Long-term Outcome of Chronic Drug Use: The Amsterdam Cohort Study among Drug Users

In the present study, mortality rates and prevalence of abstinence from illicit drugs among persons with a history of addiction to heroin, cocaine, and/or amphetamines were estimated along the drug-using career time scale. Follow-up data on drug use and vital status were analyzed for participants in the Amsterdam Cohort Study among Drug Users (n = 899; 1985-2002). Participants in the study were primarily recruited at low-threshold methadone outposts. It was estimated that at least 27% of drug users had died within 20 years after starting regular drug use; for half, death had been due to causes unrelated to human immunodeficiency virus. A favorable trend towards abstinence with increasing time since initiation of regular use was observed. However, among those alive, the estimated prevalence of abstinence for at least 4 months from the above drugs and methadone was only 27% at 20 years since initiation. A higher age at initiation, a calendar year of initiation before 1980, and a Western European ethnic origin were associated with higher prevalence of abstinence. These results indicate that the concept of "maturing out" to a drug-free state does not apply to the majority of drug users. Further studies on determinants of individual transitions in drug use are important in order to establish evidence-based intervention strategies.