Sex differences in the genetic and environmental influences on childhood conduct disorder and adult antisocial behavior.

Sex differences in the genetic and environmental influences on childhood conduct disorder and adult antisocial behavior were examined in a large community sample of 6,383 adult male, female, and opposite-sex twins. Retrospective reports of childhood conduct disorder (prior to 18 years of age) were obtained when participants were approximately 30 years old, and lifetime reports of adult antisocial behavior (antisocial behavior after 17 years of age) were obtained 8 years later. Results revealed that either the genetic or the shared environmental factors influencing childhood conduct disorder differed for males and females (i.e., a qualitative sex difference), but by adulthood, these sex-specific influences on antisocial behavior were no longer apparent. Further, genetic and environmental influences accounted for proportionally the same amount of variance in antisocial behavior for males and females in childhood and adulthood (i.e., there were no quantitative sex differences). Additionally, the stability of antisocial behavior from childhood to adulthood was slightly greater for males than females. Though familial factors accounted for more of the stability of antisocial behavior for males than females, genetic factors accounted for the majority of the covariation between childhood conduct disorder and adult antisocial behavior for both sexes. The genetic influences on adult antisocial behavior overlapped completely with the genetic influences on childhood conduct disorder for both males and females. Implications for future twin and molecular genetic studies are discussed. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Problem behavior in early and middle childhood: an initial behavior genetic analysis

Twin samples were used to estimate the relative importance of genetic and environmental influences on problem behavior in children, assessed by the Child Behavior Checklist (CBCL). For the younger cohort, mothers completed the CBCL/2-3, while for the older cohort the CBCL/4-18 was used. Nearly half of the older sample had also been assessed with the questionnaire for younger children at a prior date, providing tentative answers regarding continuity and change in the etiology of problem behavior. Results suggested that shared environmental influences may be more important in early childhood than in middle childhood, while the reverse holds for genetic influences.     

Genetic and environmental influences on interpersonal cognitions and associations with depressive symptoms in 8-year-old twins.

Less is known about depression in children than in adults. This study integrates fields by combining cognitive and interpersonal research investigating childhood depression symptoms through the use of a genetic framework. Three research questions are addressed. First, what are the associations among interpersonal cognitions, anxiety, and depression? Second, what are the relative magnitudes of genetic and environmental influences on interpersonal cognitions? Third, to what extent do genetic and environmental influences explain associations between interpersonal cognitions and depression? Three hundred pairs of 8-year-old twins reported on symptoms of depression and anxiety by completing the Children's Depression Inventory and the Screen for Childhood Anxiety-Related Emotional Disorders. The authors examined interpersonal cognitions with the Children's Expectation of Social Behaviors and the Perceptions of Peers and Self Questionnaires. Interpersonal cognitions were more strongly correlated with depression (mean r = .35) than with anxiety (mean r = .13). Genetic influence on interpersonal cognitions was small (M = 3%), and associations between interpersonal cognitions and depression were mainly explained by environmental influences. These latter findings may result from interpersonal cognitions in young children, reflecting life experiences as opposed to trait-like cognitive biases. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Developmental structure of genetic influences on antisocial behavior across childhood and adolescence.

It is necessary to determine if causal influences on developing antisocial behavior change with age to guide both research and theory on its origins. The extent to which the same genetic factors influence antisocial behavior across 4–17 years of age was estimated using 2,482 sibling pairs of varying genetic relatedness. Assessments of antisocial behavior by mothers (4–9 years), mothers and youth (10–13 years), and youth (14–17 years) reflected the changing validity of informants across development. Genetic influences on antisocial behavior at 14–17 years were entirely shared with those on antisocial behavior at 10–13 years according to both informants. Genetic influences on antisocial behavior at 14–17 years were distinct from those at 4–9 years, however. These age differences in genetic influences cannot be fully distinguished from informant differences across age, but the present findings indicate that youth reported to be persistently antisocial during childhood and adolescence are influenced by one set of genetic factors influencing parent-report conduct problems in childhood and a second set of genetic influences on youth-reported delinquency that come into play around the time of the pubertal transition. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Genetic and environmental influences on antisocial behavior: A meta-analysis of twin and adoption studies.

A meta-analysis of 51 twin and adoption studies was conducted to estimate the magnitude of genetic and environmental influences on antisocial behavior. The best fitting model included moderate proportions of variance due to additive genetic influences (.32), nonadditive genetic influences (.09), shared environmental influences (.16), and nonshared environmental influences (.43). The magnitude of familial influences (i.e., both genetic and shared environmental influences) was lower in parent-offspring adoption studies than in both twin studies and sibling adoption studies. Operationalization, assessment method, zygosity determination method, and age were significant moderators of the magnitude of genetic and environmental influences on antisocial behavior, but there were no significant differences in the magnitude of genetic and environmental influences for males and females. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The etiology of associations between negative emotionality and childhood externalizing disorders.

Despite consistent documentation of associations between childhood negative emotionality and externalizing psychopathology, few genetically informative studies have investigated the etiology of that association. The goal of the current study was to delineate the etiology of the covariation of negative emotionality and childhood externalizing problems (e.g., oppositional defiant disorder, conduct disorder, inattention, and hyperactivity/impulsivity). Twin families were recruited from Georgia state birth records and completed parental report questionnaires of negative emotionality and common Diagnostic and Statistical Manual of Mental Disorders (4th ed., text rev.; American Psychiatric Association, 2000) child psychiatric disorders. Results suggest both genetic and environmental influences underlying negative emotionality and each externalizing symptom dimension, with additional evidence for sibling competition/rater contrast effects for inattention and hyperactivity/impulsivity. Bivariate model-fitting analyses indicated that a portion of the additive (43%–75%) and nonadditive (26%–100%) genetic influences underlying each symptom dimension was accounted for by the genetic influences underlying negative emotionality. Finally, an independent pathways model examining the etiology of the association between negative emotionality and the externalizing dimensions indicated that a substantial portion of the additive genetic, nonadditive genetic, and nonshared environmental influences underlying externalizing behavior is shared with negative emotionality. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Retrospective reports of parental physical affection and parenting style: A study of Finnish twins.

Individual differences in parenting behaviors are due, in part, to genetic factors. In the present study, the authors sought to determine whether the degree of genetic influence varied according to the type of parental behavior under consideration. A population-based sample of 2,334 pairs of Finnish twins provided ratings on the physical affection, control, abusiveness, and indifference shown by their father and mother during childhood. Genetic influences, shared environmental influences, and nonshared environmental influences accounted for a small-to-medium proportion (17%-30%), a small-to-large proportion (22%-44%), and a medium-to-large proportion (37%-55%) of the variance in each parenting measure, respectively. There were no significant differences in effect sizes for mothers and fathers or across the 4 types of parental behavior. The genetic results may reflect characteristic styles with which parents respond to genetically influenced behaviors of individuals (gene-environment correlations) or individual perceptions of this relationship (gene-person correlation processes). The findings have implications for intervention and prevention work with families and for interpretation of evidence for interactions between genes and parenting behaviors. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Co-occurrence of depressive symptoms and antisocial behavior in adolescence: A common genetic liability.

Recent reviews of research on child and adolescent psychopathology have highlighted the consistently high rates of co-occurring dimensions of psychopathology, particularly between internalizing and externalizing disorders, and have suggested that further research examining the causes of co-occurring syndromes is needed. The authors examined this question in a national sample of 720 same-sex adolescent siblings between 10 and 18 years of age consisting of monozygotic and dizygotic twins, full siblings, half siblings, and unrelated siblings. Composite measures of adolescent and parent reports and observational measures of depressive symptoms and antisocial behavior were subjected to behavioral genetic models that examine the genetic and environmental influences on individual differences in each dimension as well as in the co-occurrence between dimensions. Results indicated that approximately half of the variability in depressive symptoms and antisocial behavior is attributed to genetic factors; shared and nonshared environmental influences were also significant. The co-occurrence of depressive and antisocial symptoms was explained by genetic and shared and nonshared environmental influences. Specifically, approximately 45% of the observed covariation between depressive and antisocial symptoms could be explained by a common genetic liability. Results are interpreted in light of contribution of genetic studies to debates on child and adolescent psychopathology. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Genetic and environmental bases of childhood antisocial behavior: A multi-informant twin study.

Genetic and environmental influences on childhood antisocial and aggressive behavior (ASB) during childhood were examined in 9- to 10-year-old twins, using a multi-informant approach. The sample (605 families of twins or triplets) was socioeconomically and ethnically diverse, representative of the culturally diverse urban population in Southern California. Measures of ASB included symptom counts for conduct disorder, ratings of aggression, delinquency, and psychopathic traits obtained through child self-reports, teacher, and caregiver ratings. Multivariate analysis revealed a common ASB factor across informants that was strongly heritable (heritability was .96), highlighting the importance of a broad, general measure obtained from multiple sources as a plausible construct for future investigations of specific genetic mechanisms in ASB. The best fitting multivariate model required informant-specific genetic, environmental, and rater effects for variation in observed ASB measures. The results suggest that parents, children, and teachers have only a partly "shared view" and that the additional factors that influence the "rater-specific" view of the child's antisocial behavior vary for different informants. This is the first study to demonstrate strong heritable effects on ASB in ethnically and economically diverse samples. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Genetic and Environmental Mechanisms Underlying Stability and Change in Problem Behaviors at Ages 3, 7, 10, and 12.

Maternal ratings on internalizing (INT) and externalizing (EXT) behaviors were collected in a large, population-based longitudinal sample. The numbers of participating twin pairs at ages 3, 7, 10, and 12 were 5,602, 5,115, 2,956, and 1,481, respectively. Stability in both behaviors was accounted for by genetic and shared environmental influences. The genetic contribution to stability (INT: 43%; EXT: 60%) resulted from the fact that a subset of genes expressed at an earlier age was still active at the next time point. A common set of shared environmental factors operated at all ages (INT: 47%; EXT: 34%). The modest contribution of nonshared environmental factors (INT: 10%; EXT: 6%) could not be captured by a simple model. Significant age-specific influences were found for all components, indicating that genetic and environmental factors also contributed to changes in problem behavior. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Etiology and measurement of relational aggression: A multi-informant behavior genetic investigation.

Although the study of relational aggression is gaining attention in the literature, little is known about the underlying causes of this behavior and the relative validity of various informants. These issues were addressed in a sample of 1,981 6- to 18-year-old twin pairs (36% female, 34% male, 30% opposite-sex). Relational aggression was assessed via maternal and self-report using a structured interview. Univariate models estimated genetic and environmental influences by informant and examined evidence for gender differences. A psychometric model combined data from both informants to estimate etiologic influences that were both common to the informants and informant specific. In both sexes, the latent variable reflecting the mother’s and child’s shared perception of the child’s relational aggression was substantially influenced by both additive genetic (63%) and shared environmental (37%) influences, although this latent variable accounted for much greater variance in the maternal report (66%) than it did in the youth report (9%). In addition, informant-specific additive genetic and shared environmental influences were found only for the youth report, with all remaining variance in the mother’s report attributed to nonshared environmental influences. Results are discussed in the context of measuring relational aggression and the importance of multiple informants. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Child and adolescent conduct disorder substantially shares genetic influences with three socioemotional dispositions.

In a representative sample of twin children and adolescents, we tested the hypothesis that a substantial proportion of the genetic and environmental influences underlying conduct disorder (CD) are shared with three socioemotional dispositions: Prosociality, Negative Emotionality, and Daring. Caretaker ratings of each dispositional dimension were uniquely associated with a latent CD dimension that included both caretaker- and youth-reports of CD as indicators. Behavior genetic analyses indicated that moderate-to-high additive genetic and moderate nonshared environmental influences underlie all three dispositions and CD, with modest shared environmental influences on Prosociality. Forty percent of the additive genetic influences and all of the nonshared environmental influences on the latent CD dimension were shared in common with the three socioemotional dispositions. The finding that CD shares a substantial proportion of its genetic influences with three distinct socioemotional dispositions suggests new perspectives on the heterogeneous etiology of CD and new approaches to exploring its specific etiological mechanisms. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Continuity and change in children's social maladjustment: A developmental behavior genetic study.

Two developmental models were used to study genetic and environmental mechanisms underlying continuity and change in children's maladjustment. The transmission model assumed that successive levels of functioning were causally linked and that earlier experiences or prior genetic influences affected later maladjustment. The liability model related continuity in problem behavior to stable underlying environmental or genetic factors. The analyses pertained on average to 436 pairs of full siblings, 119 pairs of half siblings, and 122 pairs of cousins for whom maternal ratings of problem behaviors were available at ages 4–6, 6–8, and 8–10. Nonshared environmental influences appeared to be most important for changes in children's problem behaviors and did not have significant effects on age-to-age continuity. To represent the genetic and shared environmental mechanisms underlying stability in problem behavior, the authors preffered liability models without time specific effects. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Age differences in genetic and environmental influences on eating attitudes and behaviors in preadolescent and adolescent female twins.

A sample of 680 11- and 602 17-year-old female twins was used to examine (a) age differences in genetic and environmental influences on disordered eating attitudes and behaviors and (b) associations between body mass index (BMI) and eating attitudes and behaviors. Univariate, biometrical model-fitting analyses indicated that 11-year-old twins exhibited less genetic and greater shared environmental influence on eating attitudes and behaviors than 17-year-old twins. Bivariate model-fitting analyses indicated that the relationship between BMI and eating attitudes was mediated primarily by common shared environmental influences in 11-year-old twins and common genetic influences in 17-year-old twins. Nonetheless, the majority of genetic influences on eating attitudes and behaviors in older twins were due to genetic effects that are independent of those operating in BMI. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Developmental genetic studies of adult personality.

Investigated genetic determinants of personality development and vulnerability to environmental influences during young adulthood, using a longitudinal twin study design. 133 college-age twin pairs completed an abbreviated MMPI twice over a period of 4.5 yrs at ages 20 and 25 yrs. Of the 6 MMPI scales investigated, significant genetic variance was found for 4 at both time periods (Wiggins's Social Maladjustment, Schizophrenia, Welsh A, and D?? scales). Two scales (Psychopathic Deviate and Wiggins's Religiosity) showed significant genetic variance at age 20 but not at age 25. There were no significant genetic influences on directional developmental change over time, and instead, idiosyncratic environmental influences appeared most important for the developmental profiles. In contrast, significant genetic influences were present for generalized vulnerability, or instability, for the Sc scale. (61 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The origins of diverse domains of mathematics: Generalist genes but specialist environments.

The authors assessed 2,502 ten-year-old children, members of 1,251 pairs of twins, on a Web-based battery of problems from 5 diverse aspects of mathematics assessed as part of the U.K. national curriculum. This 1st genetic study into the etiology of variation in different domains of mathematics showed that the heritability estimates were moderate and highly similar across domains and that these genetic influences were mostly general. Environmental factors unique to each twin in a family (rather than shared by the 2 twins) explained most of the remaining variance, and these factors were mostly specific to each domain. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Adolescents' relationships to siblings and mothers: A multivariate genetic analysis.

Research has consistently demonstrated that children's behavior toward their siblings tends to resemble interactions occurring in the parent–child relationship. This study examined the relative contributions of genetic and environmental influences to the covariation between sibling relationships and mother–adolescent relationships. Reported and observed family interactions were assessed for 719 same-sex sibling pairs of varying degrees of genetic relatedness. The covariance between mother–adolescent and sibling interactions was decomposed into genetic, shared, and nonshared environmental components. The overlapping effects of shared environment on the two relationship subsystems explained most of the covariance. Smaller but significant genetic and nonshared environmental effects were also found. The consistency of these findings with family processes, such as modeling, is discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A Genetically Informed Study of Marital Instability and Its Association With Offspring Psychopathology.

Parental divorce is associated with a number of emotional and behavioral problems in young-adult offspring, but theoretical and empirical considerations suggest that the relation may be partially or fully accounted for by passive gene-environment correlation or environmental selection characteristics. The current study used the Children of Twins Design to explore whether shared environmental or genetic factors confound the relationship between parental marital instability and measures of psychopathology. Comparisons of the offspring of adult twins in Australia on 3 factors of abnormal behavior, including drug and alcohol, behavioral, and internalizing problems, suggest that environmental influences associated with divorce account for the higher rates of psychopathology. The results are consistent with a causal connection between marital instability and psychopathology in young-adult offspring. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

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. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Differential association of family subsystem negativity on siblings' maladjustment: using behavior genetic methods to test process theory.

This study investigated the family context of adolescent sibling similarity and differentiation in maladjustment (antisocial behavior and depression) by examining negativity in different subsystems. Two hypotheses were proposed: (1) Parental and sibling negativity tends to diffuse through the family system, especially because of the high level of reciprocity in sibling relationships, leading to sibling similarity; and (2) interparental (coparenting) conflict disrupts cohesive functioning and thereby motivates and facilitates sibling differentiation and niche picking. To control for the effects of similar genes between siblings, the authors used behavioral genetic models with a genetically informed sample of 720 two-parent families, each with at least 2 adolescent siblings. Results for the differences in shared environmental influences across groups high and low in each of the domains of family negativity provided partial support for the hypotheses. The results further understanding of influences on individual differences and support a theory of how parent-child and interparental relationships intersect with sibling relationship dynamics. (PsycINFO Database Record (c) 2010 APA, all rights reserved)