Methods: Students in two middle schools in Guadalajara, Mexico were recruited and randomized into a treatment (N=226) and control (N=206) condition (e.g. those receiving keepin’ it REAL compared to those receiving no substance use prevention programming). Students (mean age = 13) in both conditions completed a pre-test prior to implementation, a short-term post-test after the last lesson was delivered, and a long-term post-test 12 months later. Substance use measures were 30-day amount and frequency of alcohol, cigarette, and marijuana use. Growth curve models with missing data imputation examined program effects on trajectories of substance use.
Results: Growth curve models indicated that over time the effects of keepin’ it REAL are gendered. Females in the treatment group drank alcohol significantly less frequently over time compared to females in the control school. Males in the treatment group, however, showed a relative reduction over time in the amount of marijuana used.
Conclusions: This pilot study provides support for the global applicability of efficacious substance use prevention programs originally developed in one country, but also the importance of assessing for cultural fit to achieve maximum efficacy. The results indicate that keepin’ it REAL can be an effective tool in teaching drug resistance strategies and reducing substance use among adolescents in a major urban area in Mexico. The findings also point to the possible impact of gendered cultural norms on the efficacy of prevention interventions in Mexico, and the need for these interventions to recognize gender differences in substance use patterns and their etiology. Although a more extensive cultural adaptation of keepin’ it REAL may be needed in Mexico to capture both male and female adolescents’ perspectives and reinforce cultural sources of resilience against substance use, the core components of keepin’ it REAL provides a promising foundation for creating an evidence-based substance use prevention curriculum for adolescents living in Mexico.