Napping and psychiatric disorders: A systematic review

Napping is associated with adverse health outcomes in healthy adults. Given limited evidence in psychiatric disorders, this PRISMA-compliant review examined napping across various conditions, including studies on prevalence or clinically relevant outcomes related to disease course. Among the 8275 records identified from PubMed, Web of Science, and Cochrane Library, 40 were included. Risk of bias was assessed using the Newcastle-Ottawa Scale, RoB 2.0, and ROBINS-I tools, by study design. Most studies concerned patients with depressive disorders, who often nap more frequently and longer than controls, with plausible differential impact across subpopulations. In some, like pregnant women, napping may represent a risk factor; in others, a negative prognostic marker. Fewer studies suggest napping benefits mood, well-being and memory. In bipolar disorder, napping appears prevalent and may increase the risk of depressive symptoms. Research on schizophrenia spectrum and anxiety disorders research is contradictory but generally shows higher napping prevalence versus controls, and links napping to increased anxiety risk in elderlies. Conversely, napping does not appear specifically associated with eating or neurodevelopmental disorders, although data on the latter remain scarce in adults. Overall, daytime napping is prevalent in most psychiatric disorders and may represent a risk and/or prognostic factor, deserving systematic clinical assessment.