PROSPER community-university partnership delivery system effects on substance misuse through 6 1/2years past baseline from a cluster randomized controlled intervention trial

Objective: To examine the effects of a delivery system for evidence-based preventive interventions through 12th grade, 6.5. years past baseline. Method: A cohort sequential design included 28 public school districts randomly assigned to the partnership delivery system or usual-programming conditions. At baseline, 11,960 students participated. Partnerships supported community teams that implemented a family-focused intervention in 6th grade and a school-based intervention in 7th grade. Outcome measures included lifetime, current misuse, and frequencies of misuse, for a range of substances. Intent-to-treat, multilevel analyses of covariance of point-in-time misuse and analyses of growth in misuse were conducted. Results: Results showed significantly lower substance misuse in the intervention group at one or both time points for most outcomes, with relative reduction rates of up to 31.4%. There was significantly slower growth in misuse in the intervention group for 8 of the 10 outcomes. In addition, risk moderation results indicated that there were significantly greater intervention benefits for higher- versus lower-risk youth, for the misuse of 6 of the 10 substances at 11th grade, illicit substances at 12th grade, and growth in the misuse of illicit substances. Conclusion: Partnership-based delivery systems for brief universal interventions have potential for public health impact by reducing substance misuse among youth, particularly higher-risk youth.