Russian adolescent mental health in 2002, 2015 and during the COVID-19 pandemic in 2021.

These results suggest that the mental health of Russian adolescent girls has worsened in the 21st century; the gender gap in mental health has widened; the gender gap in alcohol use was reversed in 2021. The findings highlight the need for research into gender-specific factors and for effective interventions. The lack of changes in Russian adolescent mental health and substance use from 2015 to during the pandemic in 2021 suggests successful coping; however, more research is needed.