Social and circadian rhythm dysregulation and suicide: A systematic review and meta-analysis

This systematic review of 52 studies provides a quantitative synthesis of the empirical literature on social and circadian rhythm correlates of suicidal thoughts and behaviors (STB). Small-to-medium pooled effect sizes were observed for associations between evening chronotype and STB and suicidal ideation (SI), although the pooled effect size diminished when accounting for publication bias. Three studies employed longitudinal designs and suggested eveningness was predictive of future STB, with a small-to-medium effect size. Social rhythm irregularity was also a significant correlate of STB with pooled effect sizes in the medium range. Overall circadian rhythm disruption was not associated with STB, although certain circadian rhythm metrics, including mean daytime activity, circadian rhythm sleep-wake disorder diagnosis, and actigraphy-assessed amplitude were associated with STB. Pooled effect sizes for these indices were in the medium to large range. There is a need for additional longitudinal research on actigraphy-based circadian parameters and objective markers of circadian phase (i.e., dim-light melatonin onset) to gain a clearer understanding of associations of endogenous circadian function and STB beyond that which can be captured via self-report. •Overall circadian rhythm disruption was not associated with suicidal thoughts and behaviors.•Specific circadian indices, such as actigraphy-assessed amplitude and mean daytime activity were significant correlates.•Three prospective studies provided evidence that evening chronotype may be a risk factor for suicidal thoughts and behaviors.•There was a medium pooled effect size for associations between social rhythm disruption and suicidal thoughts and behaviors.•More studies of actigraphy-derived and endogenous circadian rhythmicity and suicidal thoughts and behaviors are needed.