The Nonshared Environment in Adolescent Development (NEAD) project: a longitudinal family study of twins and siblings from adolescence to young adulthood

Explaining the influence of non-shared environment (NSE) on symptoms of behaviour problems from preschool to adulthood: mind the missing NSE gap

BACKGROUND

Individual differences in symptoms of behaviour problems in childhood and adolescence are not primarily due to nature or nurture - another substantial source of variance is non-shared environment (NSE). However, few specific environmental factors have been found to account for these NSE estimates. This creates a 'missing NSE' gap analogous to the 'missing heritability' gap, which refers to the shortfall in identifying DNA differences responsible for heritability. We assessed the extent to which variance in behaviour problem symptoms during the first two decades of life can be accounted for by measured NSE effects after controlling for genetics and shared environment.

METHODS

The sample included 4,039 pairs of twins in the Twins Early Development Study whose environments and symptoms of behaviour problems were assessed in preschool, childhood, adolescence and early adulthood via parent, teacher and self-reports. Twin-specific environments were assessed via parent-reports, including early life adversity, parental feelings, parental discipline and classroom environment. Multivariate longitudinal twin model-fitting was employed to estimate the variance in behaviour problem symptoms at each age that could be predicted by environmental measures at the previous age.

RESULTS

On average across childhood, adolescence and adulthood, parent-rated NSE composite measures accounted for 3.4% of the reliable NSE variance (1.0% of the total variance) in parent-rated, symptoms of behaviour problems, 0.5% (0.1%) in teacher-rated symptoms and 0.9% (0.5%) in self-rated symptoms after controlling for genetics, shared environment and error of measurement. Cumulatively across development, our parent-rated NSE measures in preschool, childhood and adolescence predicted 4.7% of the NSE variance (2.0% of the total variance) in parent-rated and 0.3% (0.2%) in self-rated behaviour problem symptoms in adulthood.

CONCLUSIONS

The missing NSE gap between variance explained by measured environments and total NSE variance is large. Home and classroom environments are more likely to influence behaviour problem symptoms via genetics than via NSE.

Intergenerational transmission of psychopathology: An examination of symptom severity and directionality

The present study examined the intergenerational transmission of internalizing and externalizing symptom severity, which indexes comorbidity, and symptom directionality, which indicates differentiation toward externalizing versus internalizing problems. Data are from 854 male and female, same-sex adult twin pairs born between 1926 and 1971 (32-60 years old, M = 44.9 years, SD = 4.9 years) from the Twin and Offspring Study in Sweden and their adolescent offspring (11-22 years old, M = 15.7 years, SD = 2.4 years, 52% female). Children-of-twins models revealed additive (9%) and dominant (45%) genetic and nonshared environmental (47%) influences on twins' symptom severity, and additive genetic (39%) and nonshared environmental (61%) influences on twins' symptom directionality. Both comorbid problems and preponderance of symptoms of a particular - internalizing versus externalizing - spectrum were correlated across parent and child generations, although associations were modest especially for directionality (i.e., transmission of specific symptom type). By interpreting findings alongside a recent study of adolescent twins, we demonstrate that the intergenerational transmission of symptom severity and symptom directionality are both unlikely to be attributable to genetic transmission, are both likely to be influenced by direct phenotypic transmission and/or nonpassive rGE, and the intergenerational transmission of symptom severity is also likely to be influenced by passive rGE.

Illuminating the origins of the intergenerational transmission of psychopathology with a novel genetically informed design

Although it is well known that parental depression is transmitted within families across generations, the etiology of this transmission remains unclear. Our goal was to develop a novel study design capable of explicitly examining the etiologic sources of intergenerational transmission. We specifically leveraged naturally-occurring variations in genetic relatedness between parents and their adolescent children in the 720 families participating in the Nonshared Environment in Adolescent Development (NEAD) study, 58.5% of which included a rearing stepparent (nearly always a stepfather). Results pointed squarely to the environmental transmission of psychopathology between fathers and children. Paternal depression was associated with adolescent depression and adolescent behavior problems (i.e., antisocial behavior, headstrong behavior, and attention problems) regardless of whether or not fathers and their children were genetically related. Moreover, these associations persisted to a subset of "blended" families in which the father was biologically related to one participating child but not to the other, and appeared to be mediated via father-child conflict. Such findings are not only fully consistent with the environmental transmission of psychopathology across generations, but also add to extant evidence that parent-child conflict is a robust and at least partially environmental predictor of adolescent psychopathology.

Generalist genes and specialist environments for adolescent internalizing and externalizing problems: A test of severity and directionality

The generalist genes specialist environment model, when applied to developmental psychopathology, predicts that genetic influences should explain variance that is shared across internalizing and externalizing problems, whereas environmental influences should explain variance that distinguishes the two overarching problem types. The present study is a direct test of this hypothesis, leveraging a sample of 708 twins and siblings (aged 10-18 years, 93% White) from the United States. Measures of severity of symptoms, regardless of type, and of directionality of symptoms - whether the adolescent tended to exhibit more externalizing or internalizing problems - were subjected to genetic (A), shared environmental (C), and nonshared environmental (E) (ACE) variance decompositions. As expected, severity of problems was under substantial genetic influence, but there were also significant shared and nonshared environmental influences. Contrary to the generalist genes specialist environment model, directionality of problem type was also under considerable genetic influence, with modest nonshared environmental influence. Findings corroborate existing evidence from other designs highlighting the role of familial influences (including generalist genes) in comorbidity of adolescent internalizing and externalizing problems, but suggest that the specialist environments hypothesis may not be the key factor in distinguishing problem type.

Twins and Causal Inference: Leveraging Nature's Experiment

In this review, we discuss how samples comprising monozygotic and dizygotic twin pairs can be used for the purpose of strengthening causal inference by controlling for shared influences on exposure and outcome. We begin by briefly introducing how twin data can be used to inform the biometric decomposition of population variance into genetic, shared environmental, and nonshared environmental influences. We then discuss how extensions to this model can be used to explore whether associations between exposure and outcome survive correction for shared etiology (common causes). We review several analytical approaches that can be applied to twin data for this purpose. These include multivariate structural equation models, cotwin control methods, direction of causation models (cross-sectional and longitudinal), and extended family designs used to assess intergenerational associations. We conclude by highlighting some of the limitations and considerations that researchers should be aware of when using twin data for the purposes of interrogating causal hypotheses.

The Social Relations Model for Count Data

Abstract. The social relations model (SRM) is typically used to identify sources of variance in interpersonal dispositions in families. Traditionally, it uses dyadic measurements that are obtained from a round-robin design, where each family member rates each other family member. Those dyadic measurements are mostly considered to be continuous, but we, however, will discuss how the SRM can be adapted to count dyadic measurements. Such SRM for count data can be formulated in the SEM-framework by viewing it as a confirmatory factor analysis (CFA), but it can also be defined in the multilevel framework. These two frameworks result in equivalent models of which the parameters can be estimated using maximum likelihood estimation or a Bayesian approach. We perform a simulation study to compare the performance of those two estimators. As an illustration, we consider intergenerational co-activity data from a block design and contrast family dynamics between non-divorced families and stepfamilies.

Did I Inherit My Moral Compass? Examining Socialization and Evocative Mechanisms for Virtuous Character Development

Virtuous character development in children is correlated with parenting behavior, but the role of genetic influences in this association has not been examined. Using a longitudinal twin/sibling study (N = 720; Time 1 (T1) Mage = 12-14 years, Time 3 (T3) Mage = 25-27 years), the current report examines associations among parental negativity/positivity and offspring responsibility during adolescence, and subsequent young adult conscientiousness. Findings indicate that associations among parental negativity and offspring virtuous character during adolescence and young adulthood are due primarily to heritable influences. In contrast, the association between concurrent parental positivity and adolescent responsibility was due primarily to heritable and shared environmental influences. These findings underscore the contributions of heritable influences to the associations between parenting and virtuous character that have previously been assumed to be only environmentally influenced, emphasizing the complexity of mechanisms involved in the development of virtuous character.

Individual and Sibling Characteristics: Parental Differential Treatment and Adolescent Externalizing Behaviors

Adolescents' reports of parental differential treatment have been linked to increased externalizing behaviors. The current study investigated whether adolescent self-esteem and sibling relationship characteristics (age-spacing and sibling relationship quality) moderated associations between parental differential treatment and later externalizing behavior. Data was gathered at two assessments from 708 sibling pairs (94% White; 51% male; same-gender pairs <4 years apart in age). Older/younger siblings were aged MAssessment1 = 13.5/12.1 and MAssessment2 = 16.2/14.7 years. We found that higher levels of maternal differential treatment predicted greater residualized gains in externalizing behavior among older siblings who were (a) the same age as their sibling or near-to and had low self-esteem or (b) three years older than their sibling and had higher self-esteem. Higher levels of paternal differential treatment predicted greater residual gains in externalizing for older siblings with wider age ranges (regardless of self-esteem), and among older siblings with high levels of self-esteem (regardless of age difference). Surprisingly, maternal differential treatment was protective in one case: for adolescents with low self-esteem who were at least three years older than their siblings, maternal differential treatment predicted reduced externalizing behaviors. Paternal differential treatment was protective for more youth than maternal differential treatment: older siblings with low self-esteem who experienced paternal differential treatment exhibited decreased externalizing behaviors across adolescence, regardless of age difference. The findings highlight the importance of self-esteem and sibling age-spacing as particularly salient contextual influences in older siblings' perceptions of maternal and paternal differential treatment, and that maternal and especially paternal differential treatment does not always serve as a risk factor for externalizing problems.

Adolescent age moderates genetic and environmental influences on parent-adolescent positivity and negativity: Implications for genotype-environment correlation

We examined how genotype-environment correlation processes differ as a function of adolescent age. We tested whether adolescent age moderates genetic and environmental influences on positivity and negativity in mother-adolescent and father-adolescent relationships using parallel samples of twin parents from the Twin and Offspring Study in Sweden and twin/sibling adolescents from the Nonshared Environment in Adolescent Development Study. We inferred differences in the role of passive and nonpassive genotype-environment correlation based on biometric moderation findings. The findings indicated that nonpassive gene-environment correlation played a stronger role for positivity in mother- and father-adolescent relationships in families with older adolescents than in families with younger adolescents, and that passive gene-environment correlation played a stronger role for positivity in the mother-adolescent relationship in families with younger adolescents than in families with older adolescents. Implications of these findings for the timing and targeting of interventions on family relationships are discussed.

Translational Epidemiologic Approaches to Understanding the Consequences of Early-Life Exposures

Prominent developmental theories posit a causal link between early-life exposures and later functioning. Yet, observed associations with early exposures may not reflect causal effects because of genetic and environmental confounding. The current manuscript describes how a systematic series of epidemiologic analyses that combine several genetically-informative designs and statistical approaches can help distinguish between competing theories. In particular, the manuscript details how combining the use of measured covariates with sibling-comparisons, cousin-comparisons, and additional designs can help elucidate the sources of covariation between early-life exposures and later outcomes, including the roles of (a) factors that are not shared in families, including a potential causal effect of the exposure; (b) carryover effects from the exposure of one child to the next; and (c) familial confounding. We also describe key assumptions and how they can be critically evaluated. Furthermore, we outline how subsequent analyses, including effect decomposition with respect to measured, plausible mediators, and quantitative genetic models can help further specify the underlying processes that account for the associations between early-life exposures and offspring outcomes.

Parental knowledge is an environmental influence on adolescent externalizing

BACKGROUND

There is evidence both that parental monitoring is an environmental influence serving to diminish adolescent externalizing problems and that this association may be driven by adolescents' characteristics via genetic and/or environmental mechanisms, such that adolescents with fewer problems tell their parents more, and therefore appear to be better monitored. Without information on how parents' and children's genes and environments influence correlated parent and child behaviors, it is impossible to clarify the mechanisms underlying this association.

METHOD

The present study used the Extended Children of Twins model to distinguish types of gene-environment correlation and direct environmental effects underlying associations between parental knowledge and adolescent (age 11-22 years) externalizing behavior with a Swedish sample of 909 twin parents and their adolescent offspring and a US-based sample of 405 White adolescent siblings and their parents.

RESULTS

Results suggest that more parental knowledge is associated with less adolescent externalizing via a direct environmental influence independent of any genetic influences. There was no evidence of a child-driven explanation of the association between parental knowledge and adolescent externalizing problems.

CONCLUSIONS

In this sample of adolescents, parental knowledge exerted an environmental influence on adolescent externalizing after accounting for genetic influences of parents and adolescents. Because the association between parenting and child development originates in the parent, treatment for adolescent externalizing must not only include parents but should also focus on altering their parental style. Thus, findings suggest that teaching parents better knowledge-related monitoring strategies is likely to help reduce externalizing problems in adolescents.

Moderating the covariance between family member's substance use behavior

Twin and family studies implicitly assume that the covariation between family members remains constant across differences in age between the members of the family. However, age-specificity in gene expression for shared environmental factors could generate higher correlations between family members who are more similar in age. Cohort effects (cohort × genotype or cohort × common environment) could have the same effects, and both potentially reduce effect sizes estimated in genome-wide association studies where the subjects are heterogeneous in age. In this paper we describe a model in which the covariance between twins and non-twin siblings is moderated as a function of age difference. We describe the details of the model and simulate data using a variety of different parameter values to demonstrate that model fitting returns unbiased parameter estimates. Power analyses are then conducted to estimate the sample sizes required to detect the effects of moderation in a design of twins and siblings. Finally, the model is applied to data on cigarette smoking. We find that (1) the model effectively recovers the simulated parameters, (2) the power is relatively low and therefore requires large sample sizes before small to moderate effect sizes can be found reliably, and (3) the genetic covariance between siblings for smoking behavior decays very rapidly. Result 3 implies that, e.g., genome-wide studies of smoking behavior that use individuals assessed at different ages, or belonging to different birth-year cohorts may have had substantially reduced power to detect effects of genotype on cigarette use. It also implies that significant special twin environmental effects can be explained by age-moderation in some cases. This effect likely contributes to the missing heritability paradox.

Gene-environment correlation underlying the association between parental negativity and adolescent externalizing problems

Studies of adolescent or parent-based twins suggest that gene-environment correlation (rGE) is an important mechanism underlying parent-adolescent relationships. However, information on how parents' and children's genes and environments influence correlated parent and child behaviors is needed to distinguish types of rGE. The present study used the novel Extended Children of Twins model to distinguish types of rGE underlying associations between negative parenting and adolescent (age 11-22 years) externalizing problems with a Swedish sample of 909 twin parents and their adolescent offspring and a U.S.-based sample of 405 adolescent siblings and their parents. Results suggest that evocative rGE, not passive rGE or direct environmental effects of parenting on adolescent externalizing, explains associations between maternal and paternal negativity and adolescent externalizing problems.

Overview of Behavioral Genetics Research for Family Researchers

This article provides an overview of the methods, assumptions, and key findings of behavioral genetics methodology for family researchers with a limited background. We discuss how family researchers can utilize and contribute to the behavioral genetics field, particularly in terms of conducting research that seeks to explain shared environmental effects. This can be done, in part, by theoretically controlling for genetic confounds in research that seeks to determine cause-and-effect relationships among family variables and individual outcomes. Gene-environment correlation and interaction are especially promising areas for the family researcher to address. Given the methodological advancements in the field, we also briefly comment on new methods in molecular genetics for studying psychological mental health disorders.

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.

The Beijing Twin Study (BeTwiSt): a longitudinal study of child and adolescent development

Rates of emotional and behavioral problems among children and adolescents in China are increasing and represent a major public health concern. To investigate the etiology of such problems, including the effects and interplay of genes and environment, the Beijing Twin Study (BeTwiSt) was established. A representative sample of adolescent twins in Beijing (N = 1,387 pairs of adolescent twins, mostly between the ages of 10 and 18 years) was recruited and assessed longitudinally. Data collection included the following: emotional and behavioral problems (e.g., depressive symptoms, anxiety, delinquency, drinking, and smoking); family, peer, and school environments; stress; social and academic competence; cognitive traits (e.g., emotion suppression, rumination, and effortful control); and saliva samples for DNA genotyping and sequencing. The combination of quantitative and molecular genetic approaches and the timeliness of the project, with the sample residing in a region with a rapidly changing economic and cultural climate, are particular strengths of this study. Findings from this study are expected to help understanding of the etiological mechanisms underlying child and adolescent normal and abnormal development in regions undergoing substantial social, cultural, and economic changes.

Genetic and environmental influences on the association between pubertal maturation and internalizing symptoms

The literature consistently shows an association between pubertal maturation and internalizing problems in girls. The association for boys is less clear. The present study examines genetic and environmental influences on the association between pubertal maturation and internalizing problems for boys and girls in two primarily Caucasian adolescent twin/sibling studies: The Swedish Twin study of CHild and Adolescent Development (706 same-sex twin pairs aged 13-14, M = 13.7 years, 50 % female), and the Nonshared Environment in Adolescent Development sample (US-based, 687 same-sex twin/sibling pairs aged 10-18, M = 13.6 years, 47 % female). For girls, more advanced pubertal maturation was associated modestly with more internalizing problems, and that association was entirely explained by shared environmental influences. For boys, the association between pubertal maturation and internalizing problems was weak and inconsistent. Results for girls were remarkably consistent across samples. Findings suggest that nongenetic mechanisms mediate the association between pubertal maturation and internalizing problems. Findings have implications for intervention such that environmental influences shared by twins/siblings may provide the best targets for intervention strategies designed to minimize the potential negative effects of pubertal maturation on internalizing symptoms in girls.

Observed externalizing behavior: a developmental comparison of genetic and environmental influences across three samples

Estimates of genetic and environmental influences on externalizing behavior are markedly inconsistent. In an attempt to refine and extend our knowledge of externalizing behavior, the current study examined the etiology of externalizing behavior using observational data in middle childhood and adolescence from three twin and sibling samples. Observational ratings offer a unique perspective on externalizing behavior rarely examined within behavioral genetic designs. Shared environmental influences were significant and moderate to large in magnitude across all three samples (i.e., 44, 77, and 38%), while genetic influences (31%) were significant only for the adolescent sample. All three samples showed greater shared environmental influences and less genetic influence than is typically found when examining self-, parent-, and teacher-reports of externalizing behavior. These findings are consistent with other reports that have found evidence for shared environmental influences on measures of child externalizing behavior-in direct contrast to a commonly held perception that shared environmental factors do not have significant influences on behavior beyond early childhood.

The association between parent-child conflict and adolescent conduct problems over time: results from a longitudinal adoption study

A handful of prior adoption studies have confirmed that the cross-sectional relationship between child conduct problems and parent-child conflict at least partially originates in the shared environment. However, as the direction of causation between parenting and delinquency remains unclear, this relationship could be better explained by the adolescent's propensity to elicit conflictive parenting, a phenomenon referred to as an evocative gene-environment correlation. In the current study, the authors thus examined the prospective relationship between conduct problems and parent-child conflict in a sample of adoptive families. Participants included 672 adolescents in 405 adoptive families assessed at 2 time points roughly 4 years apart. Results indicated that parent-child conflict predicts the development of conduct problems, whereas conduct problems do not predict increases in parent-child conflict. Such findings suggest that evocative gene-environment correlations are highly unlikely to be an explanation of prior shared environmental effects during adolescence. Moreover, because the adolescents in this study do not share genes with their adoptive parents, the association between conduct problems and parent-child conflict is indicative of shared environmental mediation in particular. Implications of the findings are discussed.

The genetics of mood disorders

Studying the genetics of mood disorders has never been more exciting. We have moved rapidly from establishing the genetic basis of depression to asking questions about how genes are expressed. This has been made possible by the capacity to collect and sequence DNA for large samples cheaply. But "multidisciplinary" approaches investigating interrelationships between risk factors have also been increasingly adopted, encouraging collaborations between those studying genes and those studying the brain, cognition, and/or the social environment. In this review, we first describe findings from quantitative and molecular studies investigating the genetic basis of depression. Second, we present overviews of three hot topics of genetic research: gene-environment interplay, which considers how genetic factors shape exposure and responses toward the social environment; endophenotypic research, which identifies neurophysiological and psychological mediators of genetic risk; and epigenetics, which explain how early environments can foster changes in gene expression, altering subsequent emotional development.

Environmental contributions to the stability of antisocial behavior over time: are they shared or non-shared?

It has recently been argued that shared environmental influences are moderate, identifiable, and persistent sources of individual differences in most forms of child and adolescent psychopathology, including antisocial behavior. Unfortunately, prior studies examining the stability of shared environmental influences over time were limited by possible passive gene-environment correlations, shared informants effects, and/or common experiences of trauma. The current study sought to address each of these limitations. We examined adolescent self-reported antisocial behavior in a 3.5 year longitudinal sample of 610 biological and adoptive sibling pairs from the Sibling Interaction and Behavior Study (SIBS). Results revealed that 74-81% of shared environmental influences present at time 1 were also present at time 2, whereas most non-shared environmental influences (88-89%) were specific to a particular assessment period. Such results provide an important constructive replication of prior research, strongly suggesting that shared environmental contributions to antisocial behavior are systematic in nature.

Temperament and character associated with depressive symptoms in women: analysis of two genetically informative samples

Although previous research has explored associations between personality and depressive symptoms, a limited number of studies have assessed the extent to which genetic and environmental influences explain the association. This study investigated how temperament and character were associated with depressive symptoms in 131 pairs of twin and sibling women in early adulthood, as well as 326 pairs of twin women in middle adulthood. Results indicated that genetic influences accounted for a moderate to substantial percentage of the association between these personality features and depressive symptoms, emphasizing the role of genetic influences. Nonshared environmental influences made important contributions to the association between character and depressive symptoms, particularly in the sample of middle-aged twin women. These findings suggest that unique social experiences and relationships with a partner in adulthood may play an important role in these associations between character and depressive symptoms.

Aggressive versus nonaggressive antisocial behavior: distinctive etiological moderation by age

Research has supported the existence of distinct behavioral patterns, demographic correlates, and etiologic mechanisms for aggressive (AGG) versus nonaggressive but delinquent (DEL) antisocial behavior. Though behavioral genetic studies have the potential to further crystallize these dimensions, inconsistent results have limited their contribution. These inconsistencies may stem in part from the limited attention paid to the impact of age. In the current study, the authors thus examined age-related etiological moderation of AGG and DEL antisocial behavior in a sample of 720 sibling pairs (ranging in age from 10 to 18 years) with varying degrees of genetic relatedness. Results reveal that the magnitude of genetic and environmental influences on AGG remained stable across adolescence. By contrast, genetic influences on DEL increased dramatically with age, whereas shared environmental influences decreased. Subsequent longitudinal analyses fully replicated these results. Such findings highlight etiological distinctions between aggression and delinquency, and offer insights into the expression of genetic influences during development.

Aggressive behavior between siblings and the development of externalizing problems: evidence from a genetically sensitive study

This study investigated the prospective links between sibling aggression and the development of externalizing problems using a multilevel modeling approach with a genetically sensitive design. The sample consisted of 780 adolescents (390 sibling pairs) who participated in 2 waves of the Nonshared Environment in Adolescent Development project. Sibling pairs with varying degree of genetic relatedness, including monozygotic twins, dizygotic twins, full siblings, half siblings, and genetically unrelated siblings, were included. The results showed that sibling aggression at Time 1 was significantly associated with the focal child's externalizing problems at Time 2 after accounting for the intraclass correlations between siblings. Sibling aggression remained significant in predicting subsequent externalizing problems even after controlling for the levels of preexisting externalizing problems and mothers' punitive parenting. This pattern of results was fairly robust across models with different informants. The findings provide converging evidence for the unique contribution of sibling aggression in understanding changes in externalizing problems during adolescence.

Parental Divorce and Children's Adjustment

This article reviews the research literature on links between parental divorce and children's short-term and long-term adjustment. First, I consider evidence regarding how divorce relates to children's externalizing behaviors, internalizing problems, academic achievement, and social relationships. Second, I examine timing of the divorce, demographic characteristics, children's adjustment prior to the divorce, and stigmatization as moderators of the links between divorce and children's adjustment. Third, I examine income, interparental conflict, parenting, and parents well-being as mediators of relations between divorce and children's adjustment. Fourth, I note the caveats and limitations of the research literature. Finally, I consider notable policies related to grounds for divorce, child support, and child custody in light of how they might affect children s adjustment to their parents divorce.

An adoption study of parental depression as an environmental liability for adolescent depression and childhood disruptive disorders

OBJECTIVE

The authors used an adoption study design to investigate environmental influences on risk for psychopathology in adolescents with depressed parents.

METHOD

Participants were 568 adopted adolescents ascertained through large adoption agencies, 416 nonadopted adolescents ascertained through birth records, and their parents. Clinical interviews with parents and adolescents were used to determine lifetime DSM-IV-TR diagnoses of major depressive disorder, oppositional defiant disorder, conduct disorder, attention deficit hyperactivity disorder (ADHD), and substance use disorders in adolescents and major depression in mothers and fathers. Effects of parental depression (either parent with major depression, maternal major depression, and paternal major depression) on adolescent psychopathology were tested in nonadopted and adopted adolescents separately, and interactive effects of parental depression and adoption status were tested.

RESULTS

Either parent having major depression and a mother having major depression were associated with a significantly greater risk for major depression and disruptive behavior disorders in both nonadopted and adopted adolescents. Paternal depression did not have a main effect on any psychiatric disorder in adolescents and, with one exception (ADHD in adopted adolescents), did not predict significantly greater likelihoods of disorders in either nonadopted or adopted adolescents.

CONCLUSIONS

Maternal depression was an environmental liability for lifetime diagnoses of major depression and disruptive disorders in adolescents. Paternal depression was not associated with an increased risk for psychopathology in adolescents.