Mental health before, during, and after COVID-19 (through 2025) in boys, girls, and gender-diverse youth

Background Adolescent mental health after the COVID-19 pandemic has been a major public health concern. Studies covering the post-pandemic period remain scarce and rarely include gender-diverse youth. We examined trends in mental health among cisgender, transgender, and nonbinary youth during the pandemic and through 2025. Methods Participants (N=636,201) were adolescents in grades 8-11 from the Finnish School Health Promotion study between 2019 and 2025, a repeated cross-sectional classroom survey. Validated questionnaires were used to assess clinical levels of depressive, generalized anxiety and social anxiety symptoms, as well as mental well-being. Results In 2025 there were 81,145 (48.6%) cisgender girls, 1137 (0.7%) transgender boys, 78,898 (47.2%) cisgender boys, 449 (0.3%) transgender girls, and 4658 (2.8%) nonbinary youth. Clinically significant depressive and generalized anxiety symptoms remained more prevalent in 2025 (reference) compared with pre-pandemic levels across all groups (ORs for 2019, 0.48-0.86; p<0.01). Compared with other groups, symptoms were most prevalent among transgender boys and nonbinary youth. Among cisgender youth, generalized anxiety symptoms increased across the post-pandemic period (ORs for 2021 and 2023, 0.81-0.95; p<0.0001). Nonbinary youth were the only group to show a recovery pattern in depressive, generalized anxiety, and social anxiety symptoms (ORs for 2021, 1.36-1.52; p<00001) and demonstrated improved mental well-being after the pandemic (beta for 2021, -0.68; p<0.0001). Conclusions The results indicate that the elevated levels of mental health problems among adolescents associated with the COVID-19 pandemic have not subsided. They also reveal persistent disparities by gender identity and call for targeted policy action.