Systematic Review and Meta-Analysis of the Prevalence of Substance Use Among Adolescents in South Africa.

Introduction: Substance use among young people is a growing public health concern in South Africa (SA), with implications for short- and long-term mental health, education and development. A lack of use data is among several challenges impeding progress to support young people. To address this gap, this study aimed to synthesise published prevalence data on substance use among adolescents under 19 years of age in Sa. Methods: 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 I(2) statistics and meta-regression. Results: Thirty publications met inclusion criteria, and these reported 202 prevalence estimates (n = 120,041, mean age 16.1 years). The most commonly reported substances used were alcohol (35.09%, 95% CI 23.83-48.30), tobacco (25.47%, 95% CI 14.56-33.01) and cannabis (10.47%, 95% CI 5.98-17.71) with lifetime prevalence of any substance use of 13.05%, 95% CI 9.65-17.42. Similarly, 12-month data indicated high exposure levels: alcohol 17.45% (95% CI 11.39-25.78), tobacco 11.57% (95% CI 8.92-14.88) and cannabis 6.66% (95% CI 4.82-9.13). However, substantial heterogeneity across studies was detected. Discussion And Conclusions: High exposure to substances in SA, especially alcohol, tobacco and cannabis, underscores the urgent need for nationally representative surveillance and evidence-based prevention efforts tailored to adolescents, to avoid progression of substance use into substance use disorder.