A systematic review and meta-analysis on the effects of European drug treatment programmes on reoffending

This article presents the results of a systematic review and meta-analysis on the effects of treatment programmes for drug abusing offenders in Europe, using stringent eligibility criteria to control for threats to internal validity. A literature search of approximately 37,000 titles revealed 15 sound evaluations from six countries, containing 3953 participants. There were significant positive overall effects of treatment on crime (d=0.47) and...