Cannabis use in sub-Saharan Africa: A systematic review and meta-analysis

The most available data on the prevalence of cannabis use come from population surveys conducted in high-income countries in North America, Oceania and Europe. Less is known about the prevalence of cannabis use in Africa. This systematic review aimed to summarize general population-level cannabis use in sub-Saharan Africa since 2010.

A comprehensive search was conducted in PubMed, EMBASE, PsycINFO and AJOL databases in addition to Global Health Data Exchange and grey literature without language restriction. Search terms related to 'substance', 'Substance-Related Disorders' and 'Prevalence' and 'Africa South of the Sahara' were used. Studies that reported cannabis use in the general population were selected, while studies from clinical populations and high-risk groups were excluded. Prevalence data on cannabis use in the general population of adolescents (10-17 years) and adults (≥ 18 years) in sub-Saharan Africa were extracted.

The study included 53 studies for the quantitative meta-analysis and included 13 239 participants. Among adolescents, the life-time, 12-month and 6-month prevalence of cannabis use were 7.9% [95% confidence interval (CI) = 5.4-10.9%], 5.2% (95% CI = 1.7-10.3%) and 4.5% (95% CI = 3.3-5.8%), respectively. The corresponding life-time, 12-month and 6-month prevalence of cannabis use among adults were 12.6% (95% CI = 6.1-21.2%), 2.2% (95% CI = 1.7-2.7%, with data only available from Tanzania and Uganda) and 4.7% (95% CI = 3.3-6.4%), respectively. The male-to-female life-time cannabis use relative risk was 1.90 (95% CI = 1.25-2.98) among adolescents and 1.67 (CI = 0.63-4.39) among adults.

Life-time cannabis use prevalence in sub-Saharan Africa appears to be approximately 12% for adults and just under 8% for adolescents.