Who are the comorbid adolescents? Agreement between psychiatric diagnosis, youth, parent, and teacher report.

The investigators examined the rates of psychiatric comorbidity for externalizing and internalizing behavior problems, using semistructured diagnostic interview and parent, teacher, and youth report on the Achenbach checklists. The study also evaluated the effects of conjunctive, compensatory, and disjunctive data combination strategies. Using the same data and identical diagnostic thresholds, between 5 and 74% of 189 youths presenting to an outpatient clinic were identified as having comorbid internalizing and externalizing problems. Parent report and semistructured interview indicated the highest comorbidity rates. Despite good cross-source agreement (rs .29-.58), there was very little agreement about which specific youths presented with comorbid internalizing and externalizing problems (kappas .14-.40). Results also indicate that single DSM-IV disorders, such as bipolar disorder, can manifest "comorbid" patterns of behavior problems on checklists.