COOCCURRENCE OF DEPRESSIVE SYMPTOMS AND ANTISOCIAL-BEHAVIOR IN ADOLESCENCE - A COMMON GENETIC LIABILITY

Recent reviews of research on child and adolescent psychopathology hav e highlighted the consistently high rates of co-occurring dimensions o f psychopathology, particularly between internalizing and externalizin g disorders, and have suggested that further research examining the ca uses of co-occurring syndromes is needed. The authors examined this qu estion ina 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 measu res of adolescent and parent reports and observational measures of dep ressive symptoms and antisocial behavior were subjected to behavioral genetic models that examine the genetic and environmental influences o n individual differences in each dimension as well as in the co-occurr ence between dimensions. Results indicated that approximately half of the variability in depressive symptoms and antisocial behavior is attr ibuted to genetic factors; shared and nonshared environmental influenc es were also significant. The cooccurrence of depressive and antisocia l symptoms was explained by genetic and shared and nonshared environme ntal influences. Specifically, approximately 45% of the observed covar iation between depressive and antisocial symptoms could be explained b y a common genetic liability. Results are interpreted in light of cont ribution of genetic studies to debates on child and adolescent psychop athology.