Data from the national OMT register and the crime statistics were cross- linked.
Opioid maintenance treatment was found to be associated with significant reductions in criminal convictions in this national cohort. During treatment the overall rates of criminal convictions were reduced to less than half of pre-treatment levels. Patients in continuous treatment had the fewest convictions during treatment. The highest rates were found among patients out of treatment after several treatment episodes. All groups had significantly fewer criminal convictions during treatment compared to before treatment. Those who left treatment, permanently or temporarily, relapsed into high levels of convictions outside treatment. Staying in OMT for 2 years or more was associated with significantly reduced rates of convictions during treatment. Younger age and pre-treatment criminal convictions were associated with significantly more convictions during treatment. Hence, it is important to both identify and to have a particular focus on patients in risk of dropping out of treatment in order to retain patients in OMT.