Sleep patterns and their association with depression and behavior problems among Chinese adolescents in different grades

We aimed to examine sleep patterns and their association with depression and behavior problems among Chinese adolescents in different grades. A cross-sectional study was conducted in 10 cities of mainland China. A total of 8,998 Chinese adolescents (49.3% males) aged 9-20 years completed a self-administered questionnaire that included questions on sleep patterns, depressive symptoms, behavior problems, and demographic characteristics. The percentage of adolescents who slept less than 7 hr on weekdays increased with grade, while the percentage of adolescents who slept less than 7 hr on weekends remained the same. The gap in sleep length between weekdays and weekends increased from 0.6 hr in grade 5 to 2.3 hr in Grade 12. The regression analysis showed that poor sleep habits were linked to greater emotional and behavioral problems. The associations of sleep length with those problems differed by symptom and grade. Sleeping less related to depression in all grades. More behavior problems were observed in primary school students who had less sleep and in senior high school students who had more sleep than their peers. The preference for going to bed late stably related to both adolescent depression and behavior problems in all grades, although it posed a greater risk for students in higher grades.