Heritability of Antisocial Behaviour at 9: Do Callous-Unemotional Traits Matter? (original) (raw)
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Journal of Child Psychology and Psychiatry, 2003
Background: Early childhood antisocial behaviour is a strong prognostic indicator for poor adult mental health. Thus, information about its etiology is needed. Genetic etiology is unknown because most research with young children focuses on environmental risk factors, and the few existing studies of young twins used only mothersÕ reports of behaviour, which may be biased. Method: We investigated genetic influences on antisocial behaviour in a representative-plus-high-risk sample of 1116 pairs of 5year-old twins using data from four independent sources: mothers, teachers, examiner-observers previously unacquainted with the children, and the children themselves. Results: Children's antisocial behaviour was reliably measured by all four informants; no bias was detected in mothersÕ, teachersÕ, examinersÕ, or children's reports. Variation in antisocial behaviour that was agreed upon by all informants, and thus was pervasive across settings, was influenced by genetic factors (82%) and experiences specific to each child (18%). Variation in antisocial behaviour that was specific to each informant was meaningful variation, as it was also influenced by genetic factors (from 33% for the children's report to 71% for the teachersÕ report). Conclusions: This study and four others of very young twins show that genetic risks contribute strongly to population variation in antisocial behaviour that emerges in early childhood. In contrast, genetic risk is known to be relatively modest for adolescent antisocial behaviour, suggesting that the early-childhood form has a distinct etiology, particularly if it is pervasive across situations.
Child Psychiatry & Human Development
The developmental course of antisocial behavior is often described in terms of qualitatively distinct trajectories. However, the genetic etiology of various trajectories is not well understood. We examined heterogeneity in the development of delinquent and aggressive behavior in 1532 twin youth using four waves of data collection, spanning ages 9-10 to 16-18. A latent class growth analysis was used to uncover relevant subgroups. For delinquent behavior, three latent classes emerged: Non-Delinquent, Low-Level Delinquent, and Persistent Delinquent. Liability for persistent delinquency had a substantial genetic origin (heritability = 67%), whereas genetic influences were negligible for lower-risk subgroups. Three classes of aggressive behavior were identified: Non-Aggressive, Moderate, and High. Moderate heritability spanned the entire continuum of risk for aggressive behavior. Thus, there are differences between aggressive behavior and non-aggressive delinquency with respect to heterogeneity of etiology. We conclude that persistent delinquency represents an etiologically distinct class of rule-breaking with strong genetic roots.
Purpose: This study investigated genetic and environmental commonalities and differences between aggressive and non-aggressive antisocial behavior (ASB) in male and female child and adolescent twins, based on a newly developed self-report questionnaire with good reliability and external validitythe Self-Report Delinquency Interview (SR-DI). Methods: Subjects were 780 pairs of twins assessed through laboratory interviews at three time points in a longitudinal study, during which the twins were: (1) ages 9-10 years; (2) age 11-13 years, and (3) age 16-18 years. Results: Sex differences were repeatedly observed for mean levels of ASB. In addition, diverse change patterns of genetic and environmental emerged, as a function of sex and form of ASB, during the development from childhood to adolescence. Although there was some overlap in etiologies of aggressive and non-aggressive ASB, predominantly in shared environmental factors, their genetic overlap was moderate and the non-shared environmental overlap was low. Conclusions: Taken together, these results reinforced the importance of differentiating forms of ASB and further investigating sex differences in future research. These results should be considered in future comparisons between youth self-report and parental or teacher report of child and adolescent behavior, and may help elucidate commonalities and differences among informants.
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 parent, 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.
BEHAVIORAL GENETICS: THE SCIENCE OF ANTISOCIAL BEHAVIOR
Social scientists generally agree that a paradigm shift has occurred over the course of the last three decades of research in human behavior: the zeitgeist has moved away from a culturally centered, social learning model towards a more balanced perspective in which both genetic and environmental factors are understood to explain the wide variations observed in human behavior. This perspective now applies in the areas of mental health and illness, as well as across several domains of normal, varying psychological constructs, such as intelligence, personality, interests, and attitudes. The study of antisocial behavior is no exception to this paradigm shift. There is now abundant evidence that both genetic and environmental influences —and probably their interaction—are of major importance in explaining individual differences in antisocial behavior, including differences in criminal behavior. Evidence for a genetic basis of antisocial behavior stems from several different lines of research. First, behavioral genetic studies of twins and adoptees have demonstrated that heredity plays a role in antisocial behavior, including various forms of aggression and criminality, by finding greater concordance for such behavior in genetically related individuals compared to nonrelatives living in the same environment. Second, various correlates of antisocial behavior, including personality factors such as impulsivity, sensation-seeking, risk-taking, and callous-unemotional traits, are known to be at least partly genetically influenced. Third, psychiatric outcomes related to antisocial behavior, including antisocial personality disorder, gambling, and substance use and abuse, have also been investigated in genetically informative designs, and each of these has demonstrated significant genetic influence. This paper summarizes the heritability of each of these aspects or correlates of antisocial behavior and discusses research attempting to unpack the genetic and environmental " black boxes " involved in antisocial behavior, including studies investigating the influence of both biological and social risk factors and how they might be mediated by genetic and environmental factors. Examples of biological risk factors could be neurotransmitters, physiological arousal, frontal lobe function, and hormones, while social risk factors would include socioeconomic status, peer characteristics, and parental monitoring and discipline. Biological risk factors may not necessarily be entirely genetically based, and social risk factors may not be purely environmental in origin; this highlights the complexity of the relationships between risk factors and antisocial behavior. This paper also reports studies that have identified specific genetic associations with antisocial behavior. Yet genetic predispositions, though important, are more deleterious in the presence of adverse environments. This view dovetails with other biosocial theories of antisocial behavior in which the effects of biological risk factors have been found to be moderated by social circumstances. An overarching biosocial model of antisocial behavior is presented here,
Changes in heritability across increasing levels of behavior problems in young twins
Behavior Genetics, 1996
The present study addresses the issue of differential heritability with increasing severity of parent-reported internalizing and externalizing behavior problems assessed by the Child Behavior Checklist. The sample includes 526 identical and 389 fraternal samesexed twin pairs from five national birth cohorts, aged 5~5, 8-9, and 12-15 years. Heritability (h2), common environment (c2), and changes in these parameters as a function of proband score were analyzed by multiple regression models (Cherny et al., 1992). Internalizing and externalizing behavior showed significant heritability. A small increment in h 2 and a reduction of c z with increasing severity of externalizing behavior were independent of sex and age. For internalizing behavior h z increased and e 2 declined with increasing severity for the 5-6 and 8-9 year olds. Logarithmic transformation of scores lowered h 2 and increased c 2, particularly for externalizing behavior. The 'changes in heritability with severity were nonsignificant for the transformed variables.
Genetics of Callous-Unemotional Behavior in Children
PLoS ONE, 2013
Callous-unemotional behavior (CU) is currently under consideration as a subtyping index for conduct disorder diagnosis. Twin studies routinely estimate the heritability of CU as greater than 50%. It is now possible to estimate genetic influence using DNA alone from samples of unrelated individuals, not relying on the assumptions of the twin method. Here we use this new DNA method (implemented in a software package called Genome-wide Complex Trait Analysis, GCTA) for the first time to estimate genetic influence on CU. We also report the first genome-wide association (GWA) study of CU as a quantitative trait. We compare these DNA results to those from twin analyses using the same measure and the same community sample of 2,930 children rated by their teachers at ages 7, 9 and 12. GCTA estimates of heritability were near zero, even though twin analysis of CU in this sample confirmed the high heritability of CU reported in the literature, and even though GCTA estimates of heritability were substantial for cognitive and anthropological traits in this sample. No significant associations were found in GWA analysis, which, like GCTA, only detects additive effects of common DNA variants. The phrase 'missing heritability' was coined to refer to the gap between variance associated with DNA variants identified in GWA studies versus twin study heritability. However, GCTA heritability, not twin study heritability, is the ceiling for GWA studies because both GCTA and GWA are limited to the overall additive effects of common DNA variants, whereas twin studies are not. This GCTA ceiling is very low for CU in our study, despite its high twin study heritability estimate. The gap between GCTA and twin study heritabilities will make it challenging to identify genes responsible for the heritability of CU.
Genetic influences on the overlap between low IQ and antisocial behavior in young children
Journal of Abnormal Psychology, 2006
The well-documented relation between the phenotypes of low IQ and childhood antisocial behavior could be explained by either common genetic influences or environmental influences. These competing explanations were examined through use of the Environmental Risk Longitudinal Twin Study 1994-1995 cohort (Moffitt & the E-Risk Study Team, 2002) of 1,116 twin pairs and their families. Children's IQ was assessed via individual testing at age 5 years. Mothers and teachers reported on children's antisocial behavior at ages 5 and 7 years. Low IQ was related to antisocial behavior at age 5 years and predicted relatively higher antisocial behavior scores at age 7 years when antisocial behavior at age 5 years was controlled. This association was significantly stronger among boys than among girls. Genetic influences common to both phenotypes explained 100% of the low IQ-antisocial behavior relation in boys. Findings suggest that specific candidate genes and neurobiological processes should be tested in relation to both phenotypes. Keywords IQ; antisocial behavior; young children; behavior genetics Early-onset antisocial behavior is a strong risk factor for poor mental health, criminality, unemployment, and a host of other adjustment problems in adult life (Moffitt, Caspi, Harrington, & Milne, 2002; Robins, 1966). Understanding the etiology of antisocial behavior in young children is necessary for informing prevention efforts and, therefore, remains an important public health goal. Low IQ is a consistent risk factor for emergence and continuity of antisocial behavior across the life course in both prospective and cross-sectional studies, even when other relevant risk factors are statistically controlled (Hinshaw, 1992; Moffitt & Lynam, 1994; Nigg & Huang-Pollock, 2003; Simonoff et al., 2004). The effect size of the association between low IQ and antisocial behavior ranges from small to medium, with correlations ranging from .20 to .30 across studies, and comparisons of antisocial groups and control groups show half a standard deviation (approximately 8 points) difference in their IQ scores. These findings have been replicated in cohorts throughout the Western world (Hinshaw, 1992; Nigg & Huang-Pollock, 2003). Although the bulk of studies involve adolescents, the
Journal of Abnormal Psychology, 2009
It is necessary to determine if causal influences on developing antisocial behavior change with age to guide both research and theory on its origins. We estimated the extent to which the same genetic factors influence antisocial behavior across 4-17 years of age using 2,482 sibling pairs of varying genetic relatedness. Assessments of antisocial behavior reflected the changing validity of informants across development: Mothers (4-9 years), mothers and youth (10-13 years), and youth (14-17 years). 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.