• Children who returned to in-person school during the COVID-19 pandemic were much less likely to receive mental health diagnoses than children whose schools stayed closed. Reductions were seen in anxiety, depression, and ADHD, and girls experienced the greatest improvements.
• Mental health care spending fell notably after schools reopened, reaching an 11 percent decrease by the ninth month.
• This research represents one of the largest and most comprehensive analyses to date on how pandemic school closures affected children’s mental health.

School Reopening During COVID Linked to Better Mental Health for Children

A new study from Harvard T.H. Chan School of Public Health and collaborating institutions reports that children experienced far fewer mental health diagnoses when their schools reopened during the COVID-19 pandemic. The reductions were seen across conditions such as anxiety, depression, and attention-deficit/hyperactivity disorder (ADHD). Health care spending connected to these diagnoses also declined, and girls showed the strongest improvements.

The study was published on 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’ well-being,” 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.”

Background on Youth Mental Health During the Pandemic

Earlier research consistently showed that children and teens struggled emotionally during COVID-19. Some studies suggested that returning to classrooms offered important support, but many of those investigations relied on small samples or self-reported experiences rather than comprehensive data.

To produce a more detailed picture, the research team examined health diagnoses and spending information for 185,735 children between the ages of five and 18 years from March 2020 through June 2021. The dataset indicated whether a child received mental health treatment or filled a prescription related to anxiety, depression, or ADHD. Participants lived in 24 counties and 224 school districts across California, a state where school closures lasted longer than in most of the country and reopening timelines varied widely. These differences created a natural opportunity to compare outcomes. Data came from the Healthcare Integrated Research Database, which includes individual-level commercial insurance claims, along with school-level administrative data from the California Department of Education.

Large Reductions in Diagnoses and Spending After Reopening

The study documented an overall rise in mental health diagnoses during the pandemic, increasing from 2.8% to 3.5%. However, children who returned to in-person school were substantially less likely to receive new diagnoses than peers whose schools stayed closed. By the ninth month after reopening, the chance of being diagnosed with a mental health condition had dropped by 43% compared with the period before reopening. This trend included fewer cases of anxiety, depression, and ADHD.

Health care spending reflected a similar pattern. Nine months after schools reopened, non-drug medical spending related to mental health was 11% lower, spending on psychiatric medications was 8% lower, and spending on ADHD-specific medications was 5% lower. Girls saw greater improvements than boys over the same period.

How School Closures May Have Affected Children

The research team outlined several possible reasons for the mental health challenges children experienced while schools were closed. These included limited social interaction, disrupted sleep routines, more screen time, poorer dietary patterns, academic struggles, family stress linked to economic hardship or increased time at home, and reduced access to school-based mental health services.

“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.”

Study Limitations and Future Directions

The authors noted that the study focused on children living in relatively higher-income areas in California who were enrolled in commercial insurance plans, meaning they generally had better access to health care. More research is needed to explore how school reopening influenced children in marginalized communities, where the impact may have been even more significant.

The study received funding from the National Institutes of Health (grant U01MH129968).