Fifty-seven youth, between the ages of 15 and 19, were recruited for the study in 1998. They included recreational and problematic drug users as well as nonusers. Subsequent interviews and focus groups were conducted with 42 of the initial participants in 2001. The data obtained pertained to the youths' accounts of their drug-taking events, routines, and practices across time. The data reveal the complex social interactions linked to drug pathways. Analyses of change in drug-use behavior over the study period showed that drug pathways evolve in association with changing perceptions of safety and risk in drug use. Responses to perceptions of risk within the youths' drug-using contexts were linked to situational changes over time. Thus, the youth "scripted" risk based on accumulated experience. The type of decisionmaking and the factors that influenced the youths' decisions regarding drug-use risk were flexible and dependent on social and economic conditions. Based on these findings, the author argues that models of risk for drug use that rely on individual characteristics and assumptions of rationality fail to accommodate the flexibility and contradictions that characterize much drug use. Although direct information to individuals and advice about safe drug-use practices must always be a key component of harm reduction programs, this must be complemented with attention to the settings and contexts that spawn risk. This means focusing on the risk environment that creates vulnerability to risky drug-use practices. 6 notes and 82 references