Efficacy of the Mexican version of the keepin’ it REAL school-based prevention program in addressing multi-substance use from early to mid-adolescence

Abstract

Purpose

We tested effects of a culturally adapted version of the Keepin’ it REAL (KiR) prevention program on longitudinal patterns of polysubstance use among Mexican adolescents.

Methods

A sample of 36 public middle schools in Mexico City, Guadalajara and Monterrey was randomized to: culturally adapted KiR, original KiR translated into Spanish, and treatment-as-usual controls. Regular teachers with training in KiR implemented curricula over 3–4 months. Seventh-grade students with parental consent completed pretests in Fall 2017 (n = 5522), and three posttests: later in 7th grade, in 8th and 9th grade. We analyzed patterns of recent use of five substances (alcohol, tobacco, inhalants, marijuana, other illicit drugs) and the efficacy of the two KiR versions using repeated measures latent class analysis (RM-LCA).

Results

RM-LCA produced six classes: (A) non-use of substances across all time points; (B) initiating only licit substances; (C) initiating both licit and illicit substances; (D) declining use; (E) initiating inhalant and alcohol use; and (F) persisting polysubstance use. Adapted KiR students were more likely than controls to report declining substance use (class D), and less likely to initiate use (C and E). Adapted KiR students were overrepresented among those engaging in persisting polysubstance use, largely due to baseline differences. Un-adapted KiR showed no differences with controls.

Conclusions

Culturally adapted KiR for Mexico curbed initiation of especially harmful forms of illicit drug use, and prompted declines among those already engaging in use. Lack of evidence of efficacy of the un-adapted version of KiR suggests the need for cultural adaptation of efficacious interventions for new target populations.