Mood disorders and biological rhythms in young adults: A large population-based study

BACKGROUND: It is known that sleep disturbance has been considered a trait-marker of mood disorders. However, the role of disruptions in biological rhythms, such as eating, activity, and social patterns, needs to be better understood. AIM: To assess the differences in biological rhythms in subjects with bipolar disorder, major depressive disorder, and healthy controls. We also tested the association between disruptions of biological rhythms and circadian preferences. METHODS: A cross-sectional, population-based study with a representative sample of 1023 young adults. Bipolar disorder and depression were diagnosed using The Mini International Neuropsychiatric Interview - PLUS and DSM Structured Clinical Interview. Self-reported biological rhythms and circadian preference were assessed using the Biological Rhythm Interview of Assessment in Neuropsychiatry (BRIAN). RESULTS: Bipolar disorders and depression subjects presented higher rates of disruption in biological rhythms when compared to healthy controls even after adjusting for sex, socioeconomic status, alcohol, tobacco, illicit drug use, anxiety disorder and psychotropic medication use. Euthymic subjects showed higher biological rhythm disruption when compared to controls. Higher disruption in biological rhythms was observed in subjects with evening preferences. CONCLUSION: Higher disruption in biological rhythms occurs in individuals with depression and bipolar disorder even on periods of euthymia.