Long-term patterns of treatment use for opioid use disorder (OUD): Findings from the 18-20-year Australian Treatment Outcome Study

Jack Wilson, Katherine L. Mills, Matthew Sunderland, Tom P. Freeman, Madeleine Keaveny, Katherine Haasnoot, Maree Teesson, Paul S. Haber, Christina Marel

Research output: Contribution to journalArticlepeer-review


Background: Opioid-related deaths continue to increase to unprecedented rates in many regions of the world. While long-term stable treatment has been shown to reduce associated morbidity and mortality, discontinuation and numerous treatment episodes are common, limiting our understanding of the common course of treatment and associated characteristics. Therefore, using an 18-20-year follow-up of people with heroin dependence, we aimed to identify i) distinct trajectories of treatment use, ii) whether baseline characteristics predict treatment trajectory group membership, and ii) if group membership is associated with characteristics at 18-20-years post-baseline. Methods: A total of 615 people with heroin dependence were recruited from maintenance therapy, detoxification, residential rehabilitation, or needle and syringe programs as part of the Australian Treatment Outcome Study (ATOS), a longitudinal cohort followed up on seven occasions over 18-20-years between 2001 and 2021. Of those who had complete data (n = 393), group-based trajectory modelling and a series of multinomial logistical regressions were conducted. Results: Five trajectories of treatment use were identified: i) ‘long-term low treatment’ (17.2%), ii) ‘rapid increase with gradual decrease’ (13.9%), iii) ‘late increase’ (17.8%), (iv) ‘long-term treatment’ (27.7%), and (v) ‘reduced treatment’ (23.5%). Entering maintenance treatment at baseline predicted trajectory group membership, while trajectory group membership was associated with demographics and the use of heroin, methamphetamine, alcohol, and benzodiazepines at 18-20-years. Conclusions: In one of the longest cohort studies of its kind, we characterised distinct trajectories of treatment use in people with heroin dependence over 18-20-years. Clinicians should be aware of the potential impact of demographics and substance use on long-term treatment use. Despite the well-documented benefits of long-term treatment, some patients may be able to achieve abstinence from opioids without engaging in treatment over the life-course.

Original languageEnglish
Article number104187
JournalInternational Journal of Drug Policy
Early online date13 Sept 2023
Publication statusPublished - 31 Oct 2023

Bibliographical note

Funding Information:
This work was funded by the Australian National Health and Medical Research Council (NHMRC) Project Grant number APP1147212 , and supported by an NHMRC PhD scholarship awarded to Jack Wilson, and NHMRC Fellowships to Christina Marel, Katherine L Mills and Maree Teesson. The project was also supported by Matilda Centre funding.


  • group-based trajectory modelling
  • longitudinal cohort study
  • opioid use disorder
  • treatment

ASJC Scopus subject areas

  • Medicine (miscellaneous)
  • Health Policy


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