"But Others Do It!"

The authors examined the effects of perceived prevalence of drug use among same-age peers on adolescents' subsequent drug use. In 7th grade, participants estimated prevalence of alcohol and marijuana use among 7th-grade students in their school, reported own use of these drugs, receipt of offers to use these drugs, and frequency of contact with peers who use these drugs. In 8th grade, participants reported their frequency of alcohol and marijuana use. Although perceived prevalence of drug use predicted subsequent alcohol and marijuana use when controlling for actual prevalence, these effects disappeared once participants'prior levels of drug use and proximal peer contacts were considered. Implications of findings for intervention programs aiming solely to increase accuracy of perceived prevalence estimates are discussed.