Understanding the impact of opioid agonist treatment in reducing crime

August 2019
In a recently published study, we examined the link between opioid agonist treatment (OAT) and crime in nearly 11,000 people in New South Wales (NSW).

About the study

The observational retrospective study published online in Lancet Public Health, investigated the effectiveness of OAT, specifically methadone and buprenorphine, on crime rates. The unique study design linked data on treatment episodes, criminal charges and mortality for 10,744 people entering OAT for the first time in NSW between 2004 and 2010. 

The study comprehensively examined the potential effect of OAT on charge rates, considering various time periods within an OAT episode and varying patterns of engagement in OAT across treatment episodes and episode lengths. Most people in the cohort were male (71 per cent) and non-Indigenous (77 per cent), with a median age of 29. In the four years before treatment entry, 60 per cent had previously been charged with a criminal offence and 36 per cent had been in prison. 

Staying in treatment continuously, rather than cycling in and out of treatment, was associated with reduced criminal offending. Being younger, Indigenous, and having more criminal charges before treatment entry were associated with an increased risk of criminal offending after starting treatment.

Key findings

Our findings show that OAT is associated with a significant reduction in overall charge rates and is most protective with increased treatment engagement. Importantly, we found that episodes of continuous treatment were associated with lower charge rates compared to those where individuals cycled in and out of treatment. We therefore need to focus on encouraging greater retention in treatment to maximise the long-term health and social benefits of OAT.

Although pharmacological treatment provides many health benefits and reduces criminal offending, other factors that may contribute to offending such as poverty, unemployment and social and environmental circumstances also need to be addressed. There is a complex relationship between opioid dependence, OAT and crime, and it’s important that we look at the broader context in which offending occurs. Hence, the reasons motivating an individual to offend also need to be considered to address the full scope of the issue. It is almost important to bear in mind that not all individuals who are opioid dependent commit crimes - in our study 46% of people had no criminal convictions.

Overall, from this study we know that OAT reduces offending, and that longer periods of treatment appear to be most beneficial in achieving improved crime rates. This adds to other research showing that most benefits of OAT come with being in treatment for longer periods, even many years.


It is well known that OAT has many health benefits including reducing heroin and injecting drug use, and protecting against overdose death. Contact with the criminal justice system – both in terms of crime and imprisonment – among opioid dependent people is associated with a significant economic burden to society and has many negative impacts for individuals, both in the short and long-term. For example, periods of incarceration can negatively affect an individual’s health and social functioning, as well as have future negative consequences, such as limiting capacity to gain employment.

There is therefore a need to examine the effectiveness of interventions that might reduce these events and improve outcomes for individuals who are opioid dependent. As such, there is ongoing interest in understanding the benefits and value of OAT programs to inform decisions around how this program can be implemented to achieve the best possible outcomes for individuals.

Next steps

Given the complexity of the issue, further work is needed to understand where the differences lie in terms of individual benefits from OAT on patterns of offending in order to better support those individuals who continue to offend while in treatment. Another area of interest is understanding the trajectories of drug use, crime and treatment among younger people in order to provide timely and appropriate intervention before problems escalate.

For access to the Article and Comment please see: https://www.thelancet.com/journals/lanpub/article/PIIS2468-2667(19)30060-X/fulltext 

NDARC is supported by funding from the Australian Government Department of Health under the Drug and Alcohol Program.


Gisev N, Bharat C, Larney S, Dobbins T, Weatherburn D, Hickman M, Farrell M, Degenhardt L. The effect of entry and retention in opioid agonist treatment on contact with the criminal justice system among opioid-dependent people: a retrospective cohort study. Lancet Public Health. 2019; 4(7):e334-e342. DOI: 10.1016/S2468-2667(19)30060-X.