Impact of a peer-led intervention on bullying prevalence and mental health outcomes among students in Ghanaian senior high schools

Background Bullying in schools remains a critical youth mental health priority in Ghana. While bullying occurs across all levels of education, its nature and intensity in senior high schools are more complex, placing a significant number of adolescents at risk of adverse mental health outcomes annually. This study aimed to evaluate the effectiveness of a peer-led intervention on bullying prevention and its effect on mental health outcomes among senior high school (SHS) students in Ghana. Method A one-group pretest-post-test quasi-experimental design was conducted in 12 SHSs across 6 regions of Ghana. The intervention involved the training and deployment of 30 students per school to sensitize peers and to implement various school-based activities that prevent bullying and promote mental health outcomes. Programme effectiveness was assessed among 4,046 and 4, 063 students at baseline and endline respectively using the Olweus Bullying Questionnaire and Beck Youth Inventory tools. Descriptive statistics, chi-square tests, tests of proportion differences, and logistic regression analyses were conducted at a 95% confidence level. Results Bullying victimisation decreased significantly from 76.0% at baseline to 44.6% at endline (95% CI: −33.4 to −29.4; p < 0.001). Self-concept scores improved from 85.2% to 86.9% (p = 0.027). Although anxiety prevalence declined from 16.4% to 14.9% and depression from 6.8% to 5.9%, neither change reached statistical significance. At baseline, students with high anxiety had significantly greater odds of bullying victimisation (aOR = 1.41; 95% CI: 1.13–1.75) but this association was no longer statistically significant at endline. Conclusion This study demonstrates that peer-led interventions in senior high schools significantly reduced bullying victimisation, and improved self-concept among students. A reduction in anxiety and depression was also observed although these changes did not reach statistical significance. Longitudinal studies and randomised controlled trials are recommended to strengthen the evidence for bullying prevention and mental health promotion in senior high school settings.