Transitions in drug use in a new generation of problem drug users in Amsterdam: a 6-year follow-up study.

Aims: This study describes the transitions in drug use in Amsterdam among young drug users (YDUs) who are inhaling or injecting cocaine or using illicitly obtained opiates.

Methods: From 2000 until 2003, 187 YDUs (< or = 30 years) were recruited of whom 126 were followed into 2007.

Results: During the 6 months prior to inclusion, 95% used cocaine, 60% used illicit opiates, and 9% injected more than once a week. During follow-up, the incidence of new-onset heroin use was 4.8/100 person-years. The incidence of injecting was much lower for never-injectors (2.1/100 person-years) than for ever-injectors who relapsed (13.2/100 person-years). Transition to abstinence or nonfrequent drug use is common (23/100 person-years), mostly followed by a relapse (73/100 person-years). Polydrug users were less likely to discontinue their frequent drug use than monodrug users.

Conclusions: Treatment services should target the crack cocaine users to prevent further marginalization and, during abstinence, to prevent relapse. Although the prevalence and incidence of injecting are relatively low, it is still an option for opiate users, especially those with a history of injecting.