Abstract
Recent research examining comorbidity associated with attention deficit hyperactivity disorder (ADHD) has raised the possibility of the existence of subtypes of the disorder. If this is the case, delineating subgroups is clinically imperative. Two hundred seventy nonrepetitive, consecutively admitted children and adolescent inpatients received structured diagnostic interviews (Schedule for Affective Disorders and Schizophrenia in School Aged Children). Twenty-eight percent of these children met the criteria for ADHD. Of those children with an ADHD diagnosis, 68% also met the criteria for an affective disorder. Thirty-six percent met the full criteria for major depression disorder. Eight percent met the criteria for an affective psychosis and 22% were diagnosed with bipolar disorder. There was a significant overlap between ADHD and bipolar disorder, suggesting the possibility of a lack of specificity in the diagnostic instruments used in this population. The results support the clinical necessity of carefully assessing for occult affective illness in all children and adolescents with attention deficit disorder.