One-year follow-up evaluation of Project Towards No Drug Abuse (TND-4)

This paper describes the one-year outcomes of the fourth experimental trial of Project Towards No Drug Abuse. Two theoretical content components of the program were examined to increase our understanding of the relative contribution of each to the effectiveness of the program.

High schools in Southern California (n=18) were randomly assigned to one of three conditions: cognitive perception information curriculum, cognitive perception information+behavioral skills curriculum, or standard care (control). The curricula were delivered to high school students (n=2734) by project health educators and regular classroom teachers. Program effectiveness was assessed with both dichotomous and continuous measures of 30-day substance use at baseline and one-year follow-up.

Across all program schools, the two different curricula failed to significantly reduce dichotomous measures of substance use (cigarette, alcohol, marijuana, and hard drugs) at one-year follow-up. Both curricula exerted an effect only on the continuous measure of hard drug use, indicating a 42% (p=0.02) reduction in the number of times hard drugs were used in the last 30 days in the program groups relative to the control.

The lack of main effects of the program on dichotomous outcomes was contrary to previous studies. An effect on an ordinal count measure of hard drug use among both intervention conditions replicates previous work and suggests that this program effect may have been due to changes in cognitive misperception of drug use rather than behavioral skill.