RESUMEN
BACKGROUND: Concerns about the rise in adolescent vaping and cannabis use suggest the need for effective substance use prevention programs. Botvin LifeSkills Training (LST) has a strong evidence base at the middle school level for preventing or reducing tobacco use and related problems. A high school (grades 9-10) version of the LST program was also developed and shows promising initial evidence for reducing tobacco use in a single pilot study. However, the high school version of LST has not been sufficiently tested in an experimental trial, despite being widely implemented in high schools across the U.S. This paper outlines the study protocol for a large-scale cluster randomized trial of Botvin High School LST, with objectives of documenting the design of prospective research and promoting transparency. METHODS: A total of 60 high schools in Colorado and Ohio were randomized to the 10-session, teacher-led intervention group (n = 33 schools) or business-as-usual control group (n = 27 schools). Across two cohorts of schools, 9th-grade students complete self-report surveys at pretest, immediate posttest, 1-year follow-up, and 21-month follow-up. Primary outcomes are tobacco (nicotine) use and cannabis use. Secondary outcomes are alcohol use, illicit drug use, psychosocial behaviors (e.g., violence and mental health), and academic achievement. Intent-to-treat analyses will use multilevel modeling to estimate intervention effects across assessment points. CONCLUSION: This independent evaluation will help to determine whether the intervention is appropriate for large-scale adoption. This trial is preregistered with the Open Science Framework (https://osf.io/dnz5q/).