Not a life sentence: Heroin study challenges assumptions about long-term outcomes

Recent findings from the Australian Treatment Outcome Study (ATOS), Australia’s longest naturalistic study of heroin dependence, indicate that heroin dependence is not necessarily a life sentence, with three in four participants not using heroin at 11-years following study entry. Moreover, a considerable proportion maintained long-term abstinence without the need for ongoing treatment. Researchers from the University of Sydney’s Matilda Centre for Research in Mental Health and Substance Use (the Matilda Centre) and the National Drug and Alcohol Research Centre (NDARC) at UNSW Sydney, say further research is needed to understand what factors made these participants so successful.

Increases in heroin use are contributing to dramatic rises in opioid dependence and opioid-related deaths worldwide, and heroin remains a significant public health issue in Australia. While research has consistently shown that long-term stable treatment is key to achieving positive outcomes, relatively little is known about treatment pathways over the long-term, and which factors are vital for long-term improvement.  

To better understand these relationships over the long-term, the 11-year follow up of ATOS involved re-establishing contact with a cohort of 615 Australians with heroin dependence and reinterviewing them about their substance use and treatment utilisation. The cohort was initially recruited into the study in 2001-02, and were interviewed on six occasions. Findings showed five distinct groups of heroin use and treatment utilisation:

• A group who reduced heroin use over time while in long-term treatment (17%);
• A group who achieved long-term abstinence alongside a reduction in treatment utilisation (13%);
• A group who demonstrated no decrease in heroin use alongside high rates of treatment utilisation (12%);
• A group who gradually reduced their heroin use alongside a late increase in treatment utilisation (9%); and
• A group who experienced relapses in heroin use alongside fluctuations (increases or decreases) in treatment utilisation (9%).

Although treatment responses varied, the finding that 1 in 8 participants demonstrated decreasing heroin use alongside reductions in treatment utilisation, until there was long-term abstinence without the need for ongoing treatment, challenges previous assumptions that long-term abstinence is not possible without ongoing treatment.

“This is exciting, because it shows that heroin dependence is not necessarily the long-term, chronic relapsing condition that we have always considered it to be,” explains Dr Christina Marel from the Matilda Centre, who coordinates the ATOS project. “Many people experiencing heroin dependence can feel as though it’s a ‘life sentence’, which is not only unhelpful and highly stigmatising, but also inaccurate.”

“There are many factors that can influence which pathway a person can take in terms of their heroin use, and we are just beginning to understand how complex the long-term relationships between some of these factors are in a person’s life,” says the Matilda Centre’s Associate Professor Katherine Mills. “There were few factors that were able to distinguish between those who would do really well, and those who might not have such long-term positive outcomes. Further research is needed to untangle these relationships, but this is a great start.”

With further funding from the NHMRC, the ATOS team has recently started the 18-20-year follow-up of the ATOS cohort which will provide vital information on the longer term impact of heroin use and treatment on physical and mental health. The study is being coordinated by Dr Christina Marel and her fellow investigators, including the study’s Chief Investigator, Professor Maree Teesson. Other investigators at the Matilda Centre include Associate Professor Katherine Mills, Associate Professor Tim Slade, as well as NDARC’s Professor Shane Darke and Dr Joanne Ross.  

Interested in learning more about ATOS? Read the latest research findings in Lancet eClinicalMedicine or contact the Matilda Centre at matilda.centre@sydney.edu.au

1. Marel C, Mills KL, Slade T, Darke S, Ross J, Teesson M. Modelling Long-Term Joint Trajectories of Heroin Use and Treatment Utilisation: Findings from the Australian Treatment Outcome Study. EClinicalMedicine [Internet]. 2019 Aug [cited 2019 Sep 13]. Available from: https://doi.org/10.1016/j.eclinm.2019.07.013
2. National Institute on Drug Abuse (NIDA). Overdose death rates National Institute of Health. Updated September 2017. Available from: Martins SS, Sarvet A, Santaella-Tenorio J, Saha T, Grant BF, Hasin DS. Changes in US lifetime heroin use and heroin use disorder: prevalence from the 2001–2002 to 2012–2013 National Epidemiologic Survey on alcohol and related conditions. JAMA Psychiat 2017;74:445–55.
3. Addiction EMCfDaD. European drug report 2017: Trends and developments. Luxembourg: Publications Office of the European Union; 2017.
4. Australian Bureau of Statistics (ABS). Drug Induced Deaths in Australia. Updated September 2018. Available from:https://www.abs.gov.au/ausstats/abs@.nsf/Lookup/by%20Subject/
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