Delayed sleep-wake phase disorder may be a predictor of relapse in euthymic patients with bipolar disorder, according to a prospective study, reports Psychiatry Advisor.

Up to half of patients with bipolar disorder experience recurrence or relapse each year, despite adhering to treatment, thus calling for preventive strategies. Among previously identified factors found to predict such relapse are presence of residual depressive or manic symptoms at initial recovery, number of days of elevated mood in the preceding year, mixed urban/rural area living setting, and early age of onset.

The presence of subsyndromal symptoms was also found to predict relapse/recurrence of bipolar disorder. Accumulating evidence indicates that dysregulation of the circadian rhythm is a frequent comorbidity of bipolar disorder.