Further evidence of unique developmental phenotypic correlates of pediatric bipolar disorder: findings from a large sample of clinically referred preadolescent children assessed over the last 7 years

Abstract

BackgroundA comparison of the prevalence, clinical correlates, and patterns of comorbidity among children with bipolar disorder (BPD) assessed in the early 1990s (1st cohort) with those evaluated over the last 7 years (2nd cohort). MethodSubjects in both cohorts were children aged ≤12 years referred to a child psychiatry service and evaluated with identical assessment methods. Children with a DSM-III-R BPD diagnosis (1st cohort, n=43; 2nd cohort, n=129) were identified. For comparison purposes, we used attention-deficit/hyperactivity disorder (ADHD) children without BPD referred to the same clinic during the same time period (1st cohort, n=164; 2nd cohort, n=450). ResultsAnalogous to 1st cohort findings, 2nd cohort results showed that (1) mania was identified in 17% of subjects; (2) the clinical picture was predominantly irritable and mixed, and the course was chronic; (3) BPD children frequently met criteria for major depression, ADHD, psychosis, and anxiety disorders; and (4) BPD children had high rates of psychiatric hospitalization and had evidence of severely impaired psychosocial functioning. ConclusionThese findings confirm that pediatric BPD is a severe clinical disorder afflicting a sizable number of referred preadolescent children. Its unique phenotypic features and patterns of comorbidity support the hypothesis that clinically referred pediatric bipolar disorder represents a very severe developmental subtype of bipolar disorder.