Classifying Mood Symptom Trajectories in Adolescents With Bipolar Disorder

Objective: The Course and Outcome of Bipolar Youth study found that children and adolescents with bipolar spectrum disorders followed 1 of 4 distinct mood trajectories over 8 years of follow-up, with as many as 25% of participants showing a predominantly euthymic course. We evaluated whether similar patterns of illness course are observed in adolescents with bipolar I and II disorder who participated in a 2-year clinical trial. Method: A total of 144 adolescents with bipolar I or II disorder, identified shortly after a mood episode, were assessed over a 2-year period. Participants were randomly assigned to one of 2 psychosocial family treatments during the first 9 months of the study, and pharmacotherapy was provided throughout the 2 years. Using latent class growth analyses, we classified participants into distinct courses of illness based on mood ratings collected over the 2 years. We examined demographic and illness variables as predictors of these course classifications. Results: Latent class growth analyses indicated four mood trajectories: "predominantly euthymic" (29.9% of sample), "ill with significantly improving course" (11.1%), "moderately euthymic" (26.4%), and "ill with moderately improving course" (32.6%). Adolescents in these classes were euthymic 77.7%, 53.6%, 44.1%, and 18.6% of the weeks of follow-up, respectively. Psychosocial treatment condition and baseline medication exposure were not associated with trajectories. However, youth with more severe baseline depressive symptoms, suicidality, lower quality of life scores, and minority race/ethnicity had more symptomatic courses of illness over time. Conclusion: A substantial proportion (25%-30%) of youth with bipolar I or II disorder maintain euthymic states over extended periods of follow-up. Identifying youth who are more and less likely to remain stable over time may help guide psychosocial and pharmacological treatments after an illness episode.