Sleep disturbance plays several key roles in bipolar disorder (BD). From a diagnostic perspective, insomnia and hypersomnia are criteria for a depressive episode, while decreased need for sleep is a highly specific symptom for a manic episode.1,2 Sleep disturbance is the most common prodromal symptom preceding mania, and the duration of sleep observed early in the course of psychiatric hospitalization may predict the speed of recovery from a manic episode.3,4 Even during euthymic periods, patients with BD frequently struggle with sleep difficulties, which may affect quality of life and the choice of pharmacotherapy and increase the likelihood of major mood episode recurrence.5