German school survey links cannabis use to social media and risk beliefs

BACKGROUND: Following Germany's partial cannabis legalization in April 2024, evidence on adolescent cannabis use risk factors is needed. Social media platforms represent understudied risk environments, and the comparative predictive value of risk perception versus prevention remains unclear. This study aimed to examine determinants of adolescent cannabis use in Germany, including platform-specific social media effects, nicotine advertising exposure, parental smoking, socioeconomic factors, and risk perception. METHODS: A cross-sectional survey of 829 students (age 11 to 19 years) from three secondary schools in northern Germany was conducted between April and July 2024. Cannabis use was measured on a 6-point ordinal scale. Associations were analyzed using ordinal cumulative link models and binary logistic regression, adjusted for age, gender, and school type. RESULTS: Lifetime cannabis use was reported by 3.8% of younger students (grades 5-7) and 20.3% of older students (grades 8-12), rising from 1.0% at age 13 to 39.1% at age 18. Social media use was strongly associated with cannabis consumption, particularly Instagram (OR = 4.3, 95% CI: 1.79-12.74, p = 0.003). Exposure to nicotine advertising on digital platforms increased the odds of cannabis use (OR = 2.02, 95% CI: 1.27-3.20, p = 0.003). Additional risk factors included parental smoking in the adolescent's presence (OR = 2.22-2.78, p = 0.001) and higher pocket money (> 50 €/month; OR = 3.0, p < 0.001). Perceived health risk of cannabis relative to cigarettes showed the strongest association with cannabis use (Nagelkerke R² = 0.20); adolescents rating cannabis as "much healthier" than cigarettes had substantially higher odds of cannabis use (OR = 22.5, 95% CI: 10.39-49.98, p < 0.001). School-based prevention showed no significant association (p = 0.70). Cross-substance analyses indicated that lower perceived cannabis risk relative to cigarettes was associated with higher nicotine use. CONCLUSIONS: Social media use and risk perception are key, modifiable factors of adolescent cannabis use. These findings may inform future prevention research focusing on credible risk communication and digital-platform contexts.