Depression mediates the association of healthy sleep patterns with suicidal ideation among U.S. adults

Background: Sleep disturbances are common and strongly linked to depression and suicidal ideation, both of which are major public health concerns. However, evidence on whether depression mediates the association between overall sleep patterns and suicidal ideation remains limited. Methods: We conducted a cross-sectional analysis using data from 5,978 U.S. adults participating in the National Health and Nutrition Examination Survey. Participants were included if they completed the sleep, depression, and suicidal ideation assessments. A composite sleep score was constructed from four distinct sleep behaviors. Depression was defined as the Patient Health Questionnaire-9 (PHQ-9) score of ≥10, and suicidal ideation was assessed by the ninth PHQ-9 item (score 1-3). Logistic regression was used to evaluate associations between sleep score and depression/suicidal ideation, and mediation analysis tested the indirect effect of depression. Results: The mean age of participants was 45.00 years, and 52.85% were men. Higher sleep scores were linearly associated with lower odds of both depression and suicidal ideation (P for trend < 0.001). Compared with participants scoring 0-1, those scoring 4 had markedly reduced odds of depression (odds ratio [OR], 0.12; 95% confidence interval [CI], 0.06, 0.25) and suicidal ideation (OR, 0.20; 95% CI, 0.12, 0.36). Depression partially mediated the association between the healthy sleep score and suicidal ideation, accounting for 36.2% of the effect. Conclusions: Healthy sleep patterns are strongly associated with lower likelihoods of depression and suicidal ideation. These findings highlight the clinical importance of promoting healthy sleep behaviors and integrating depression screening and management into suicide prevention strategies.