Assessment of club patrons' alcohol and drug use: the use of biological markers.

Background: Young adulthood (ages 18-25 years) represents a time when high-risk behaviors, including alcohol and drug use, peak. Electronic music dance events (EMDEs) featured at clubs provide an ecologic niche for these high-risk behaviors.

Purpose: This paper examines the prevalence of alcohol and drug use among EMDE patrons.

Group influences on individuals' drinking and other drug use at clubs.

Objective: This article examines effects of the social group on individual alcohol and drug use upon entry and exit from the club. Based on collected biological measurements of alcohol and other drug use, this study explores whether social group indicators (e.g.