Changes and relevant factors in depressive and anxiety symptoms among Chinese adolescents after the "Double Reduction" policy: A repeated cross-sectional survey with a nested longitudinal subsample

Background: The Chinese government has enacted the "Double Reduction" Policy, which aims to reduce students' academic burden and promote their mental health, but there is limited research examining the policy's impact on students' well-being. This study aims to evaluate changes in students' mental health problems before and after the "Double Reduction" Policy and explore relevant influential factors. Methods: A total of 101,976 elementary and junior high school students were recruited before the "Double Reduction" Policy, and 91,832 students were recruited one year later. Through data integration, a total of 36,637 students participated in both web-based surveys and provided complete data on all measures. Results: As a whole, we found that the prevalence of students' depression (12.1 % to 9.2 %) and anxiety (8.9 % to 6.2 %) tended to decline after the "Double Reduction" Policy. Attending private school, reduced homework, more extracurricular activities, more time with parents, reduced academic stress, and sleep duration >= 8 h/n were associated with the decrease in the likelihood of mental health problems in students. Female gender, negative life events, and negative impact of COVID-19 as risk factors for mental health. Conclusions: These findings indicated that the "Double Reduction" Policy has improved the well-being of Chinese students. Reducing students' homework burden and alleviating their academic pressure are beneficial for their mental health. Increasing time for extracurricular activities and interaction with parents, as well as ensuring sufficient sleep for students, are also effective ways to prevent the onset and exacerbation of mental health symptoms in adolescents.