Longitudinal Course of Bipolar Disorder in Youth With High-Functioning Autism Spectrum Disorder.

OBJECTIVE: To provide the first longitudinal characterization of mood and psychosocial functioning in youth with comorbid bipolar (BD) and autism spectrum (ASD) disorders.

METHOD: The Course and Outcome of Bipolar Youth study followed 368 youth (aged 7-17 years) with DSM-IV bipolar I (BP-I), BP-II, or Not Otherwise Specified (NOS) for, on average, 9 years using the Longitudinal Interval Follow-up Evaluation. This subgroup analysis compared youth with and without ASD on clinical presentation, percentage of time with mood symptomatology, and psychosocial functioning.

RESULTS: Thirty youth (∼8%) met DSM-IV criteria for Asperger's disorder or pervasive developmental disorder-NOS (referred to here as ASD). Lifetime worst episode severity was similar in both groups, but youth with both BD and ASD (BD+ASD) had elevated rates of comorbid attention-deficit/hyperactivity and obsessive-compulsive disorders, were younger at intake, and had an earlier onset of mood symptoms. Over time, in both groups, the proportion of predominantly euthymic youth increased, and episode recurrence decreased. Compared to youth with BD, the clinical presentation of youth with BD+ASD more frequently involved distractibility, racing thoughts, depressed mood, social withdrawal, and low reactivity of negative mood states. ASD-related symptomatic differences were generally strongest early and decreased over time. Youth with BD+ASD had significantly greater impairment in friendships throughout follow-up.

CONCLUSION: Youth with BD+ASD exhibit typical BD mood symptoms but with earlier onset, mixed symptom presentation, and additive functional impairments. Significant amelioration of clinical symptoms occurred over time, suggesting that early recognition and treatment of mood disorders in youth with ASD may improve clinical outcomes.