Behavioural sleep and circadian rhythm interventions in bipolar disorder: a systematic review of randomised controlled trials

Abstract

Sleep and circadian rhythm disruptions are prominent symptoms of bipolar disorder (BD) and potential targets for adjunctive behavioural intervention. The aim of this systematic review was to appraise evidence from randomised controlled trials on the effects of behavioural sleep and circadian interventions in BD. Methods: The review included records from inception until January 3rd, 2021 (PROSPERO registration: CRD42019156782). All included trials were summarised via narrative synthesis and meta-analytic models were applied when appropriate. Findings: Nineteen studies met the inclusion/exclusion criteria. Out of these studies, six delivered bright therapy, five delivered interpersonal and social rhythm therapy, two used blue-light blocking glasses, one delivered cognitive behavioural therapy for insomnia, one delivered total sleep deprivation, and four delivered bespoke combination treatments. Quality assessment produced mixed results but there was a general trend towards improvement in the last five years. More than half of the included studies (N=10, 52%) did not measure sleep or circadian rhythms despite being the principal target of the intervention. Overall, the evidence base for the effectiveness of the interventions was limited. There was a small number of trials for each intervention type, and a lack of consistency in treatment protocols and assessed outcomes. Meta-analysis was possible for the effect of bright light therapy on depression severity, revealing a medium-to-large post-treatment effect (Nc=6; g=-0.74 [95% CI=-1.05 to -0.42], p<0.001). Interpretation: There is a clear need for larger, adequately powered trials that incorporate comprehensive measures of sleep, circadian rhythms, mood, and functioning.