found. However, changes in externalizing from baseline to 42 months of age were moderated by the serotonin transporter linked polymorphic region genotype and intervention group, where the slope for short-short (S/S) individuals differed as a function of intervention group. The slope for individuals carrying the long allele did not significantly differ between groups. At 54 months of age, S/S children in the foster care group had the lowest levels of externalizing behavior, while children with the S/S genotype in the care as usual group demonstrated the highest rates of externalizing behavior. No intervention group differences were found in externalizing behavior among children who carried the long allele. These findings, within a randomized controlled trial of foster care compared to continued care as usual, indicate that the serotonin transporter linked polymorphic region genotype moderates the relation between early caregiving environments to predict externalizing behavior in children exposed to early institutional care in a manner most consistent with differential susceptibility.

Genetic differential susceptibility on trial: meta-analytic support from randomized controlled experiments

The most stringent test of differential susceptibility theory is provided by randomized control trials examining the moderating role of genetic markers of differential susceptibility in experimental manipulations of the environment (Gene × Experimental Environment interactions), being at least 10 times more powerful than correlational Gene × Environment interaction studies. We identified 22 experiments involving 3,257 participants with various developmental outcomes (e.g., externalizing problems, internalizing behaviors, and cognitive development). Effect sizes contrasting experimental versus control group were computed both for subjects with the polymorphism considered indicative of heightened susceptibility (e.g., the dopamine receptor D4 gene seven-repeat allele and the serotonin transporter polymorphic region short allele) and others expected to be low in susceptibility (e.g., the dopamine receptor D4 gene four-repeat allele and the serotonin transporter polymorphic region short allele). Clear-cut experimental support for genetic differential susceptibility emerged: the combined effect size of the interventions for the susceptible genotypes amounted to r = .33 (95% confidence interval = 0.23, 0.42; p < .01) versus a nonsignificant r = .08 (95% confidence interval = -0.02, 0.17; p = .12) for the hypothesized nonsusceptible genotypes. Macrotrials showed more evidence of genetic differential susceptibility than microtrials, and differential susceptibility was more clearly observed in trials with externalizing and cognitive outcomes than with internalizing problems. This meta-analysis shows proof of principle for genetic differential susceptibility and indicates that it is time to explore its mechanisms and limits. The concept of differential susceptibility alters the idea of constitutional "risk" factors (reactive temperament and risk genotypes), and points to intervention efficacy hidden in Gene × Environment interactions.

Depressive symptoms in adolescence: The role of perceived parental support, psychological control, and proactive control in interaction with 5-HTTLPR

BACKGROUND

Parenting dimensions are associated with depressive symptoms in adolescents. We investigated the role of perceived parenting dimensions and gene-environment interactions between these perceived parenting dimensions and five well-known variable number of tandem repeats (VNTRs): 5-HTTLPR, STin2, DAT1, DRD4, and MAO-A, in depressive symptoms.

METHODS

From a non-clinical sample of 1111 Belgian adolescents (mean age: 13.79 years, SD=.94; 51% boys), 1103 adolescents consented for genetic research. Five VNTRs were analyzed using DNA from saliva samples. Perceived parenting dimensions (i.e., support, proactive control, psychological control, punishment, and harsh punishment) were examined using self-report scales completed by adolescents and their parents. Depressive symptoms were investigated using the CES-D self-report scale. Statistical analyses were performed in R using linear regression.

RESULTS

Parental support, as perceived by the adolescent, was negatively associated with depressive symptoms (CES-D) and psychological control was positively associated with these symptoms. The only interaction effect withstanding correction for multiple testing was observed for 5-HTTLPR and the difference in proactive control as perceived by adolescents in comparison to parents. Short-allele carriers showed more depressive symptoms when there was a higher discrepancy in proactive control as perceived by adolescents versus parents.

CONCLUSIONS

Our results suggest that perceived parenting dimensions are associated with depressive symptoms, as measured by the CES-D. We only found modest evidence for 5-HTTLPR as a moderator in the association between the difference in perception of proactive control (adolescents vs. parents) and depressive symptoms.

Transactional Links Between Teacher-Student Relationships and Adolescent Rule-Breaking Behavior and Behavioral School Engagement: Moderating Role of a Dopaminergic Genetic Profile Score

Throughout adolescence, there is an increase in rule-breaking behavior and a decrease in behavioral school engagement. The role of teacher-student relationship quality in the development of these adjustment problems remains understudied. This study examined how adolescent-reported teacher-student affiliation and dissatisfaction and parent-reported rule-breaking behavior and behavioral engagement impact one another throughout adolescence. In addition, we examined the moderating effect of genes by means of a Biologically Informed Multilocus genetic Profile Score (BIMPS), a composite score reflecting the cumulative effect of multiple dopaminergic genes, with a higher score indicating higher dopamine signaling in the adolescent brain. We used three-year longitudinal data from 1111 adolescents (51 % boys; M age = 13.79), and their parents. Cross-lagged analyses revealed a transactional process in which adolescents who display more rule-breaking behavior and less behavioral engagement experienced increased subsequent dissatisfaction with their teachers, which in turn further increased their adjustment problems. Also, adolescents with more adjustment problems experienced decreased subsequent affiliation with their teachers. The other way around, adolescents' behavioral engagement also benefitted from positive relationships with teachers. Multi-group analyses revealed genetic moderation for behavioral engagement, but not for rule-breaking. Specifically, adolescents who had a BIMPS score coding for moderate levels of dopamine signaling (instead of high or low signaling) were most affected in their behavioral engagement when they experienced dissatisfaction with their teachers. Our study findings may guide schools in implementing interventions to create a supportive class and school environment including positive, supportive teacher-student relationships and indicate that providing a such a supportive school environment is important for all adolescents.

Teacher-student relationships and adolescent behavioral engagement and rule-breaking behavior: The moderating role of dopaminergic genes

This study examined whether the dopamine transporter DAT1 and the dopamine receptor DRD4 genes moderate the effect of student-reported teacher-student relationship affiliation or dissatisfaction on parent-reported adolescent rule-breaking behavior and behavioral engagement. The sample included 1053 adolescents (51% boys, Mage=13.79) from grades 7 to 9. Regression analyses were conducted using Mplus while controlling for multiple testing and nested data. Adolescents who experienced stronger affiliation with their teachers were more engaged in school, whereas greater dissatisfaction predicted more rule-breaking behavior. In addition, a significant gene-environment interaction was found for both genes examined. The link between low teacher-student affiliation and low engagement was more pronounced for DAT1-10R homozygotes. The link between high teacher-student dissatisfaction and more rule-breaking was stronger for DRD4 non-long carriers. Implications for understanding the role of teacher-student relationships in adolescence and suggestions for future research are outlined.

Dopaminergic variants in siblings at high risk for autism: Associations with initiating joint attention

Younger siblings of children with autism spectrum disorder (ASD; high-risk siblings) exhibit lower levels of initiating joint attention (IJA; sharing an object or experience with a social partner through gaze and/or gesture) than low-risk siblings of children without ASD. However, high-risk siblings also exhibit substantial variability in this domain. The neurotransmitter dopamine is linked to brain areas associated with reward, motivation, and attention, and common dopaminergic variants have been associated with attention difficulties. We examined whether these common dopaminergic variants, DRD4 and DRD2, explain variability in IJA in high-risk (n = 55) and low-risk (n = 38) siblings. IJA was assessed in the first year during a semi-structured interaction with an examiner. DRD4 and DRD2 genotypes were coded according to associated dopaminergic functioning to create a gene score, with higher scores indicating more genotypes associated with less efficient dopaminergic functioning. Higher dopamine gene scores (indicative of less efficient dopaminergic functioning) were associated with lower levels of IJA in the first year for high-risk siblings, while the opposite pattern emerged in low-risk siblings. Findings suggest differential susceptibility-IJA was differentially associated with dopaminergic functioning depending on familial ASD risk. Understanding genes linked to ASD-relevant behaviors in high-risk siblings will aid in early identification of children at greatest risk for difficulties in these behavioral domains, facilitating targeted prevention and intervention. Autism Res 2016, 9: 1142-1150. © 2016 International Society for Autism Research, Wiley Periodicals, Inc.