Systematic review and meta-analysis of the prevalence of substance use among adolescents in South Africa

Background: Substance use among young people is a growing public health concern in South Africa (SA), with implications for short- and long-term mental health, and education and development. A lack of use data is amongst several challenges impeding progress to support young people. To address this gap, this study aimed to synthesize published prevalence data on substance use among adolescents under 19 years of age in SA. Methodology: We conducted a systematic review and meta-analysis following PRISMA guidelines. Searches were run across PubMed, PsycINFO, Web of Science and Scielo. Studies reporting original SA prevalence data in community- or school-based samples were included. The Joanna Briggs Institute checklist for prevalence studies was used to assess study quality. Meta-analyses were performed in R, using random effects models, and heterogeneity was assessed using I2 statistics and meta-regression. Results: Thirty studies met inclusion criteria, representing 202 prevalence estimates (n=120 041, mean age 12.09 -19 years old) across the nine provinces of the country. The most commonly reported substances used were alcohol (37%, 95%CI=30.36-48.39), tobacco (25.66% 95%CI=17.12-34.19), and cannabis (12.63% 95%CI=7.38-17.88) with lifetime prevalence of any substance use of 17.11% 95%CI=13.51-20.7239. Similarly, 12-month data indicated high exposure levels: alcohol 33.17% (95%CI=19.51-46.82), tobacco 15.82% (95%CI=8.73-22.90), and cannabis 8.27% 95%CI=3.96-12.57. However, substantial heterogeneity across studies was detected. Conclusion: High exposure to substances in South Africa, especially alcohol, tobacco, and cannabis, underscores the urgent need for nationally representative surveillance and evidence-based prevention efforts tailored to adolescents, particularly in early intervention to reduce progression of substance use to disorder.