Participation in opioid substitution treatment reduces the rate of criminal convictions: evidence from a community study.

Objective: Positive outcomes associated with opioid substitution treatment include reduced illicit opioid use and lower risk of HIV and other blood-borne infections. The effect on the reduction of criminal activity remains unclear. Our aim was to investigate the impact of treatment on criminal activity using conviction register data.

Method: This observational retrospective study included all new patients (N=169) enrolled in an opioid substitution treatment program in the Helsinki University Central Hospital Clinic for Addiction Psychiatry between 2000 and 2005. Psychiatric and psychosocial services were provided as part of the program. Patient treatments were followed up for 18 months. Data on criminal convictions were collected for approximately 3 years before and after the start of treatment.

Results: Mean rates of convictions decreased significantly during treatment. The effects were similar for total convictions, drug convictions, and property crime convictions. Although the numbers of violence and drunk driving convictions were too small to be analysed separately, on a bivariate level there was no indication of reduction in these crime types. Patients with amphetamine co-dependence fared best. Sex, age, other co-dependences or psychiatric diagnoses, negative urine analyses during the treatment, and dropping out from treatment had little impact on the outcomes.

Conclusions: Opioid substitution treatment seems to reduce criminal activity effectively. However, more information is needed to determine how treatment influences different types of criminality and which types of patients benefit most.