Chunk #49 — Discussion — Structure and Etiology of Behavioral Disinhibition Components Across Adolescence — Individual components of behavioral disinhibition
A similar yet much smaller shift in the pattern of twin resemblance from age 12 to 17 was observed for conduct disorder, which also lowered the estimate of heritability at Wave 2. Our data suggest that early substance use and conduct problems are more heritable than in late adolescence when some substance experimentation and delinquency may be more normative and, importantly, influenced by family, neighborhood, and peers contributing to shared environmental variance. Although published heritability estimates for adolescent conduct problems have been variable, likely due to differences in method of assessment (e.g., instrument, informant) and age at which the behaviors were studied, a recent review and meta-analysis of 51 available twin and adoption studies (Rhee & Waldman, 2002) suggests that approximately one third of the variation in antisocial behavior can be accounted for by genetic factors. Moreover, a recent study of preadolescent twins showed that combining behavioral data from multiple informants (i.e., child, parent, teacher) captures an index of conduct problems that are highly heritable (a2 = .96; Baker, Jacobson, Raine, Lozano, & Bezdijian, 2007). The fact that we were also able to use a multi-method, multi-informant measure of conduct problems may explain our moderate to high estimates of heritability.
