This is a multicenter, randomized, double-blind, placebo-controlled study in pediatric patients who are experiencing major depressive episodes (MDEs) associated with a primary diagnosis of bipolar I or bipolar II disorder as confirmed by Kiddie Schedule for Affective Disorders and Schizophrenia for School-Age Children-Present and Lifetime Version (K-SADS-PL), according to criteria of the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM 5).