Assessing a public health approach to delay onset and progression of adolescent substance use: Latent transition and log-linear analyses of longitudinal family preventive intervention outcomes

This study examined the effects of the Iowa Strengthening Families Program (ISFP) and the Preparing for the Drug-Free Years program (PDFY) on young ad olescent transitions from nonuse of substances to initiation and progressio n of substance use. Analyses incorporated 3 waves of data collected over a 2.5-year period from 329 rural young adolescents. Outcomes were analyzed by using log-linear models that incorporated substance use status frequencies derived from latent transition analyses. Effects on delayed substance use initiation were shown for both the ISFP and the PDFY at a 2-year follow-up. Also at this follow-up, the PDFY showed effects on delayed progression of use among those previously reporting initiation.