Classifying Mood Symptom Trajectories in Adolescents with Bipolar Disorder

Abstract Objective The Course and Outcome of Bipolar Youth study (Birmaher and colleagues) found that children and adolescents with bipolar spectrum disorders followed one of four distinct mood trajectories over 8 years of follow-up, with as many as 25% 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 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 two psychosocial family treatments during the first 9 months of the study, and pharmacotherapy was provided throughout the two years. Using latent class growth analyses (LCGA), we classified participants into distinct courses of illness based on mood ratings collected over the two years. We examined demographic and illness variables as predictors of these course classifications. Results LCGA 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 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.