Effect of School Reopenings on Children's Mental Health during COVID-19: Quasi-Experimental Evidence from California.

BACKGROUND: School closures during the COVID-19 pandemic disrupted children's education, socialization, and access to mental health resources, raising concerns about long-term effects on childrens' mental health. The objective was to evaluate impacts of pandemic-era school reopenings on children's mental health and healthcare expenditures. Variation in timing of school reopenings created a unique quasi-experiment. METHODS: We used difference-in-differences analysis to examine how staggered implementation of school reopenings affected diagnoses with depression, anxiety, and attention-deficit/hyperactivity disorder, and related healthcare spending among school-aged children during March 2020-June 2021 across 24 California counties. Data were drawn from medical claims from the second largest private health insurer in the state (N=185,735). RESULTS: School reopening was associated with a 1.2%-point drop in monthly prevalence of mental health diagnoses (95% CI: -1.59, -0.74), and a 10.6% (95%CI: -13.4%, -7.8%) drop in related healthcare spending. The mental health conditions that saw the largest differential between in-person and remote school districts were anxiety and depression. Effects were strongest among girls. CONCLUSIONS: In-person learning is an important component of children's mental health. These results are informative for future policymaking during public health crises, to balance infection risk with the need for socialization and other critical resources that schools provide to children.