Methods for Investigating Costs and Benefits of Prevention Interventions

Adolescent drug use is a major public health problem because of the proportion of the population using drugs and because of the multiple effects of adolescent drug use on adolescents, their families, and their communities. In 1993 an estimated 87 percent of high school seniors reported use of alcohol, 35 percent had used marijuana, and 6 percent had used cocaine sometime in their lifetime (Johnston et al. 1994). High school senior data are considered lower bound prevalence data because the sample does not include an estimated 20 percent who dropped out of school, a subset with higher rates of drug use than the students surveyed (Johnston et al. 1994). Particularly disturbing is the proportion of drug users with preadolescent onset of use, with 24 percent of students reporting that they used alcohol by sixth grade (Gleaton and Adams 1990).