Circadian preference in bipolar disorder

PurposeA role for circadian rhythm abnormalities in the pathogenesis of bipolar disorder (BD) has been suggested. The present study assessed circadian preference, a subjective preference for activities in the morning or evening related to chronotype.MethodsThe sample was comprised of 81 outpatients with BD in remission and 79 control subjects. Circadian preference was derived from an interview evaluating biological rhythms and sleep pattern from the Pittsburgh Sleep Quality Index.ResultsPatients were significantly more likely to have an evening preference than control subjects. Circadian preference was also associated with sleep latency.ConclusionsThe association of evening preference and longer sleep latency may be related to the frequent clinical observation of a sleep/wake cycle reversal in bipolar disorder.