Reductions in convictions for violent crime during opioid maintenance treatment: a longitudinal national cohort study

Abstract

Background: Although opioid maintenance treatment (OMT) has been found to reduce crime, less is known about its associations with violent crime. This study investigates changes in violent crime convictions prior to, during, and after OMT, and examines the relationship between violent crime convictions prior to OMT with the risk of violent and non-violent crime convictions during treatment.

Methods: The cohort comprised all who started OMT (n=3221) in Norway between 1997 and 2003. Treatment data were cross linked with the national Crime Registry. Convictions for violent crime 3 years prior to, during, and after treatment were studied.

Results: Violent crime rates were significantly reduced during OMT compared with before treatment, for both men and women. The rate of convictions for violent crime during OMT was halved amongst those who remained in treatment. The reduction was less pronounced for those who left treatment: for this group, the rate of violent convictions after OMT was higher than before treatment. The risk of convictions for violent and non-violent crime during OMT was highest for those with violent convictions prior to treatment.

Conclusions: Violent crime is reduced during OMT. Screening for violent behaviour and violence risk assessment should be implemented in the treatment system.