Issues of taxonomy and comorbidity in the development of conduct disorder

Abstract A developmental approach to the classification of antisocial behavior is necessary for two reasons. First, although the continuity of antisocial behavior is strong for many individuals, the topography of antisocial behavior changes during the course of development. Second, antisocial behavior apparently develops in at least two separate pathways — child-onset versus adolescent-onset — that differ markedly regarding types of antisocial behavior displayed, persistence, and perhaps etiology. The development of antisocial behavior must also be understood within the context of co-occurring disorders and conditions. Comorbid attention-deficit hyperactivity disorder appears to be associated with greater aggression and a worse prognosis, and comorbid academic underachievement is also associated with a negative course. Emerging evidence also suggests that comorbid anxiety disorder is associated with level of aggression, but the direction of the correlation appears to differ at different ages. In all, full understanding of conduct disorder requires developmentally sensitive classification as well as consideration of comorbid conditions.