ABSTRACT Objectives: To provide first comprehensive estimates of the prevalence of psychoactive substances: alcohol, cigarettes and marijuana and their associated factors among school-going adolescents in 25 African countries, and thereby contribute to the evidence base of substance use in Africa. Methods: We use the publicly available Global School-Based Health Survey (GSHS) data from 25 African countries collected between 2003 and 2017. We used descriptive statistics to estimate the prevalence of alcohol, cigarette, and marijuana use as well as their dual use among adolescents aged 11-16 years. Additionally, we used logistic regressions to model factors associated with the use of each substance, with adjusted odds ratios (ORs) and their 95% confidence intervals (CIs) as the measures of association. Results: The prevalence of alcohol use among African adolescents was 10.6% [95% CI = 9.6, 11.8], that for cigarette smoking was 6.9% [95% CI: 6.1, 7.8], and it was 3.8% [95% CI: 3.2, 4.4] for marijuana. The prevalence of dual use of alcohol and cigarettes was 1.5% [95% CI: 1.2, 1.9], that of alcohol and marijuana was 0.9% [95% CI: 0.7, 1.1], and it was 0.8% [95% CI: 0.6, 1.0] for cigarettes and marijuana. The prevalence of cigarette smoking was significantly higher among boys than girls, but that of alcohol and marijuana was insignificant. The use of alcohol, cigarettes, or marijuana was associated with the West African region, higher-income country group, having parents that smoke any tobacco products, being bullied, missing classes without permission, and experiencing sadness and hopelessness in the previous month were positively associated with being a current user of these products. Conclusions: Africa should invest in data collection on substance use among adolescents who are in and out of school. At both primary and secondary school levels, African countries should develop mentorship and other interventions that fuel positivity and discourage bad practices among students to ultimately reduce substance use.

The authors have declared no competing interest.

This work was supported by the Bill & Melinda Gates Foundation (INV-048743).

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