Comorbid disorders as moderators of response to family interventions among adolescents with bipolar disorder

Background: While family interventions have shown efficacy in improving mood symptoms and family functioning in pediatric bipolar disorder, few studies have examined the effects of comorbid psychiatric conditions on patients' symptomatic or functional responses to treatment. Methods: 145 adolescents with bipolar I or II disorder were randomly assigned to family-focused therapy (FFT-A) or a brief psychoeducational therapy (enhanced care; EC) and followed over 2 years. Participants received pharmacotherapy for the study's duration. We examined whether comorbid anxiety disorders, attention-deficit/hyperactivity disorder (ADHD), and disruptive behavior disorders (DBDs; i.e., oppositional defiant and conduct disorder) predicted the proportion of weeks that participants experienced mood symptoms during follow-up, and whether comorbid disorders moderated the effects of treatment assignment on mood symptoms and family conflict. Results: Comorbid anxiety was associated with a greater proportion of weeks with depressive symptoms, more severe (hypo) manic symptoms during follow-up, and greater family conflict over the 2-year study. Comorbid ADHD was associated with a greater proportion of weeks with (hypo) manic symptoms, more severe (hypo) manic symptoms, and greater family conflict. Additionally, youth with comorbid ADHD who received FFT-A had more favorable trajectories of (hypo) manic symptoms and family functioning than youth with comorbid ADHD who received EC. Comorbid DBDs were consistently associated with more severe depressive symptoms and greater family conflict throughout the study. Limitations: Randomization to treatments was not stratified on comorbid disorders. The longitudinal trajectories of anxiety, attentional, and disruptive behavior symptoms were not examined. Conclusions: The course of bipolar disorder in adolescents is strongly affected by comorbid disorders. Future research should examine whether adolescents with more complex presentations of bipolar disorder should be treated with different or more intensive psychosocial protocols than adolescents without these presentations.