Pathways to Positively Altered Developmental Trajectories Through Young Adulthood: Universal Substance Misuse Preventive Interventions

INTRODUCTION

Emerging research suggests brief universal interventions focused on the prevention of substance misuse can positively alter developmental trajectories through young adulthood.  Further research addressing this prospect is warranted, along with study of: (1) primary outcome mediators; (2) risk-related moderation of outcomes; and (3) crossover effects on related but non-targeted outcomes. Data from 2 RCTs testing family-focused universal interventions (stand alone and in combination with school-based intervention) were analyzed.

METHOD

In Study 1, 6th graders in 22 rural schools were assigned to an intervention condition (Iowa Strengthening Families Program [ISFP]—N=238) and a control condition (N=208). ISFP consists of 7 sessions for parents and youth designed to enhance skills to prevent youth substance misuse. Self-report questionnaires provided data from pretest through young adulthood (age 21; N=331). Measures included substance misuse and related outcomes (e.g., offending behaviors, health-risking sexual behaviors/STIs, physical/mental health). In Study 2, 7^th graders in 24 schools were assigned to a control condition or to an intervention condition combining a school-based program (Life-Skills Training) and a revised ISFP (Strengthening Families Program: For Parents and Youth 10-14). Students were followed through age 21 (N=745). Measures corresponded to those in Study 1. A range of analyses were employed, including SEM conducted with MPlus 6.1 (using the MLR estimator and FIML to address missing data).

RESULTS

Analyses supported the alteration of substance-related developmental trajectories in both Studies 1 and 2. Further, Study 1 showed that effects on young adult substance misuse were primarily indirect, via reduced exposure to substance misuse opportunities and reduced adolescent substance initiation. Findings were replicated in Study 2. Study 1 showed no risk-related moderation of intervention effects on substance misuse outcomes; it was, however, in evidence in Study 2, with stronger effects found for the higher-risk subgroup. Finally, crossover effects during young adulthood were found across both studies, including positive effects on non-targeted prescription drug misuse; offending behaviors, health-risking sexual behaviors/STIs, and physical/mental health.

CONCLUSIONS

Participation in preventive interventions during early adolescence can alter trajectories of substance misuse during adolescence; this, in turn, can positively affect a wide range of outcomes during young adulthood. In addition, universal intervention effects can be stronger for those at higher risk during early adolescence. Overall, findings highlight the potential public health benefits of developmentally well-timed universal preventive interventions.