Purpose: Depression and anxiety are two highly prevalent mental disorders that commonly coexist. However, little is known about the association between sleep and comorbid depressive and anxiety symptoms (CDAS). Therefore, this study aims to explore the relationship between sleep duration, insomnia and CDAS.
Methods: This is a cross-sectional study of 22,004 community adults who participated in the China Multi-Ethnic Cohort (CMEC) study. Chinese version of Patient Health Questionnaire-2 and Generalized Anxiety Disorder-2 were used to screen CDAS in community adults. A positive score on each scale was considered indicative of CDAS. All participants received face-to-face interviews, medical examinations, and biochemical examinations to assess sleep duration and insomnia and collect covariates. The self-reported sleep duration was divided into three groups: < 7 hr, 7– 9 hr and > 9 hr groups. Logistic regression was used to analyze the association between sleep duration, insomnia and CDAS. A restricted cubic spline (RCS) was used to explore the dose–response relationship between sleep duration and CDAS. Stratified analysis based on gender and age was conducted.
Results: Overall, 2.8% (95% CI 2.6%~3.0%) of participants reported having CDAS. After adjusting the potential covariates, sleep duration < 7 hr (OR=1.635, 95% CI=1.335~2.004) was significantly associated with CDAS, compared with sleep 7– 9 hr. After RCS analysis, there was a nonlinear relationship between sleep duration and CDAS. The increase in the number of types of insomnia, the greater the likelihood of CDAS (p for trend< 0.05). In sensitivity analysis, it was found that the results were consistent with those of the main analysis. After stratification by gender and age, the association between sleep duration and CDAS was only observed in female and young and middle-aged adults, not in men and older adults.
Conclusion: Both insufficient sleep duration and insomnia are associated with a higher prevalence of CDAS in Chinese adults.

Keywords: sleep duration₁, insomnia₂, comorbid depressive and anxiety symptoms₃, adults₄, cross-sectional study₅