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 over two days to implement the kiR-A and kiR-O curricula to their students over 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 Controls 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 Controls, 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 controls. The direction of relative changes in recent use of alcohol, cigarettes and marijuana showed more desirable trends for kiR-A than for kiR-O or controls, but these effects were non-significant.
Conclusions: The culturally adapted version of kiR for Mexico produced expanding use of effective drug resistance strategies and less reliance on bullying in the short-term, areas deliberately targeted in the cultural adaptation. Longer-term tests may be needed to show significant effects on substance use behaviors.