The Effectiveness of Germany's Compulsory Forensic Addiction Treatment: A Quasi-Experimental Study of Recidivism Using Matched Groups.

Substance use disorders are highly prevalent among offenders and are closely associated with increased rates of recidivism. This service evaluation assessed the effectiveness of compulsory forensic treatment for offenders with substance abuse in reducing recidivism. The study compared recidivism rates of 279 offenders who received mandated treatment under Section 64 of the German Criminal Code with those of a matched control group of 274 incarcerated individuals. An additional propensity score analysis confirmed the adequacy of the case-to-case matching. Over a mean follow-up of 6.5 years, the absolute risk reduction remained stable at around 16.5%, with recidivism rates at 7 years of 63.4% in the treatment group and 80.3% in the prisoner group. These findings attest to the effectiveness of compulsory addiction treatment in reducing recidivism compared to subjects who only serve a prison sentence, even though a substantial number (48%) of patients had been returned to prison but were still included in the treatment group at follow-up (intention-to-treat-analysis). The practical implications of these findings are discussed in light of recent legislative changes affecting the application of Section 64.