The Mental Health Costs of Shadow Education: The Duration of Shadow Education and Its Depressive Effects on Chinese Adolescents.

Shadow education refers to supplementary educational activities outside of the formal school system, typically provided by private institutions to enhance students' academic performance. This phenomenon has become increasingly prominent worldwide, drawing significant attention from both scholars and the public. While shadow education is often associated with improved academic outcomes, its potential mental health implications for adolescents remain underexplored. Based on four large-scale surveys conducted in China from 2016 to 2022, this study examines the association between the duration of shadow education and adolescent depressive symptoms, with particular attention being paid to differences across family backgrounds and policy environments. Utilizing multilevel regression models that incorporate individual, family, and community factors, as well as inverse probability weighting regression adjustment and sensitivity analyses, this study yields three main findings. First, the relationship between shadow education duration and adolescent depressive symptoms demonstrates a U-shaped pattern: moderate engagement is associated with lower depressive symptoms, while both limited and excessive participation are linked to higher symptom levels. Second, adolescents from higher-income families are more likely to maintain shadow education participation within an optimal range and report fewer depressive symptoms. Third, following the implementation of regulatory policies on shadow education in China after 2021, the duration of shadow education among adolescents has generally shifted toward a more balanced level, accompanied by a decrease in depressive symptoms. These results underscore the need to consider the nonlinear mental health effects of shadow education in both research and policymaking. In particular, contextual factors, such as socioeconomic background and policy interventions, should be taken into account when formulating and regulating supplementary educational activities. By addressing these dimensions, policymakers can better balance the academic benefits of shadow education with its potential risks for adolescent mental health.