The impairment of pediatric bipolar sleep: Hypotheses regarding a core defect and phenotype-specific sleep disturbances

BackgroundThe nature of the sleep disturbances associated with different phenotypes of pediatric bipolar disorder is unknown. Most manic children exhibit delayed sleep onset, but only a minority display decreased need for sleep. The DSM-IV manic sleep criterion is inadequate.MethodAll published studies of the sleep characteristics of bipolar children and adolescents are reviewed. Relevant studies of pediatric unipolar depressed subjects, circadian variation of bipolar and sleep variables, and circadian neurobiology are also reviewed. This information forms the basis of hypotheses regarding the core defect of pediatric bipolar sleep and phenotype-specific sleep disturbances of bipolar children and adolescents.LimitationsThe extant research literature is extremely limited. Interpretation of bipolar sleep is confounded by day-to-day variation of bipolar symptoms and sleep parameters, the presence of comorbid conditions, and environmental and psychosocial factors.ConclusionsThe core defect of pediatric bipolar sleep is hypothesized to be a significant delay of the circadian sleep–wake cycle, a form of the delayed sleep-phase syndrome. Children and adolescents with part-day manic cycles and chronic mixed conditions typically will manifest delayed sleep onset, but not decreased need for sleep. Pediatric individuals with days-long manic cycles or chronic mania typically will manifest decreased need for sleep, produced by interaction between the sleep-onset phase delay and bedtime and early morning manic psychomotor acceleration. The sleep-onset phase delay, when expressed, is hypothesized to be a trait marker of bipolar spectrum illness. Revision of the DSM-IV manic sleep criterion is necessary.