Background Mental health challenges faced by young people are increasing. Women and girls experience higher levels of internalised mental illness, such as depression and anxiety. This may be because of biological development and/or social risks. Schools could support good mental health and detect areas for intervention. Moreover, aspects of the school environment, school culture, and levels of connection or belonging that students feel towards their school can influence students’ overall mental health and well-being. The aim of this study was to explore the prevalence of mental health outcomes and school connectedness among secondary school students, by gender, in the South West of England.

Methods This quantitative prevalence analysis used self-report questionnaire data from the South West – School Health Research Network (SW-SHRN). 5193 Year 8 and Year 10 students (aged between 11 and 14) were recruited from 18 schools in 7 local authorities. Proportions and associated 95% Confidence Intervals (CIs) were calculated for all outcomes and gender groups. Using the ‘survey’ package in R (Version 4.1.1), school level clustering and appropriate weighting based on school level response rates were applied.

Results Students were predominantly white (86.1%), the largest proportion (30.9%) came from the least deprived quintile, compared to 11.1% from the most deprived quintile. Slightly more students identified as male (51.4%), while 45.5% identified as female, and 3.1% neither. Across all mental health, well-being, and school connectedness measures girls and those that did not identify with either gender fared worse than boys. This difference was most notable for severe depression, with 72.6% (CI: 64.81–80.35) of students who identify as neither and 47.5% (CI: 44.56–50.52) of girls reporting severe depression, compared to 17.8% (CI: 15.21–20.29) of boys. Similarly, for poor well-being, girls (27.6% (CI: 24.61–30.61)) and those that identified as neither gender (50.2% (CI: 42.21–58.22)) had a higher prevalence than boys (12% (CI: 10.23–13.76)). Among students that identified as neither gender 81.1% (CI: 70.84–91.39) reported that they did not feel they belonged in their school, compared a lower proportion of girls (60.4% (CI: 54.74–66.13)) and boys (43.4% (CI: 37.86–48.83).

Conclusion There was a large gender gap in the mental health challenges faced by young people, not just between girls and boys, but importantly between students who identify as neither girl nor boy. These findings also demonstrate important gender differences in how students perceive their school and their level of connection to their school and highlight important areas for future interventions in schools.