• Cocaine;
  • heroin;
  • HIV;
  • injecting drug use;
  • non-injecting drug use;
  • respondent-driven sampling


Aims  To characterize heroin and cocaine users in New York City who have changed from injection to non-injection drug administration and to identify factors associated with long-term non-injection use.

Design  Two cross-sectional studies of heroin and cocaine users in New York City.

Settings and participants  New admissions were recruited at drug abuse treatment programs (2000–04) and respondent-driven sampling was used to recruit drug users from the community (2004). Both injecting and non-injecting drug users participated in each study. ‘Former injectors’ were defined operationally as people who had used heroin and/or cocaine in the 6 months prior to the interview and who had injected illicit drugs in the past, but whose most recent injection was more than 6 months before the study interview. ‘Current’ injectors were defined as people who had injected heroin and/or cocaine in the 6 months prior to the interview.

Measurements  A structured interview on drug use history was administered, and a serum sample was collected and tested for the human immunodeficiency virus (HIV).

Findings  A total of 104 former injectors was recruited for the drug abuse treatment program study, and 229 current injectors were recruited for the community recruitment study; 160 former injectors and 1731 current injectors were recruited from the drug abuse treatment study. Compared with the current injectors, former injectors were older and more likely to be African American. The former injectors reported long intervals since their most recent injection, a mean of 8 years in the drug abuse treatment program study and a mean of 12 years in the community recruitment study. The most common reasons for stopping injection drug use included concerns about health, social stigmatization and self-image, and preference for intranasal use as a route of drug administration. The results were highly consistent across the two studies.

Conclusions  The transition from injection to non-injection use appears to be relatively stable behavior change for many former injectors, who report a decade or more without injecting. Developing a greater understanding of the transition from injection to stable non-injection drug use may provide insights into the natural histories of drug use and addiction.