Long Sleep Duration, Cognitive Performance, and the Moderating Role of Depression: A Cross-Sectional Analysis in the Framingham Heart Study

ABSTRACT INTRODUCTION We investigated whether depression modified the associations between sleep duration and cognitive performance. METHODS Multivariable linear regression models examined the associations between sleep duration and cognition in 1,853 dementia- and stroke-free participants from the Framingham Heart Study. Participants were categorized in four groups: no depressive symptoms, no antidepressants; depressive symptoms without antidepressants use; antidepressant use without depressive symptoms; both depressive symptoms and antidepressant use. RESULTS Long sleep was associated with reduced overall cognitive function. Strong associations between sleep duration and cognitive performance were found in individuals with depressive symptoms, regardless of antidepressant use. Weaker but significant effects were observed in those without depressive symptoms. No significant associations were observed in participants using antidepressants without depressive symptoms. DISCUSSION These findings provide new evidence that sleep duration may be a modifiable risk factor for cognitive decline, particularly in individuals with depressive symptoms. Future research should elucidate underlying mechanisms and temporal relationships. RESEARCH IN CONTEXT Systematic review: We conducted a systematic search on PubMed and Google Scholar for peer-reviewed articles using keyword combinations related to sleep, cognition, and depression. Existing evidence reveals mixed findings on the relationship between sleep duration and cognition, with limited studies examining the role of depression on this association. Interpretation: We observed that only long sleep duration (≥9h) was associated with poorer global cognition, executive function, visuospatial memory, and verbal learning/memory. Depression moderated this association, showing stronger negative effects of long sleep on cognition in individuals with depressive symptoms, regardless of antidepressant use. This suggests that long sleep duration may serve as an early indicator or risk factor for cognitive decline in those with depressive symptoms. Future directions: Longitudinal studies with objective and subjective sleep assessments across diverse populations are needed to clarify how depression and its treatment influence the relationship between sleep duration and cognitive decline and support clinical strategies. HIGHLIGHTS Sleeping ≥ 9hours/night was associated with worse cognitive performance. This association was stronger among those with depression. Long sleepers were more likely to report symptoms of depression. Sleep may be a modifiable risk for cognitive decline in people with depression.