The associations between sleep duration, cognitive function, and depressive symptoms: An analysis of Chinese adolescents from China Family Panel Studies

The adverse impact of depressive symptoms on adolescents' physical and psychological health is becoming increasingly prominent. This study aims to examine the association between sleep duration, cognitive function, and depressive symptoms among Chinese adolescents. This study used data on a sample of 3724 adolescents collected from the China Family Panel Studies (CFPS). The multivariate logistic regression was conducted to estimate the association between sleep duration, cognitive function (measured by mathematics and vocabulary), and depressive symptoms among Chinese adolescents; the mediating effects of cognitive function were calculated by mediating model. The study found that approximately 6.49 % of Chinese adolescents had depressive symptoms, with an average CES-D8 score of 4.27 (SD: 3.11). Adolescents who reported a sleep duration of <6 h/night (OR = 2.34; 95 % CI = 1.30, 4.24) were at a higher risk of depressive symptoms, and the adolescents who had higher mathematics scores (>75 %) were more likely to be at a lower risk of depressive symptoms. Besides, the cognitive function competitively mediated the effect of sleep duration on depressive symptom (indirect effect = 0.043; 95 % CI = 0.023, 0.064). This is a cross-sectional study; all questions were self-reported; the sleep variable only included the sleep duration. Our study highlights that short sleep duration might increase the risk of depressive symptoms, and increasing cognitive function might reduce the occurrence of depressive symptoms in Chinese adolescents. The results displayed that sleep duration had a negatively direct effect on depressive symptoms, but the indirect effects of sleep duration on depressive symptoms via the cognitive function (i.e., mathematics and vocabulary tests) were significantly positive, indicating that the relationship between sleep duration and depressive symptoms was competitively mediated by cognitive function.