Methods: Local research teams in Mexico City, Guadalajara, and Monterrey recruited a stratified probability sample of 36 middle schools, 12 in each city. We randomized schools to three conditions: Culturally adapted kiR (kiR-A), Original kiR translated into Spanish (kiR-O), and a Control condition with treatment as usual. Regular teachers were trained to implement the kiR-A and kiR-O curricula to their students over a 3-4 month period. All students with parental consent completed pretest and posttest questionnaires during the 2017-2018 school year (n=5,524 at pretest). The relative effectiveness of kiR-A versus both kiR-O and Control was analyzed through baseline adjusted regression models in Mplus using FIML estimation to adjust for attrition (24%) and accounting for school-level random effects.
Results: Compared to kiR-O and to Control, kiR-A students reported relatively more use of the central kiR drug resistance strategies from pretest to post-test (Explain why you decline a drug offer, Leave the situation, Avoid drug offers) as well as closely related alternatives used in Mexico (Change the subject, Ignore the offer). KiR-A students also reported using an expanding repertoire of different drug resistance skills. In addition, kiR-A students reported relative declines in perpetrating bullying and aggression, compared to kiR-O and to Control conditions. Reductions in substance use at post-test were see among students who used alcohol or drugs more frequently at pretest. Among more frequent initial users, those in the Control condition reported relatively larger increases in the frequency of overall alcohol use and binge drinking, and those in kiR-O reported larger increases in the frequency of use of alcohol to intoxication, cigarette use, and hard drug use, compared to those in kiR-A.
Conclusions & Implications: The culturally adapted version of kiR for Mexico produced an expanding use of effective drug resistance strategies, less reliance on bullying and agression, and for those adolescents most at-risk, reduced substance use. These are all areas deliberately targeted in the cultural adaptation. Substance use and violence have the potential to negatively impact youth psychosocial development and integration into their families and communities. These findings suggest that integrating culture into substance use prevention programs can have immediate and positive effects.