Alcohol emerges as primary gateway to adolescent substance use in Cameroon

Psychoactive substance use among adolescents represents a growing public health concern in sub-Saharan Africa. This study examined alcohol and illegal psychoactive substance use among secondary school adolescents in Yaoundé, Cameroon, with particular attention to associated factors, including family relationships. A school-based cross-sectional study was conducted among adolescents enrolled in Forms 3 to 5 in three secondary schools in Yaoundé. Data were collected using a self-administered questionnaire. Quantitative analyses estimated 12-month prevalence and associated factors using robust Poisson regression for alcohol use and complementary log-log regression for illegal psychoactive substance use, complemented by bootstrap resampling and Firth's penalised regression to assess robustness in a rare-event context. Qualitative open-ended responses were analysed using thematic and lexical co-occurrence approaches (Jaccard C and T coefficients) to explore adolescents' representations of substances and perceived consequences. A total of 352 adolescents were included (54.3% girls). The median age was 15 years (IQR: 14-17; observed range: 12-20). The 12-month prevalence of alcohol use was 32.7% (95% CI: 27.8-37.8), while 3.7% (95% CI: 2.0-6.2) reported illegal psychoactive substance use. Marijuana and cocaine emerged as the most salient illicit substances within adolescents' cognitive representations, forming the strongest co-occurrence pattern (Jaccard C = 0.24; T = 0.389), while other substances such as tramadol, heroin, tobacco, and alcohol were mentioned less prominently. Perceived consequences were predominantly negative, encompassing neuropsychological, somatic, behavioural, and social effects, although limited positive representations persisted. Multivariable analyses showed that alcohol use was independently associated with increasing age, availability of drugs around the home, and illegal substance use. When illegal psychoactive substance use was the outcome, alcohol use was inversely associated. Family relationship variables were not independently associated with either outcome after adjustment. These findings underscore the central and asymmetric role of alcohol use in adolescent substance involvement. In parallel, they indicate that alcohol use among school-going adolescents is more strongly influenced by age and environmental exposure than by family relationship factors. They support multi-level prevention strategies focusing on early school-based psychoeducation, regulation of alcohol availability in home and community settings, and longitudinal research to clarify substance-use trajectories.