Social rhythm regularity and the onset of affective episodes in bipolar spectrum individuals.

OBJECTIVES Research suggests that bipolar disorder individuals may have less social rhythm regularity than normal controls and that this may contribute to their affective symptoms and episodes. This study examined whether regularity prospectively predicted time to onset of major depressive, hypomanic and manic episodes in a sample with bipolar spectrum disorders. METHODS We recruited 414 undergraduate students from Temple University and University of Wisconsin diagnosed with cyclothymia, bipolar II disorder, or with no affective disorder (normal controls). Participants completed the Social Rhythm Metric at Time 1 and structured interviews approximately every four months for an average follow-up period of 33 months. RESULTS Participants diagnosed with cyclothymia and bipolar II disorder reported significantly fewer regular activities than normal controls, and approximately half of these participants experienced a worsening course of their illness over the study duration. Survival analyses indicated that both diagnosis and social rhythm regularity significantly predicted the time to participants' first prospective onset of major depressive, hypomanic and manic episodes. CONCLUSION Consistent with the social zeitgeber theory, bipolar spectrum participants reported less social rhythm regularity than normal controls, which prospectively predicted the survival time to affective episodes.