Evaluative Evidence of Prevention Programs

School-Based Programs

The majority of drug prevention programs are conducted in schools as universal prevention approaches (i.e., administered to all students). These programs have also been the most researched in the drug prevention field. Overall, universal school-based programs have a small, but significant impact on drug use in both the short and long term compared to usual curricula programs, though effects tend to decrease over time with small to negligible effects often reported after two to three years. Research also suggests these programs have a greater impact on delaying the initiation of substance use than on the severity of use.

Features of effective school-based programs identified in reviews of the literature include: theory-driven interventions targeting specific risk/protective factors, interventions matched to the population of interest (e.g., developmentally and culturally appropriate), more intense and interactive programs (e.g., multiple sessions, teacher-led discussions), interventions targeting social influence factors (e.g., identifying sources of social influence, social resistance skills training), competency enhancement skills training (e.g., problem-solving, coping, social skills training), providing accurate information about drug use norms (e.g., countering perceptions that drug use is common), providing adequate training for providers to ensure adherence and competence in delivery, and smaller programs (large-scale programs tend to have smaller effects). There is also some evidence suggesting that programs may be more effective when led by a mental health practitioner, followed by peers, and finally teachers. In contrast, knowledge-only programs that focus solely on information dissemination and affective-only programs targeting factors such as self esteem and personal insight tend to have no impact on drug use rates compared to usual curricula.

The relatively small effects observed in universal programs, as well as the tendency to have less of an impact on severity of use, suggests the need for selective and indicated programs targeting at-risk students. These programs may serve to produce larger effects and reach those who would benefit most from prevention. However, there has been much less research on prevention programs targeting specific at-risk students and the evidence tends to be relatively mixed, with some studies finding positive effects and others finding no effect.

School-based prevention programs appear to be effective in both rural and urban populations and across ethnic groups. It is unclear whether effects may differ across genders as gender effects are rarely analyzed. Some studies have found differences by gender, suggesting the potential need for gender-specific programs targeting relevant risk/resilience factors.

...