Across 25 African countries, marijuana use prevalence was 3.4% among school-going adolescents, with bullying, school absenteeism, and sadness consistently linked to substance use.
Global health researchers, school-based prevention program developers, policymakers in African nations.
3.4% marijuana prevalence across 25 African countries
What the researchers found
Among school-going adolescents (ages 11-16) across 25 African countries, marijuana use prevalence was 3.4% (95% CI 2.7-4.2%). Unlike cigarette smoking, marijuana use did not differ significantly by sex. Parental tobacco use, being bullied, missing school without permission, and experiencing sadness and hopelessness were positively associated with being a current user regardless of substance type.
Why it matters
This is one of the largest studies of adolescent substance use across the African continent, revealing that marijuana use among school-going youth is lower than alcohol (9.5%) and cigarettes (6.2%) but shares the same risk factors. The consistent role of mental health factors like bullying and sadness across all substance types suggests integrated prevention approaches could be effective.
The numbers in context
Marijuana prevalence: 3.4% (95% CI 2.7-4.2%). Alcohol: 9.5%. Cigarettes: 6.2%. Dual use alcohol + marijuana: 2.0%. Cigarettes + marijuana: 1.4%. No significant sex difference for marijuana. 25 countries included.
How the study worked
Pooled cross-sectional analysis of the Global School-based Health Survey (GSHS) from 25 African countries (2003-2017). Descriptive statistics estimated prevalence. Logistic regressions modeled factors associated with alcohol, cigarette, and marijuana use with adjusted odds ratios. Dual-use patterns were also examined.
What this study cannot tell us
Cross-sectional design cannot establish causal direction. Self-reported substance use may underestimate true prevalence. Data span 2003-2017, so current patterns may differ. School-based survey excludes out-of-school adolescents who may have higher use rates.
How to read the evidence
Moderate: large multinational dataset with standardized methodology, though cross-sectional design and self-reported data limit causal inference.
When this study was published
2025 study (data from 2003-2017)
The bigger picture
Substance use research in Africa has historically received less attention than in North America or Europe. These findings show that while prevalence rates differ, the underlying risk factors for adolescent substance use are remarkably consistent globally, suggesting universal prevention strategies targeting bullying, school engagement, and emotional wellbeing could reduce use.
Questions still open
- Have prevalence rates changed since 2017, particularly as cannabis policy evolves in some African nations? Would including out-of-school youth significantly change the estimates? Are bullying and mental health prevention programs effective in reducing substance use in African contexts?
Common questions
Is marijuana use common among African teenagers?
What predicts which teens will use marijuana?
Read the original research
What are the factors associated with alcohol, cigarette and marijuana use among adolescents in Africa? Evidence from the Global School-based Health Survey.
BMJ open, 15(7), e089096
Citation
Pokothoane, Retselisitsoe; Argefa, Terefe Gelibo; Tsague, Josiane Djiofack; Mdege, Noreen Dadirai. (2025). What are the factors associated with alcohol, cigarette and marijuana use among adolescents in Africa? Evidence from the Global School-based Health Survey.. BMJ open, 15(7), e089096. https://doi.org/10.1136/bmjopen-2024-089096
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