School Health Program Reduced Marijuana Use by 23% Among High School Students

Students in schools implementing the program had 11% lower odds of ever using marijuana (aOR=0.89, 95% CI 0.81-0.98) and 23% lower odds of current marijuana use (aOR=0.77, 95% CI 0.64-0.93). The program was also associated with reduced sexual risk behaviors and experience of violence.

Multilevel difference-in-differences analysis comparing 237 exposed schools (30,336 students) to 401 unexposed schools (34,502 students) using 2015 and 2017 Youth Risk Behavior Surveys. The program was a socio-ecological health initiative administered by local education agencies nationwide.

This is one of the largest evaluations of a school-based program that included cannabis as an outcome. The 23% reduction in current marijuana use demonstrates that comprehensive school health approaches can meaningfully affect adolescent substance use.

The program targeted multiple health behaviors simultaneously rather than focusing solely on substance use. The finding that a broad school health approach reduced marijuana use alongside sexual risk behaviors and violence suggests that shared risk factors can be addressed through comprehensive programming.

Quasi-experimental design (schools were selected by local agencies, not randomly assigned). The Youth Risk Behavior Survey is self-reported. Two-year comparison may not capture long-term trends. Schools that implemented the program may have been more motivated for health improvement.