Confirming the etiology of adolescent acting-out behaviors: an examination of observer-ratings in a sample of adoptive and biological siblings.

Background: A recent meta-analysis revealed moderate shared environmental influences (C) on most forms of child and adolescent psychopathology (Burt, 2009), including antisocial behavior. Critically, however, the research analyzed in this meta-analysis relied largely on specific informant-reports (and particularly parent and child reports), each of which is subject to various sources of rater bias. Observer-ratings of children's behaviors avoid many of these biases, and are thus well suited to verify the presence of C. Given this, we sought to buttress the evidence supporting C in two key ways. First, we sought to confirm that C contributes to observer-ratings in a sample of adoptive siblings, as similarity between adoptive siblings constitutes a 'direct' estimate of C. Second, we sought to confirm that these shared environmental influences persist across informants (i.e., the effects are not specific to the rater or the context in question).

Methods: The current study examined the etiology of observer-ratings of acting-out behaviors, as well as sources of etiological overlap across observer-ratings, adolescent self-report and maternal-report in sample of over 600 biological and adoptive sibling pairs from the Sibling Interaction and Behavior Study (SIBS).

Results: Results revealed moderate and significant shared environmental influences on observer-ratings (31%), as well as on the other informant-reports (20-23%). Moreover, a portion of these effects overlapped across measures (C correlations ranged from .32 to .34).

Conclusions: Such findings argue against passive gene-environment correlations (rGE) and rater bias as primary explanations for earlier findings of C on antisocial behavior, and in this way, offer a critical extension of prior work indicating that the role of shared environmental influences on child and adolescent antisocial behavior was dismissed too soon.