BACKGROUND: Twelve adolescents found to be the most problematic, crisis prone, and treatment resistant were comprehensively reevaluated in the special educational day school and treatment program they were attending. This reevaluation took place over a 6-month period and was done to arrive upon a more comprehensive diagnostic understanding so that more relevant and effective treatment measures could be instituted. METHOD: The author conducted semistructured interviews with the adolescents on multiple occasions as the clinical situations warranted. All information available, recorded or otherwise, was comprehensively reviewed and reevaluated. The children were observed informally in and out of their classrooms throughout the period. All parents available were interviewed to clarify the children's present and past symptomatology and to assess the nature of psychiatric disorders, if any, in first- and second-degree family members. RESULTS: The reevaluation showed that 8 of the 12 youngsters clearly satisfied DSM-III-R criteria for bipolar disorder, which had been misdiagnosed mainly as attention-deficit hyperactivity disorder (ADHD) and conduct disorder. Three other youngsters showed significant bipolar features though not fully satisfying the criteria for this disorder. CONCLUSION: Bipolar disorder may be very common among highly problematic adolescents in special educational and outpatient treatment facilities for emotionally disturbed youngsters but may still be misdiagnosed very often as ADHD and conduct disorder, with all the negative consequences of such misdiagnosis.