• A new study has examined the link between opioid agonist treatment (OAT) and crime in nearly 11,000 people in New South Wales.
  • OAT was associated with a reduction in overall charge rates and was more protective as treatment engagement increased.

Medications for opioid dependence significantly reduce crime rates, a study by researchers from the National Drug and Alcohol Research Centre (NDARC) at UNSW Sydney, has found. 

The observational retrospective study published online in Lancet Public Health, investigated the effectiveness of opioid agonist treatment (OAT), specifically methadone and buprenorphine, on crime rates in New South Wales (NSW), Australia. 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.

Lead author, Dr Natasa Gisev, a UNSW Scientia Fellow at NDARC, said the study added important new evidence to support the benefits of OAT in reducing crime rates. 

“Our findings show that OAT is associated with a significant reduction in overall charge rates and is most protective with increased treatment engagement,” said Dr Gisev.

“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.” 
Dr Gisev highlighted that reducing offending is a complex issue and many individuals will require additional support.

“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,” said Dr Gisev. 

In an accompanying commentary, Professors Tim Millar and Roger Webb from the University of Manchester, UK, said the study provided further robust evidence for the effectiveness of OAT.

“The study makes a valuable contribution to the literature in showing that, in general terms, OAT is associated with reduced offending risk, but that this relationship is also complex,” they write.

Notes to editors: Earlier studies in Australia and Canada have shown lower offending rates during periods in which individuals were receiving methadone treatment. In the UK, crime reductions have only been shown with continuous treatment with methadone, with non-continuous treatment having little benefit. The effect of buprenorphine treatment has been less widely examined. 

OAT is currently available in Australia in the form of methadone and buprenorphine (+/- naloxone), generally with supervised daily dosing. This is the first study to comprehensively examine the effect of various exposures to OAT in a whole population. Its limitation is that as an observational study, the results cannot infer a causal relationship between treatment exposure and reductions in criminal offending.

Citation: 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. 

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.