Symptom Dimensions and Trajectories of Functioning Among Bipolar Youth: A Cluster Analysis.

BACKGROUND: Accurate assessment of pediatric bipolar disorder (BD) is important for allocating appropriate treatment, but it is complicated by significant heterogeneity in symptom presentation and high rates of comorbidity. Investigating clinical subtypes of the disorder may help to clarify diagnostic boundaries and inform targeted treatment. This study used a full diagnostic instrument to examine symptom patterns among youth with BD. METHOD: Trained interviewers completed the Washington University Kiddie Schedule for Affective Disorders and Schizophrenia (WASH-U-KSADS) with 71 children (7 to 13 y of age) and families as part of the baseline assessment for a randomized clinical trial of Child- and Family-focused Cognitive-Behavioral Therapy (CFF-CBT) compared with treatment as usual (TAU) for pediatric BD. All participants met DSM-IV-TR criteria for a bipolar spectrum disorder. Hierarchical and K-means cluster analyses were performed. Resultant clusters were compared on symptom severity and psychosocial functioning at baseline and across treatment. RESULTS: Two distinct symptom profiles emerged: "dysregulated/defiant" and "classic presentation." The dysregulated/defiant cluster was characterized by more externalizing and disruptive behaviors, whereas the classic cluster presented with more severe depression, hallmark manic symptoms, anxiety, and inattention. CFF-CBT consistently promoted psychosocial coping skills, such as problem solving and self-control, for the dysregulated/defiant cluster. TAU also promoted these skills among the individuals in the classic presentation group but not those with symptoms in the dysregulated/defiant cluster. DISCUSSION: Pediatric BD may be characterized by distinct phenotypes with unique etiologies and pathways to impairment. The use of a parametric approach to classify the diverse symptom presentations helped yield valuable insights into how to promote the best prognosis for improved functional outcomes in CFF-CBT versus TAU for youth with pediatric BD.