Trajectories of heroin use: 10-11-year findings from the Australian Treatment Outcome Study.
The authors followed up 428 of the original 615 participants of the Australian Treatment Outcome Study originally recruited as part of an NHMRC funded NDARC study in 2001 and 2002.
The majority of the original cohort (87.0%) was recruited upon entry to treatment (maintenance therapies, detoxification and residential rehabilitation), and the remainder from non-treatment settings (e.g. needle and syringe programmes). Two thirds of the original cohort were male with a mean age of 29 years.
The eleven year follow up, also funded by an NHMRC grant, focused upon 428 participants for whom data on heroin use were available over 10–11 years following study entry.
Six trajectory groups were identified. One in five (22.1%) were classified as having ‘no decrease‘ in heroin use, with the probability of using remaining high during the 10–11 years. One in six (16.1%) were classified as demonstrating a ‘rapid decrease to maintained abstinence’. The probability of heroin use among this group declined steeply in the first 2–3 years and continued to be low.
The remaining trajectories represented other fluctuating patterns of use. Few baseline variables were found to predict trajectory group membership.
The present study provides clinically relevant information on contemporary trajectories of heroin use and has identified a number of areas for further research. It also confirms the essential role of long-term follow-up in examining the natural course of heroin dependence.
It is clear that long-term trajectories of the disorder are diverse. For some, heroin dependence is a chronic, debilitating disorder requiring early intervention and a long-term response. There were, however, few characteristics found to predict which path a person might take. In particular, there was little to differentiate those who would continue to use and those who would achieve maintained abstinence. The path one takes, however, has important implications for long-term outcomes. Further research is needed to improve our understanding of factors that underlie group membership and the role of dynamic factors that may influence trajectories.