Objectives: As outlined in the social zeitgeber hypothesis, social rhythm disrupting (SRD) life events begin a cascade of social and biological rhythm disruption that may lead to the onset of affective episodes in those vulnerable to bipolar disorder. Thus, the study of SRD events is particularly important in individuals with this chronic condition. The purpose of the current study was to evaluate (i) the extent to which SRD life events increased the risk of recurrence of a bipolar mood episode, and (ii) whether the social rhythm disruption associated with the event conferred an increased risk of recurrence, after accounting for the level of threat associated with the life event.
Methods: We examined the effect of SRD events on recurrence during preventative treatment in a sample of 118 patients with bipolar disorder who achieved remission from an acute episode after receiving psychotherapy and pharmacotherapy. Life events were measured with the Bedford College Life Events and Difficulty Schedule and were rated for degree of SRD and threat.
Results: Time-dependent Cox proportional hazards models showed that having a higher SRD rating was significantly associated with an increased risk of recurrence, even when accounting for the threat effect of a life event and psychosocial treatment (hazard ratio = 1.33, 95% confidence interval: 1.04-1.70, p = 0.023). However, this finding fell below conventional levels of statistical significance when accounting for other covariates.
Conclusions: Our findings lend partial support to the social zeitgeber hypothesis.
Keywords: life events; mood; recurrence; social rhythms; social zeitgeber; threat.
© 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.