Background: Chronotherapy (sleep deprivation, sleep phase shifting and/or the use of bright light) combines non-invasive and non-pharmacological interventions that may act rapidly against depressive symptoms. However, to date no meta-analysis has been conducted to examine their effectiveness.
Methods: We carried out meta-analysis of 16 studies (four randomised controlled trials and 12 open-label case series) with between-subject comparisons between experimental and control conditions for RCTs and within-subject comparisons between baseline and follow-up for all studies.
Results: Overall chronotherapy was generally superior to other therapies such as psychotherapy, antidepressants, exercise or light therapy alone after 5-7 days. For RCTs, chronotherapy was favoured (Hedge's g = 0.62, 95% CI 0.23-1.01) compared to control treatments such as antidepressants and exercise. 33.0% of patients were responders after 5-7 days in the chronotherapy group and 1.5% of patients in the control condition (OR = 7.58, 95% CI 2.03-28.28). For the case series, large effect sizes were found by 5-7 days (g = 1.78, 95% CI 1.49-2.07). In the case series, 61.6% of patients were classed as responders.
Limitations: The number of RCTs included in this meta-analysis was small, and the potential for risk of bias could not be ascertained accurately. One specific limitation is that studies nearly all included in-patients and the results may not be generalisable to out-patients, and nearly all the subjects lacked credibility ratings before receiving treatment.
Conclusions: Chronotherapy appears to be effective and well-tolerated in depressed patients. Nevertheless, further clinical and cost effectiveness studies are needed.
Keywords: Depression; chronotherapy; light therapy; meta-analysis; sleep deprivation.
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