Comorbidity between disruptive disorders and depression in referred adolescents.

Parent questionnaires from large Australian (N = 2093) and American (N = 500) clinic cohorts of adolescents were used to diagnose depression, attention deficit disorder with hyperactivity, and oppositional and conduct disorders. Co-occurrence of diagnoses was very high. Comorbidity between depression and conduct disorder was not higher than that expected for any psychiatric disorder (odds ratios = 1.20 and 1.45 respectively for each cohort) while comorbidity between attention deficit disorder with hyperactivity and oppositional disorder was higher than expected (odds ratios = 7.03 and 9.02) but comparable to that between conduct and oppositional disorder (odds ratios = 7.35 and 6.14). Co-occurrence of depression with other disorders did not increase the likelihood of comorbid conduct disorder.