Background The correlation between depression and sleep quality is well established in adults, but similar evidence is lacking in adolescents.

Objective To study the sleep quality, the positive rate of depressive symptoms, and their correlation among middle school students in Shanghai, so as to provide a basis for providing mental health and sleep management to this group of students.

Methods From September to November 2020, using multi-stage stratified cluster random sampling method, a total of 7796 students from 32 middle schools in 16 districts of Shanghai were selected to conduct a questionnaire survey. The questionnaire for middle school students of the 2020 Shanghai Students’ Common Diseases and Health Influencing Factors Surveillance was used to collect students' demographic information, history of smoking, history of drinking, and history of chronic diseases; the Pittsburgh Sleep Quality Index was used to assess sleep quality; and the Center for Epidemiological Studies Depression Scale was used to evaluate depressive symptoms. χ² test was used to compare qualitative data between groups. Binary logistic regression was used to analyze the correlation between sleep quality and depressive symptoms among middle school students in Shanghai.

Results After excluding incomplete questionnaires, a total of 7160 valid questionnaires were collected. The average sleep time of middle school students in Shanghai was (7.54±1.15) h. Among them, 84.8% reported insufficient sleep time < 9 h, and only 15.2% reported sleep time ≥9 h. In addition, 9.2% of the students had poor sleep quality (Pittsburgh Sleep Quality Index ≥8 points). The sleep quality of urban students was worse than that of suburban students. The sleep quality of girls was worse than that of boys. The sleep quality of students in the third grade of middle school was worse than that of students in the first and second grades of middle school. Students with smoking history, drinking history, and chronic disease history had worse sleep quality than those without (P<0.05). The positive rate of depressive symptoms among middle school students in Shanghai was 22.2%, among which 7.0% reported possible depressive symptoms and 15.2% reported definite depressive symptoms. The positive rate of depressive symptoms in female students (26.1%) was higher than that in male students (18.5%); among different grades of middle school, the positive rate of depressive symptoms of the third grade middle school students was the highest (24.1%); the positive rates of depressive symptoms in students with smoking history, drinking history, and chronic disease history were higher than those without; the positive rate of depressive symptoms was higher in students with poor sleep quality (P<0.05). The results of logistic regression analysis indicated that the students with poor sleep quality showed higher risks of reporting depressive symptoms, and the OR (95%CI) was 17.064 (14.024-20.764).

Conclusion The positive rates of poor sleep quality and depressive symptoms of middle school students in Shanghai are high, and there is a significant correlation between these two indicators. For students’ mental health and sleep management, more attention should be paid to the quality in addition to the quantity of sleep.