Weintraub MJ, et al. - Considering the Course and Outcome of Bipolar Youth study revealing 4 distinct mood trajectories, one of which is followed by children and adolescents with bipolar spectrum disorders, with as many as 25% of participants showing a predominantly euthymic course, researchers examined whether adolescents with bipolar I and II disorder who participated in a 2-year clinical trial show similar patterns of illness course. They assessed 144 adolescents with bipolar I or II disorder, identified shortly after a mood episode, over a 2-year period. As per latent class growth analyses, four mood trajectories exist for these cases: “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%). Observations revealed maintenance of euthymic states in a substantial proportion (25%−30%) of youth with bipolar I or II disorder over extended periods of follow-up. Recognition of youth who are more and less likely to remain stable over time may assist in psychosocial and pharmacological treatments after an illness episode.