Aims:
Schools represent a key setting for substance use prevention during adolescence. Multicomponent, school-based programs aim to influence knowledge, attitudes, and social norms simultaneously; however, evidence regarding their effectiveness remains inconsistent. This study aimed to assess the feasibility, acceptability, and indicative effects of a multicomponent, school-based intervention targeting tobacco and cannabinoid use among adolescents. Materials & Methods: This prospective observational study was implemented at a Hungarian secondary school. Anonymous, self-report questionnaires were administered before, during, and after the intervention (n=۴۱۷, n=۴۹۷, and n=۶۳۱, respectively). Outcome indicators included the lifetime and ۳۰-day prevalence of tobacco and cannabinoid use, knowledge, attitudes, and participation in individual program components. Findings: Lifetime
tobacco use increased from ۴۸% to ۵۶% and ۵۸%, while lifetime cannabinoid use increased from ۱۴% to ۱۸% and ۱۹% across the three waves; monthly use also increased for tobacco (۲۳%, ۲۵%, ۲۵%) and
cannabinoids (۶%, ۷%, ۸%), with no overall reduction over time. Participation averaged ۲.۲۲±۱.۴۹ program elements in Wave ۲ and ۲.۴۰±۱.۶۲ in Wave ۳. Peer-group activities and the prevention quiz were associated with lower cannabinoid experimentation (Fisher’s exact test, p<۰.۰۵; χ²(۱)=۴.۱۲, p<۰.۰۵), while poster and quiz participation was associated with
tobacco use or experimentation (χ²(۱)=۴.۲۰, ۶.۳۴, and ۵.۴۵; all p<۰.۰۵). Tobacco-related knowledge increased from ۸۳% to ۸۹% during the program but declined slightly to ۸۷% afterward, while protective attitudes returned to ۵۹%. Conclusion: A multicomponent, school-based prevention program is feasible and acceptable, reaches higher-risk adolescents, and warrants further rigorous evaluation despite not significantly reducing substance use prevalence.