How Long Should We Sleep? Exploring the Relationship Between Sleep Duration and the Prevalence of Depression

The relationship between sleep duration and depression represents a critical public health concern. This study examined how weekday and weekend sleep durations are associated with depression prevalence among US adults. The primary research question was: What is the nature of this association across weekdays and weekends?

Data were drawn from the most recent pre-pandemic cycle of the National Health and Nutrition Examination Survey (NHANES; 2017-March 2020), including 4089 adults aged 20 years and older. Correlational and non-linear regression analyses were conducted to explore the associations between sleep duration and depression indicators. Analyses were also stratified by gender to investigate potential gender differences.

Spearman correlation and restricted cubic spline analysis indicated that weekend sleep duration was correlated with depression prevalence, but not with the total depression score or the annoyance of depression. Restricted cubic spline further analysis revealed a U-shaped association of sleep duration with the prevalence, total score, and annoyance of depression. The inflection points for depression prevalence were approximately 7.7 h for weekdays and 8.3 h for weekends. Better sleep durations were identified as 7.5-7.8 h on weekdays and 8.0-8.7 h on weekends, based on the expected odds ratios (ORs) with median sleep durations as the reference. Meanwhile, some gender differences were also observed.

This study supports and extends previous findings, confirming that both insufficient and excessive sleep are associated with higher depression prevalence. Sleep duration in the identified beneficial ranges (using median sleep duration as a reference) may help reduce the risk of depression, with slight variations by gender. Our findings further underscore the complex relationship between sleep and mental health and suggest the need to attend to intra-week variations in sleep behavior. These insights may inform the development of more refined and personalized mental health promotion strategies in the future.