Oppositional defiant and conduct disorders: issues to be resolved for DSM-IV.

Oppositional defiant disorder (ODD) and conduct disorder (CD) are reasonably distinct both in terms of statistical covariation among symptoms and ages of onset. The two disorders are related in similar ways to impairment and family history of antisocial behavior, but the association is stronger for CD than ODD. Virtually all clinic-referred youths with prepubertal onset of CD have retained the symptoms of ODD that emerged at earlier ages. Furthermore, a set of serious antisocial behaviors characteristically emerges at later ages in some youths with CD, suggesting further developmental progression within CD. These findings are consistent with a conceptualization of ODD and CD as developmentally staged, hierarchically organized levels of severity of the same disorder, but two findings argue for distinguishing separate disorders in DSM-IV: (1) many youths with ODD never develop CD, and (2) CD that emerges for the first time in adolescence appears to be independent of ODD.