Embargoed for release: Monday, December 8, 2025, 4:00 PM ET
Key points:
Children whose schools reopened during the COVID-19 pandemic had significantly decreased mental health diagnoses relative to children whose schools remained closed, according to a new study of schools across California. This included fewer diagnoses of depression, anxiety, and ADHD. Girls’ mental health benefited the most.
Mental health care spending decreased by up to 11% by the ninth month after a school’s reopening.
The study is among the largest and most data-rich examinations of how school closures impacted children’s mental health during the pandemic.
Boston, MA—Reopening schools during the COVID-19 pandemic was linked with significantly lower rates of mental health diagnoses among children, including anxiety, depression, and attention-deficit/hyperactivity disorder (ADHD), and a drop in related health care spending, according to a new study from researchers at Harvard T.H. Chan School of Public Health and colleagues. The benefits were especially pronounced among girls.
The study will be published Monday, Dec. 8, 2025, in Epidemiology.
“Our results provide solid evidence to parents, educators, and policymakers that in-person school plays a crucial role in kids’ wellbeing,” said senior author Rita Hamad, professor of social epidemiology and public policy. “The findings offer lessons for future public health emergencies and provide insight into why mental health worsened for children during the pandemic.”
Previous studies have established that youth mental health declined during the pandemic, and some additionally hinted at the mental health benefits of in-person school during this period. Most of those studies, however, relied on surveys and anecdotes from small study populations.
For this study, the researchers analyzed health diagnoses and spending data among 185,735 children, ages five to 18 years between March 2020 and June 2021, focusing on whether children received mental health care or filled a prescription for a mental health diagnosis such as anxiety, depression, or ADHD. These children lived in 24 counties and 224 school districts across California, where schools stayed closed longer than almost any other state and opened on a staggered basis, creating a natural experiment. The data was procured from the Healthcare Integrated Research Database, a large commercial administrative database with individual-level health insurance claims data, and administrative school-level data from the California Department of Education.
The study found that the proportion of children with a mental health diagnosis increased from 2.8% to 3.5% over the study period, but that children whose schools reopened had decreased mental health diagnoses relative to children whose schools remained closed. By the ninth month following a school reopening, children’s probability of being diagnosed with a mental health condition was reduced by 43% compared with the period before schools reopened. This included fewer diagnoses of depression, anxiety, and ADHD. Relatedly, health care spending associated with mental health diagnoses decreased. By the ninth month following a school’s reopening, non-drug medical spending decreased by 11%; spending on psychiatric drugs decreased by 8%; and spending on ADHD-specific drugs decreased by 5%. The study also found that girls’ mental health benefited more from school reopenings than boys’.
The researchers posited several potential reasons for why school closings may have impacted children’s mental health, including changes in social interaction; irregular sleep patterns; increased screen time; less balanced diets; learning difficulties; familial difficulties due to economic hardship or increased time spent at home together; and less access to mental health services normally available through school.
“As we consider future public health emergencies, this study suggests we need to prioritize safe school reopenings and ensure children have access to the social and emotional resources that schools provide,” Hamad said. “Policies should focus not only on infection control, but also on the mental wellbeing of children, recognizing that schools are a critical part of their support system.”
The researchers noted that the study population included only children in relatively higher-income areas in California, who were enrolled in commercial insurance and had relatively better access to health care. Further study is needed to assess the relationship between school reopening and mental health among marginalized groups, among whom effects may have been even greater.
Article information
“Effect of School Reopenings on Children’s Mental Health during COVID-19: Quasi- Experimental Evidence from California,” Pelin Ozluk, Jeff Romine, Gosia Sylwestrzak, Rita Hamad, Epidemiology, December 8, 2025, doi: 10.1097/EDE.0000000000001930
The study received funding from the National Institutes of Health (grant U01MH129968).
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Harvard T.H. Chan School of Public Health is a community of innovative scientists, practitioners, educators, and students dedicated to improving health and advancing equity so all people can thrive. We research the many factors influencing health and collaborate widely to translate those insights into policies, programs, and practices that prevent disease and promote well-being for people around the world. We also educate thousands of public health leaders a year through our degree programs, postdoctoral training, fellowships, and continuing education courses. Founded in 1913 as America’s first professional training program in public health, the School continues to have an extraordinary impact in fields ranging from infectious disease to environmental justice to health systems and beyond.
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