Marital conflict and conduct problems in Children of Twins

Parenting in the Context of the Child: Genetic and Social Processes

The focus on the role of parenting in child development has a long-standing history. When measures of parenting precede changes in child development, researchers typically infer a causal role of parenting practices and attitudes on child development. However, this research is usually conducted with parents raising their own biological offspring. Such research designs cannot account for the effects of genes that are common to parents and children, nor for genetically influenced traits in children that influence how they are parented and how parenting affects them. The aim of this monograph is to provide a clearer view of parenting by synthesizing findings from the Early Growth and Development Study (EGDS). EGDS is a longitudinal study of adopted children, their birth parents, and their rearing parents studied across infancy and childhood. Families (N = 561) were recruited in the United States through adoption agencies between 2000 and 2010. Data collection began when adoptees were 9 months old (males = 57.2%; White 54.5%, Black 13.2%, Hispanic/Latinx 13.4%, Multiracial 17.8%, other 1.1%). The median child age at adoption placement was 2 days (M = 5.58, SD = 11.32). Adoptive parents were predominantly in their 30s, White, and coming from upper-middle- or upper-class backgrounds with high educational attainment (a mode at 4-year college or graduate degree). Most adoptive parents were heterosexual couples, and were married at the beginning of the project. The birth parent sample was more racially and ethnically diverse, but the majority (70%) were White. At the beginning of the study, most birth mothers and fathers were in their 20s, with a mode of educational attainment at high school degree, and few of them were married. We have been following these family members over time, assessing their genetic influences, prenatal environment, rearing environment, and child development. Controlling for effects of genes common to parents and children, we confirmed some previously reported associations between parenting, parent psychopathology, and marital adjustment in relation to child problematic and prosocial behavior. We also observed effects of children's heritable characteristics, characteristics thought to be transmitted from parent to child by genetic means, on their parents and how those effects contributed to subsequent child development. For example, we found that genetically influenced child impulsivity and social withdrawal both elicited harsh parenting, whereas a genetically influenced sunny disposition elicited parental warmth. We found numerous instances of children's genetically influenced characteristics that enhanced positive parental influences on child development or that protected them from harsh parenting. Integrating our findings, we propose a new, genetically informed process model of parenting. We posit that parents implicitly or explicitly detect genetically influenced liabilities and assets in their children. We also suggest future research into factors such as marital adjustment, that favor parents responding with appropriate protection or enhancement. Our findings illustrate a productive use of genetic information in prevention research: helping parents respond effectively to a profile of child strengths and challenges rather than using genetic information simply to identify some children unresponsive to current preventive interventions.

Investigating the association between family connectedness and self-control in adolescence in a genetically sensitive design

Family connectedness is key for the development of self-control in early and middle childhood. But is family connectedness still important during the transitional phase of adolescence, when adolescents demand more independence from their parents and rely more on their peers? The aim of the present study was to investigate the association between family connectedness and self-control, and whether it still holds in adolescence using a genetically sensitive design. Data were used from a large sample of twins aged 14 (N = 11,260) and aged 16 (N = 8175), all enrolled in the Netherlands Twin Register. We applied bivariate twin models and monozygotic twin difference models to investigate the association between family connectedness and self-control and to unravel to what extent genetic and environmental factors explain this association. The results showed that more family connectedness is significantly related to better self-control in adolescence, albeit with a small effect size. Twin analyses revealed that this association was mainly explained by common genetic factors and that the effects of environmental factors were small. The current findings confirm the role of family connectedness in adolescent self-control. Importantly, however, the results demonstrate that phenomena we see within families seem the product of parent and children sharing the same genes rather than being exclusively attributable to environmental processes.

Like Father, like Child: Early Life Family Adversity and Children's Bullying Behaviors in Elementary School

Family adversity has been associated with children’s bullying behaviors. The evidence is, however, dominated by mothers’ perceptions of the family environment and a focus on mothers’ behaviors. This prospective population-based study examined whether children’s bullying behaviors were associated with mother- and father-reported family adversity, assessed before and after child birth. Peer-nominations were used to assess bullying behaviors of 1298 children in elementary school (mean age 7.5 years). The following paternal risk factors were prospectively associated with children’s bullying behaviors: (1) father-reported prenatal family distress, (2) fathers’ hostility at preschool age, and (3) fathers’ harsh disciplinary practices at preschool age, but effect sizes were relatively small. The effect of maternal risk factors was less consistent, only mother-reported family distress in childhood was associated with children’s bullying behaviors. The associations were independent of background family risk factors (i.e., life stress, contextual factors, and other background factors such as parental education and risk taking record) and early childhood externalizing problems. Moreover, our results indicated that father-reported family adversity predicted children’s bullying behaviors over and above the background family risk factors, early childhood externalizing problems and mother-reported family adversity. We also demonstrated that the association of fathers’ prenatal hostility and family distress with subsequent bullying behavior of their child at school was partly mediated by fathers’ harsh disciplinary practices at preschool age. Our findings highlight the importance of fathers’ behaviors in the development of children’s bullying behaviors.

Paternal Antisocial Behavior (But Not Paternal ADHD) Is Associated With Negative Parenting and Child Conduct Problems

OBJECTIVE

Parental psychopathology and parenting quality robustly predict negative outcomes among children with ADHD. Little research has investigated associations between paternal ADHD symptoms and parenting, though there is clear evidence linking maternal ADHD symptoms with both suboptimal parenting and child conduct problems, and considerable research supporting fathers' significant contributions to their children's development.

METHOD

This cross-sectional study examined psychopathology and parenting in a sample of fathers ( N = 102) and their 5- to 12-year-old children with previously diagnosed ADHD.

RESULTS

Results suggested that paternal antisocial personality disorder (ASPD) symptoms (rather than ADHD symptoms) were robustly associated with child conduct problems, with an indirect effect through paternal negative parenting.

CONCLUSION

This study suggests that negative parenting may be a potential mechanism by which paternal ASPD is associated with child conduct problems, and demonstrates the importance of considering co-occurring psychopathology in research examining adult ADHD, parenting, and child outcomes.

Children's appraisals of interparental conflict predict event-related potential components

Interparental conflict and neural correlates of children's emotion processing were examined. Event-related potential (ERP) data were collected from 87 children (9-11 years old) with stimuli depicting interpersonal anger, happiness, and neutrality. Three ERP components were modulated by child-reported measures of conflict, reflecting a progression from early sensory attention to cognitive control to stimulus categorization. Negative conflict predicted larger N1 and N2 amplitudes on happy than on angry trials. Greater self-blame for conflict predicted larger N2 amplitudes across emotions and larger P3 amplitudes on angry than on neutral or happy trials. Results suggest conflict-related experiences shape processing of interpersonal emotion.

The role of parental marital discord in the etiology of externalizing problems during childhood and adolescence

Previous research has established that parental marital discord is associated with higher levels of offspring externalizing behaviors, but it is unclear how parental relationship functioning is associated with the genetic and environmental variance on a factor of externalizing problems. Thus, the current study assessed how parental marital discord moderates genetic and environmental variance on offspring externalizing problems at two different ages: childhood and late adolescence. That is, the magnitude of genetic and environmental influences on offspring externalizing at ages 11 and 17 was examined as a function of parental marital discord. Consistent with a diathesis-stress model of psychopathology, it was hypothesized that with increasing marital discord, genetic influences on externalizing would be more pronounced. Rather, results indicated that for the 11-year-old sample, nonshared environmental influences were greater when parental marital discord was low, and comparatively, shared environmental influences contributed more to the variance in externalizing problems when parental marital discord was high. No moderation was found for the 17-year-old cohort. In contrast to studies that do not find an effect of the shared environment, these results provide evidence that the common rearing environment has an impact on externalizing problems in preadolescent children.

Transactional cascades of destructive interparental conflict, children's emotional insecurity, and psychological problems across childhood and adolescence

This study examined the transactional interplay among dimensions of destructive interparental conflict (i.e., hostility and dysphoria), children's emotional insecurity, and their psychological problems from middle childhood and adolescence. Participants were 232 families, with the first of five measurement occasions occurring when children were in first grade (M age = 7 years). Cross-lagged, autoregressive models were conducted with a multiple-method, multiple-informant measurement approach to identify developmental cascades of interparental and child cascades. Results indicated that emotional insecurity was a particularly powerful mediator of prospective associations between interparental conflict (i.e., dysphoria and hostility) and child adjustment during adolescence rather than childhood. In reflecting bidirectionality in relationships between interparental and child functioning, children's psychological problems predicted increases in interparental dysphoria during childhood and adolescence. Although emotional insecurity was not identified as a proximal predictor of interparental difficulties, an indirect cascade was identified whereby insecurity in early adolescence was associated with increases in teen psychological problems, which in turn predicted greater interparental dysphoria over time. Results are interpreted in the context of how they advance transactional formulation of emotional security theory and its resulting translational implications for clinical initiatives.

Socio-emotionally significant experience and children's processing of irrelevant auditory stimuli

Theory and research indicate considerable influence of socio-emotionally significant experiences on children's functioning and adaptation. In the current study, we examined neurophysiological correlates of children's allocation of information processing resources to socio-emotionally significant events, specifically, simulated marital interactions. We presented 9- to 11-year-old children (n=24; 11 females) with 15 videos of interactions between two actors posing as a married couple. Task-irrelevant brief auditory probes were presented during the videos, and event-related potentials (ERPs) elicited to the auditory probes were measured. As hypothesized, exposure to higher levels of interparental conflict was associated with smaller P1, P2, and N2 ERPs to the probes. This finding is consistent with the idea that children who had been exposed to more interparental conflict attended more to the videos and diverted fewer cognitive resources to processing the probes, thereby producing smaller ERPs to the probes. In addition, smaller N2s were associated with more child behavior problems, suggesting that allocating fewer processing resources to the probes was associated with more problem behavior. Results are discussed in terms of implications of socio-emotionally significant experiences for children's processing of interpersonal interactions.

The Socioeconomic Pathways Leading to Romantic Relationship Outcomes: A Genetically Informed Early Life Course Investigation

The present study tests a multilevel comprehensive model incorporating both life course processes and genetic influences leading to young adults' romantic relationship quality using data from 1,560 adolescents over 13 years in the nationally representative Add Health sample. Results provided evidence of a socioeconomic mediating pathway linking early family and community contexts to young adults' romantic relationship quality, and novel evidence for both direct and interactive genetic associations that relate to these mediating pathways. A cumulative genetic index showed (a) direct associations with young adults' socioeconomic attainment and (b) interactions with community adversity and mothers' marital stability on young adults' achieved socioeconomic context and relationship quality.

Gene-Environment Interplay in the Context of Romantic Relationships

A growing body of research supports an important role for genetic factors on intimate, romantic relationships. In this article, we review research that has examined the interplay between genetic and environmental influences on romantic relationships and the associations between relationship outcomes and important individual differences related to relationships. We first elaborate on how behavioral genetic and molecular genetic methods can be used to understand the etiology of relationship outcomes. We then review empirical studies that have examined gene-environment correlations and gene-by-environment interactions in predicting romantic relationship outcomes (e.g., relationship formation, relationship quality and functioning, relationship dissolution) and their association with the physical health, mental health, and well-being of relationship partners.

A Sex-Positive Framework for Research on Adolescent Sexuality

In this article, I propose a sex-positive framework for research on adolescent sexuality in which I consider consensual sexual activities in adolescence as developmentally normative and potentially healthy. The sex-positive framework is contrasted with the predominant "risk" perspective that presumes that abstinence from sexual activity is the ideal behavioral outcome for teenagers. Evidence from longitudinal and behavioral genetic studies indicates that engaging in sexual intercourse in adolescence does not typically cause worse psychological functioning. The relationship context of sexual experience may be a critical moderator of its psychological impact. Moreover, cross-cultural data on adolescents' contraception usage, unintended pregnancy, and sexually transmitted infections suggest that, despite the unacceptably high rate of negative health consequences among U.S. teenagers, adolescents can have the developmental capacity to regulate the health risks inherent in sexual activity. Understanding adolescent sexuality can be fostered by considering sexual well-being, a multidimensional construct that incorporates an adolescent's sexual self-efficacy, sexual self-esteem, feelings of sexual pleasure and satisfaction, and freedom from pain and negative affect regarding sexuality. New research is necessary to understand the development of adolescent sexual well-being, including its normative age trends, its reciprocal links with sexual behavior, and its impact on psychological and physical health.

Identifying the “truly disadvantaged”

There has been significant interest in examining the developmental factors that predispose individuals to chronic criminal offending. This body of research has identified some social-environmental risk factors as potentially important. At the same time, the research producing these results has generally failed to employ genetically sensitive research designs, thereby potentially generating biased parameter estimates. The current study addresses this gap in the literature by using both a standard social science methodology (SSSM) and two separate genetically informative research designs to examine whether parent, teacher, and peer risk factors are associated with four maladaptive outcomes: arrests, low IQ, reduced self-control, and a combined measure of the “truly disadvantaged.” Analysis of twin pairs drawn from the National Longitudinal Study of Adolescent to Adult Health revealed that the SSSMs produced upwardly biased estimates of the impact of social-environmental influences on each of the four outcomes. Once genetic factors were controlled, the effect of social-environmental risk was reduced (but remained significant in certain cases). We conclude by discussing these findings in the context of criminal justice policy and their implications for future criminological research.

The quality of the interparental relationship does not moderate the etiology of child conduct problems

BACKGROUND

Although there is a clear phenotypic relationship between the quality of the interparental or marital relationship and child conduct problems (CP), the etiology of this association is as yet unclear. One possibility is that this association takes the form of a genotype-environment interaction (G × E), whereby the quality of the interparental relationship acts to moderate the etiology of child CP. The current study sought to evaluate this possibility.

METHOD

We examined multiple measures and informant reports of the quality of the interparental relationship in a sample of more than 700 child twin families from the Michigan State University Twin Registry (MSUTR). Analyses consisted of a series of latent G × E models.

RESULTS

The 'no moderation' model provided the best fit to the data in nearly all cases, findings that collectively provide strong evidence against the possibility that the etiology of CP is moderated by the quality of the interparental relationship.

CONCLUSIONS

Our findings suggest that, contrary to implicit (and sometimes explicit) assumptions in the field, it is not the case that every environmental risk (or protective) factor exacerbates (or suppresses) genetic influences on CP. Future research should seek to delineate the specific environmental experiences that do serve as etiologic moderators of CP, and to clarify how this G × E interplay might change over the course of development.

Effects of adverse early-life events on aggression and anti-social behaviours in animals and humans

We review the impact of early adversities on the development of violence and antisocial behaviour in humans, and present three aetiological animal models of escalated rodent aggression, each disentangling the consequences of one particular adverse early-life factor. A review of the human data, as well as those obtained with the animal models of repeated maternal separation, post-weaning social isolation and peripubertal stress, clearly shows that adverse developmental conditions strongly affect aggressive behaviour displayed in adulthood, the emotional responses to social challenges and the neuronal mechanisms activated by conflict. Although similarities between models are evident, important differences were also noted, demonstrating that the behavioural, emotional and neuronal consequences of early adversities are to a large extent dependent on aetiological factors. These findings support recent theories on human aggression, which suggest that particular developmental trajectories lead to specific forms of aggressive behaviour and brain dysfunctions. However, dissecting the roles of particular aetiological factors in humans is difficult because these occur in various combinations; in addition, the neuroscientific tools employed in humans still lack the depth of analysis of those used in animal research. We suggest that the analytical approach of the rodent models presented here may be successfully used to complement human findings and to develop integrative models of the complex relationship between early adversity, brain development and aggressive behaviour.

Understanding the relative contributions of direct environmental effects and passive genotype-environment correlations in the association between familial risk factors and child disruptive behavior disorders

BACKGROUND

Previous work reports an association between familial risk factors stemming from parental characteristics and offspring disruptive behavior disorders (DBDs). This association may reflect (a) the direct effects of familial environment and (b) a passive gene-environment correlation (r(GE)), wherein the parents provide both the genes and the environment. The current study examined the contributions of direct environmental influences and passive r(GE) by comparing the effects of familial risk factors on child DBDs in genetically related (biological) and non-related (adoptive) families.

METHOD

Participants were 402 adoptive and 204 biological families. Familial environment was defined as maternal and paternal maladaptive parenting and antisociality, marital conflict and divorce; offspring DBDs included attention deficit hyperactivity disorder (ADHD), conduct disorder (CD) and oppositional defiant disorder (ODD). Mixed-level regressions estimated the main effects of familial environment, adoption status and the familial environment by adoption status interaction term, which tested for the presence of passive r(GE).

RESULTS

There was a main effect of maternal and paternal maladaptive parenting and marital discord on child DBDs, indicating a direct environmental effect. There was no direct environmental effect of maternal or paternal antisociality, but maternal and paternal antisociality had stronger associations with child DBDs in biological families than adoptive families, indicating the presence of a passive r(GE).

CONCLUSIONS

Many familial risk factors affected children equally across genetically related and non-related families, providing evidence for direct environmental effects. The relationship of parental antisociality and offspring DBDs was best explained by a passive r(GE), where a general vulnerability toward externalizing psychopathology is passed down by the parents to the children.

Behavioral Genetic Approaches and Family Theory

Family theories have been founded on research that cannot discriminate genetic and environmental influences and, consequently, most theories do not have highly developed models of gene-environment interplay in families. Behavioral genetic approaches, which can identify gene-environment interplay, have typically not been driven by family theories and have lacked adequate measurement of family processes. In this article, the authors describe behavioral genetic mechanisms and methods using representative examples of research on family processes, highlighting the advantages of an integrated approach. New directions in research and theory driven by an integrated approach are discussed.

Etiological contributions to the covariation between children's perceptions of inter-parental conflict and child behavioral problems

Prior work has suggested that inter-parental conflict likely plays an etiological role in child behavior problems. However, family-level measurement of inter-parental conflict in most traditional child twin studies has made it difficult to tease apart the specific causal mechanisms underlying this association. The Children's Perception of Inter-parental Conflict scale (CPIC) provides a child-specific measurement tool for examining these questions, as its subscales tap multiple dimensions of conflict assessed from the child's (rather than the parent's) perspective. The current study examined (1) the degree of genetic and environmental influence on each of the CPIC subscales, and (2) etiological contributions to the covariation between the CPIC scales and parental reports of child behavioral problems. The CPIC was completed by 1,200 child twins (aged 6-11 years) from the Michigan State University Twin Registry (MSUTR). Parents completed the Child Behavior Checklist (CBCL) to assess child internalizing and externalizing behavior problems. Multivariate models were examined to evaluate the relative contributions of genetic and environmental factors to both the CPIC scales and to their overlap with child behavioral outcomes. Modeling results indicated no significant moderation of sex or age. Significant environmental overlap emerged between the CPIC conflict properties scale and child internalizing and externalizing problems. By contrast, significant genetic correlations emerged between the CPIC self-blame scale and externalizing problems as well as between the CPIC threat scale and internalizing problems. Overall, findings suggest that the subscales of the CPIC are somewhat etiologically diverse and may provide a useful tool for future investigations of possible gene-environment interplay.

Four factors for the initiation of substance use by young adulthood: a 10-year follow-up twin and sibling study of marital conflict, monitoring, siblings, and peers

This study examined genetic and environmental influences on associations among marital conflict about the child, parental monitoring, sibling relationship negativity, and peer delinquency during adolescence and initiation of illegal drug use by young adulthood. The sample comprised data collected longitudinally from same-sex sibling pairs and parents when the siblings were 10-18 years old (M = 14.5 and 12.9 years for Child 1 and Child 2, respectively) and 20-35 years old (M = 26.8 and 25.5 years for Child 1 and Child 2, respectively). Findings indicate four factors that explain the initiation of illegal drug use: two shaped by genetic influences and two shaped by environments shared by siblings. The two genetically shaped factors probably have distinct mechanisms: one a child-initiated coercive process in the family and the other parent and peer processes shaped by the child's disclosure. The environmentally influenced factors seem distinctively shaped by poor parental monitoring of both sibs and the effects of siblings on each other's deviancy.

Accounting for the physical and mental health benefits of entry into marriage: a genetically informed study of selection and causation

Married adults show better psychological adjustment and physical health than their separated/divorced or never-married counterparts. However, this apparent "marriage benefit" may be due to social selection, social causation, or both processes. Genetically informed research designs offer critical advantages for helping to disentangle selection from causation by controlling for measured and unmeasured genetic and shared environmental selection. Using young-adult twin and sibling pairs from the National Longitudinal Study of Adolescent Health (Harris, 2009), we conducted genetically informed analyses of the association between entry into marriage, cohabitation, or singlehood and multiple indices of psychological and physical health. The relation between physical health and marriage was completely explained by nonrandom selection. For internalizing behaviors, selection did not fully explain the benefits of marriage or cohabitation relative to being single, whereas for externalizing symptoms, marriage predicted benefits over cohabitation. The genetically informed approach provides perhaps the strongest nonexperimental evidence that these observed effects are causal.

Pathways and processes of risk in associations among maternal antisocial personality symptoms, interparental aggression, and preschooler's psychopathology

Two studies examined the nature and processes underlying the joint role of interparental aggression and maternal antisocial personality as predictors of children's disruptive behavior problems. Participants for both studies included a high-risk sample of 201 mothers and their 2-year-old children in a longitudinal, multimethod design. Addressing the form of the interplay between interparental aggression and maternal antisocial personality as risk factors for concurrent and prospective levels of child disruptive problems, the Study 1 findings indicated that maternal antisocial personality was a predictor of the initial levels of preschooler's disruptive problems independent of the effects of interparental violence, comorbid forms of maternal psychopathology, and socioeconomic factors. In attesting to the salience of interparental aggression in the lives of young children, latent difference score analyses further revealed that interparental aggression mediated the link between maternal antisocial personality and subsequent changes in child disruptive problems over a 1-year period. To identify the family mechanisms that account for the two forms of intergenerational transmission of disruptive problems identified in Study 1, Study 2 explored the role of children's difficult temperament, emotional reactivity to interparental conflict, adrenocortical reactivity in a challenging parent-child task, and experiences with maternal parenting as mediating processes. Analyses identified child emotional reactivity to conflict and maternal unresponsiveness as mediators in pathways between interparental aggression and preschooler's disruptive problems. The findings further supported the role of blunted adrenocortical reactivity as an allostatic mediator of the associations between parental unresponsiveness and child disruptive problems.

Offspring ADHD as a risk factor for parental marital problems: controls for genetic and environmental confounds

BACKGROUND

Previous studies have found that child attention-deficit/hyperactivity disorder (ADHD) is associated with more parental marital problems. However, the reasons for this association are unclear. The association might be due to genetic or environmental confounds that contribute to both marital problems and ADHD.

METHOD

Data were drawn from the Australian Twin Registry, including 1,296 individual twins, their spouses, and offspring. We studied adult twins who were discordant for offspring ADHD.Using a discordant twin pairs design, we examined the extent to which genetic and environmental confounds,as well as measured parental and offspring characteristics, explain the ADHD-marital problems association.

RESULTS

Offspring ADHD predicted parental divorce and marital conflict. The associations were also robust when comparing differentially exposed identical twins to control for unmeasured genetic and environmental factors, when controlling for measured maternal and paternal psychopathology,when restricting the sample based on timing of parental divorce and ADHD onset, and when controlling for other forms of offspring psychopathology. Each of these controls rules out alternative explanations for the association.

CONCLUSION

The results of the current study converge with those of prior research in suggesting that factors directly associated with offspring ADHD increase parental marital problems.

Toward greater specificity in identifying associations among interparental aggression, child emotional reactivity to conflict, and child problems

This study examined specific forms of emotional reactivity to conflict and temperamental emotionality as explanatory mechanisms in pathways among interparental aggression and child psychological problems. Participants of the multimethod, longitudinal study included 201 two-year-old children and their mothers who had experienced elevated violence in the home. Consistent with emotional security theory, autoregressive structural equation model analyses indicated that children's fearful reactivity to conflict was the only consistent mediator in the associations among interparental aggression and their internalizing and externalizing symptoms 1year later. Pathways remained significant across maternal and observer ratings of children's symptoms and with the inclusion of other predictors and mediators, including children's sad and angry forms of reactivity to conflict, temperamental emotionality, gender, and socioeconomic status.

From correlates to causes: can quasi-experimental studies and statistical innovations bring us closer to identifying the causes of antisocial behavior?

Longitudinal, epidemiological studies have identified robust risk factors for youth antisocial behavior, including harsh and coercive discipline, maltreatment, smoking during pregnancy, divorce, teen parenthood, peer deviance, parental psychopathology, and social disadvantage. Nevertheless, because this literature is largely based on observational studies, it remains unclear whether these risk factors have truly causal effects. Identifying causal risk factors for antisocial behavior would be informative for intervention efforts and for studies that test whether individuals are differentially susceptible to risk exposures. In this article, we identify the challenges to causal inference posed by observational studies and describe quasi-experimental methods and statistical innovations that may move researchers beyond discussions of risk factors to allow for stronger causal inference. We then review studies that used these methods, and we evaluate whether robust risk factors identified from observational studies are likely to play a causal role in the emergence and development of youth antisocial behavior. There is evidence of causal effects for most of the risk factors we review. However, these effects are typically smaller than those reported in observational studies, suggesting that familial confounding, social selection, and misidentification might also explain some of the association between risk exposures and antisocial behavior. For some risk factors (e.g., smoking during pregnancy, parent alcohol problems), the evidence is weak that they have environmentally mediated effects on youth antisocial behavior. We discuss the implications of these findings for intervention efforts to reduce antisocial behavior and for basic research on the etiology and course of antisocial behavior.

A genetically informed study of associations between family functioning and child psychosocial adjustment

Research has documented associations between family functioning and offspring psychosocial adjustment, but questions remain regarding whether these associations are partly due to confounding genetic factors and other environmental factors. The current study used a genetically informed approach, the Children of Twins design, to explore the associations between family functioning (family conflict, marital quality, and agreement about parenting) and offspring psychopathology. Participants were 867 twin pairs (388 monozygotic; 479 dizygotic) from the Twin and Offspring Study in Sweden, their spouses, and children (51.7% female; M = 15.75 years). The results suggested associations between exposure to family conflict (assessed by the mother, father, and child) and child adjustment were independent of genetic factors and other environmental factors. However, when family conflict was assessed using only children's reports, the results indicated that genetic factors also influenced these associations. In addition, the analyses indicated that exposure to low marital quality and agreement about parenting was associated with children's internalizing and externalizing problems and that genetic factors also contributed to the associations of marital quality and agreement about parenting with offspring externalizing problems.

Trajectories of parenting and child negative emotionality during infancy and toddlerhood: a longitudinal analysis

The current longitudinal study examined trajectories of child negative emotionality, parenting efficacy, and overreactive parenting among 382 adoptive families during infancy and toddlerhood. Data were collected from adoptive parents when the children were 9-, 18-, and 27-month-old. Latent growth curve modeling indicated age-related increases in child negative emotionality and overreactive parenting for adoptive fathers and adoptive mothers (AM), and decreases in parent efficacy among AM. Increases in child negative emotionality were also associated with increases in parent overreactivity and decreases in maternal efficacy. Mothers' and fathers' developmental patterns were linked within but not across parenting domains. Limitations and directions for future research are discussed.

Gene - Environment Interplay, Family Relationships, and Child Adjustment

This paper reviews behavioral genetic research from the past decade that has moved beyond simply studying the independent influences of genes and environments. The studies considered in this review have instead focused on understanding gene - environment interplay, including genotype - environment correlation ( rGE) and genotype × environment interaction (G × E). Studies have suggested that rGE is an important pathway through which family relationships are associated with child adjustment. Also important are direct causal influences of family relationships on child adjustment, independent of genetic confounds. Other studies have indicated that genetic and environmental influences on child adjustment are moderated by different levels of family relationships in G × E interactions. Genetically informed studies that have examined family relations have been critical to advancing our understanding of gene - environment interplay.

Parental depression and offspring psychopathology: a children of twins study

BACKGROUND

Associations between parental depression and offspring affective and disruptive disorders are well documented. Few genetically informed studies have explored the processes underlying intergenerational associations.

METHOD

A semi-structured interview assessing DSM-III-R psychiatric disorders was administered to twins (n=1296) from the Australian Twin Register (ATR), their spouses (n=1046) and offspring (n=2555). We used the Children of Twins (CoT) design to delineate the extent to which intergenerational associations were consistent with a causal influence or due to genetic confounds.

RESULTS

In between-family analyses, parental depression was associated significantly with offspring depression [hazard ratio (HR) 1.52, 95% confidence interval (CI) 1.20-1.93] and conduct disorder (CD; HR 2.27, CI 1.31-3.93). Survival analysis indicated that the intergenerational transmission of depression is consistent with a causal (environmental) inference, with a significant intergenerational association in offspring of discordant monozygotic (MZ) twin pairs (HR 1.39, CI 1.00-1.94). Logistic regression analysis suggested that the parental depression-offspring CD association was due to shared genetic liability in the parents and offspring. No intergenerational association was found when comparing the offspring of discordant MZ twins [odds ratio (OR) 1.41, CI 0.63-3.14], but offspring of discordant dizygotic (DZ) twins differed in their rates of CD (OR 2.53, CI 0.95-6.76). All findings remained after controlling for several measured covariates, including history of depression and CD in the twins' spouses.

CONCLUSIONS

The mechanisms underlying associations between parental depression and offspring psychopathology seem to differ depending on the outcome. The results are consistent with a causal environmental role of parental depression in offspring depression whereas common genetic factors account for the association of parental depression and offspring CD.

Genetic Thinking in the Study of Social Relationships: Five Points of Entry

For nearly a generation, researchers studying human behavioral development have combined genetically informed research designs with careful measures of social relationships such as parenting, sibling relationships, peer relationships, marital processes, social class stratifications, and patterns of social engagement in the elderly. In what way have these genetically informed studies altered the construction and testing of social theories of human development? We consider five points of entry where genetic thinking is taking hold. First, genetic findings suggest an alternative scenario for explaining social data. Associations between measures of the social environment and human development may be due to genes that influence both. Second, genetic studies add to other prompts to study the early developmental origins of current social phenomena in midlife and beyond. Third, genetic analyses promise to shed light on understudied social systems, such as sibling relationships, that have an impact on human development independent of genotype. Fourth, genetic analyses anchor in neurobiology individual differences in resilience and sensitivity to both adverse and favorable social environments. Finally, genetic analyses increase the utility of laboratory simulations of human social processes and of animal models.

Aggressive behavior, related conduct problems, and variation in genes affecting dopamine turnover

A number of dopamine-related genes have been implicated in the etiology of violent behavior and conduct problems. Of these genes, the ones that code for the enzymes that influence the turnover of dopamine (DA) have received the most attention. In this study, we investigated 12 genetic polymorphisms in four genes involved with DA functioning (COMT, MAOA and MAOB, and DbetaH) in 179 incarcerated male Russian adolescents and two groups of matched controls: boys without criminal records referred to by their teachers as (a) "troubled-behavior-free" boys, n=182; and (b) "troubled-behavior" boys, n=60. The participants were classified as (1) being incarcerated or not, (2) having the DSM-IV diagnosis of conduct disorder (CD) or not, and (3) having committed violent or nonviolent crimes (for the incarcerated individuals only). The findings indicate that, although no single genetic variant in any of the four genes differentiated individuals in the investigated groups, various linear combinations (i.e., haplotypes) and nonlinear combinations (i.e., interactions between variants within and across genes) of genetic variants resulted in informative and robust classifications for two of the three groupings. These combinations of genetic variants differentiated individuals in incarceration vs. nonincarcerated and CD vs. no-CD groups; no informative combinations were established consistently for the grouping by crime within the incarcerated individuals. This study underscores the importance of considering multiple rather than single markers within candidate genes and their additive and interactive combinations, both with themselves and with nongenetic indicators, while attempting to understand the genetic background of such complex behaviors as serious conduct problems.

Associations between father absence and age of first sexual intercourse

Children raised without a biological father in the household have earlier average ages of first sexual intercourse than children raised in father-present households. Competing theoretical perspectives have attributed this either to effects of father absence on socialization and physical maturation or to nonrandom selection of children predisposed for early sexual intercourse into father-absent households. Genetically informative analyses of the children of sister dyads (N = 1,382, aged 14-21 years) support the selection hypothesis: This association seems attributable to confounded risks, most likely genetic in origin, which correlated both with likelihood of father absence and early sexual behavior. This holds implications for environmental theories of maturation and suggests that previous research may have inadvertently overestimated the role of family structure in reproductive maturation.

Children's patterns of emotional reactivity to conflict as explanatory mechanisms in links between interpartner aggression and child physiological functioning

BACKGROUND

This paper examined children's fearful, sad, and angry reactivity to interparental conflict as mediators of associations between their exposure to interparental aggression and physiological functioning.

METHODS

Participants included 200 toddlers and their mothers. Assessments of interparental aggression and children's emotional reactivity were derived from maternal surveys and a semi-structured interview. Cortisol levels and cardiac indices of sympathetic nervous system (SNS) and parasympathetic nervous system (PNS) activity were used to assess toddler physiological functioning.

RESULTS

Results indicated that toddler exposure to interparental aggression was associated with greater cortisol levels and PNS activity and diminished SNS activity. Toddler angry emotional reactivity mediated associations between interparental aggression and cortisol and PNS functioning. Fearful emotional reactivity was a mediator of the link between interparental aggression and SNS functioning.

CONCLUSIONS

The results are interpreted within conceptualizations of how exposure and reactivity to family risk organize individual differences in physiological functioning.

Emotion dysregulation in the intergenerational transmission of romantic relationship conflict

The role of emotion dysregulation in the intergenerational transmission of romantic relationship conflict was examined using multimethod and multiagent prospective longitudinal data across 21 years for 190 men and their mothers and fathers. As predicted, an individual's emotion dysregulation was a key mediator in the transmission of relationship conflict, along with poor parenting skills. Parents' emotion dysregulation was directly related to their son's emotion dysregulation, which was in turn associated with the son's later relationship conflict. Additionally, parents' emotion dysregulation was significantly related to their poor discipline skills, which were linked to the son's emotion dysregulation and eventual relationship conflict. Findings highlight emotion dysregulation as a significant mechanism explaining the continuity of romantic relationship conflict across generations.

The relationship between interparental conflict and adolescents’ affective well-being: Mediation of cognitive appraisals and moderation of peer status

This study examined the mediation effect of cognitive appraisals and the moderation role of peer status in the association between interparental conflict and adolescents’ affective well-being based on a sample of 549 Chinese adolescents from 7th to 12th grades. Interparental conflict properties, adolescents’ cognitive appraisals of conflict, affective well-being, and peer status were measured through scales and peer nomination surveys. The results of structure equation modeling showed that: cognitive appraisals totally mediated the association between marital conflict and adolescents’ affective well-being; peer status moderated the effect of marital conflict on adolescents’ positive affect but not on negative affect; and the relationship between marital conflict and positive affect showed different patterns for adolescents of different social status. Therefore, to better understand affective well-being of adolescents from high marital conflict families, their cognitive appraisals of conflict and peer relations should be taken into account.

Parental divorce and adolescent delinquency: ruling out the impact of common genes

Although the well-documented association between parental divorce and adolescent delinquency is generally assumed to be environmental (i.e., causal) in origin, genetic mediation is also possible. Namely, the behavior problems often found in children of divorce could derive from similar pathology in the parents, pathology that is both heritable and increases the risk that the parent will experience divorce. To test these alternative hypotheses, the authors made use of a novel design that incorporated timing of divorce in a sample of 610 adoptive and biological families. They reasoned that if genes common to parent and child mediate this association, nonadopted youth should manifest increased delinquency in the presence of parental divorce even if the divorce preceded their birth (i.e., was from a prior parental relationship). However, should the association be environmental in origin, the authors reasoned that adolescents should manifest increased delinquency only in response to divorce exposure, and this association should not vary by adoption status. Results firmly supported the latter, suggesting that it is the experience of parental divorce, and not common genes, that drives the association between divorce and adolescent delinquency.

Searching for an environmental effect of parental alcoholism on offspring alcohol use disorder: a genetically informed study of children of alcoholics

The children-of-twins design was used to isolate a potentially causal environmental impact of having an alcoholic parent on offspring alcohol use disorder, by an examination of whether the children of alcoholics were at a higher risk for alcohol use disorders than were the children of nonalcoholic parents, even after correlated familial factors were controlled. Participants were 1,224 male and female twins from 836 twin pairs selected from the Australian Twin Registry, 2,334 of the twins' 18-39-year-old offspring, and 983 spouses of the twins. Lifetime histories of Diagnostic and Statistical Manual of Mental Disorders (4th ed.) alcohol use disorders were obtained by structured, psychiatric, telephone interviews conducted individually with each of the family members. Comparisons of the offspring of twins who were discordant for alcoholism indicated that there was no longer a statistically significant difference between the children of alcoholics and the children of nonalcoholics after genetic and family environmental factors correlated with having an alcoholic parent were controlled. The results of this study suggest that the direct causal effect of being exposed to an alcoholic parent on offspring alcohol use disorder is modest at best.

The cross-generational mother-daughter-aunt-niece design: establishing validity of the MDAN design with NLSY fertility variables

Using National Longitudinal Survey of Youth (NLSY) fertility variables, we introduce and illustrate a new genetically-informative design. First, we develop a kinship linking algorithm, using the NLSY79 and the NLSY-Children data to link mothers to daughters and aunts to nieces. Then we construct mother-daughter correlations to compare to aunt-niece correlations, an MDAN design, within the context of the quantitative genetic model. The results of our empirical illustration, which uses DF Analysis and generalized estimation equations (GEE) to estimate biometrical parameters from NLSY79 sister-sister pairs and their children in the NLSY-Children dataset, provide both face validity and concurrent validity in support of the efficacy of the design. We describe extensions of the MDAN design. Compared to the typical within-generational design used in most behavior genetic research, the cross-generational feature of this design has certain advantages and interesting features. In particular, we note that the equal environment assumption of the traditional biometrical model shifts in the context of a cross-generational design. These shifts raise questions and provide motivation for future research using the MDAN and other cross-generational designs.

Quantitative genetic studies of antisocial behaviour

This paper will broadly review the currently available twin and adoption data on antisocial behaviour (AB). It is argued that quantitative genetic research can make a significant contribution to further the understanding of how AB develops. Genetically informative study designs are particularly useful for investigating several important questions such as whether: the heritability estimates vary as a function of assessment method or gender; the relative importance of genetic and environmental influences varies for different types of AB; the environmental risk factors are truly environmental; and genetic vulnerability influences susceptibility to environmental risk. While the current data are not yet directly translatable for prevention and treatment programmes, quantitative genetic research has concrete translational potential. Quantitative genetic research can supplement neuroscience research in informing about different subtypes of AB, such as AB coupled with callous-unemotional traits. Quantitative genetic research is also important in advancing the understanding of the mechanisms by which environmental risk operates.

Smoking during pregnancy and offspring externalizing problems: an exploration of genetic and environmental confounds

Previous studies have documented that smoking during pregnancy (SDP) is associated with offspring externalizing problems, even when measured covariates were used to control for possible confounds. However, the association may be because of nonmeasured environmental and genetic factors that increase risk for offspring externalizing problems. The current project used the National Longitudinal Survey of Youth and their children, ages 4-10 years, to explore the relations between SDP and offspring conduct problems (CPs), oppositional defiant problems (ODPs), and attention-deficit/hyperactivity problems (ADHPs) using methodological and statistical controls for confounds. When offspring were compared to their own siblings who differed in their exposure to prenatal nicotine, there was no effect of SDP on offspring CP and ODP. This suggests that SDP does not have a causal effect on offspring CP and ODP. There was a small association between SDP and ADHP, consistent with a causal effect of SDP, but the magnitude of the association was greatly reduced by methodological and statistical controls. Genetically informed analyses suggest that unmeasured environmental variables influencing both SDP and offspring externalizing behaviors account for the previously observed associations. That is, the current analyses imply that important unidentified environmental factors account for the association between SDP and offspring externalizing problems, not teratogenic effects of SDP.

Prospective associations from family-of-origin interactions to adult marital interactions and relationship adjustment

To test the social learning-based hypothesis that marital conflict resolution patterns are learned in the family of origin, longitudinal, observational data were used to assess prospective associations between family conflict interaction patterns during adolescence and offspring's later marital conflict interaction patterns. At age 14 years, 47 participants completed an observed family conflict resolution task with their parents. In a subsequent assessment 17 years later, the participants completed measures of marital adjustment and an observed marital conflict interaction task with their spouse. As predicted, levels of hostility and positive engagement expressed by parents and adolescents during family interactions were prospectively linked with levels of hostility and positive engagement expressed by offspring and their spouses during marital interactions. Family-of-origin hostility was a particularly robust predictor of marital interaction behaviors; it predicted later marital hostility and negatively predicted positive engagement, controlling for psychopathology and family-of-origin positive engagement. For men, family-of-origin hostility also predicted poorer marital adjustment, an effect that was mediated through hostility in marital interactions. These findings suggest a long-lasting influence of family communication patterns, particularly hostility, on offspring's intimate communication and relationship functioning.

A behavior genetic investigation of adolescent motherhood and offspring mental health problems

The present study examines the relations between adolescent motherhood and children's behavior, substance use, and internalizing problems in a sample of 1,368 children of 712 female twins from Australia. Adolescent motherhood remained significantly associated with all mental health problems, even when using a quasiexperimental design capable of controlling for genetic and environmental confounds. However, the relation between adolescent motherhood and offspring behavior problems and substance use was partially confounded by family background variables that influence both generations. The results are consistent with a causal relation between adolescent motherhood and offspring mental health problems, and they highlight the usefulness of behavior genetic designs when examining putative environmental risks for the development of psychopathology. The generalizability of these results to the United States, which has a higher adolescent birth rate, is discussed.

A Genetically Informed Study of the Intergenerational Transmission of Marital Instability

Environmental or genetic influences, or both could account for the increased risk of divorce among the offspring of separated parents. Previous studies have used covariates to statistically control for confounds, but the present research is the first genetically informed study of the topic. The investigation used the Children of Twins Design with twins, their spouses, and their young adult offspring (n = 2,310) from the Australian Twin Registry to test whether selection on the basis of genetic or shared environment factors accounted for part of the inter-generational association. The analyses also controlled for measured characteristics of both parents. The results suggest that both environmentally mediated and genetic risk account for the intergenerational transmission, supporting the roles of both selection and causation.

Intergenerational transmission of childhood conduct problems: a Children of Twins Study

CONTEXT

The familial nature of childhood conduct problems has been well documented, but few genetically informed studies have explicitly explored the processes through which parental conduct problems influence an offspring's behavior problems.

OBJECTIVE

To delineate the genetic and environmental processes underlying the intergenerational transmission of childhood conduct problems.

DESIGN

We used hierarchical linear models to analyze data from a Children of Twins Study, a quasiexperimental design, to explore the extent to which genetic factors common to both generations, unmeasured environmental factors that are shared by twins, or measured characteristics of both parents confound the intergenerational association.

SETTING

Participants were recruited from the community and completed a semistructured diagnostic telephone interview.

PARTICIPANTS

The research used a high-risk sample of twins, their spouses, and their young adult offspring (n = 2554) from 889 twin families in the Australian Twin Registry, but the analyses used sample weights to produce parameter estimates for the community-based volunteer sample of twins. Main Outcome Measure Number of conduct disorder symptoms.

RESULTS

The magnitude of the intergenerational transmission was significant for all offspring, though it was stronger for males (effect size [Cohen d] = 0.21; 95% confidence interval, 0.15-0.17) than females (d = 0.09; 95% confidence interval, 0.05-0.14). The use of the Children of Twins design and measured covariates indicated that the intergenerational transmission of conduct problems for male offspring was largely mediated by environmental variables specifically related to parental conduct disorder (d = 0.13; 95% confidence interval, 0.02-0.23). In contrast, the intergenerational transmission of conduct problems was not because of environmentally mediated causal processes for female offspring (d = - 0.09; 95% confidence interval, - 0.20 to 0.03); a common genetic liability accounted for the intergenerational relations.

CONCLUSIONS

The mechanisms underlying the intergenerational transmission of conduct problems depend on the sex of the offspring. The results are consistent with an environmentally mediated causal role of parental conduct problems on behavior problems in males. Common genetic risk, however, confounds the entire intergenerational transmission in female offspring.