The effectiveness of diversion programmes for offenders using Class A drugs: a systematic review and meta-analysis

Aims: To review existing evidence on effectiveness of community-based diversion programmes for Class A drug-using offenders.

Methods: 31 databases were searched for studies published 1985-2012 (update search 2012-2016) involving community-based Criminal Justice System diversion of Class A drug users via voluntary or court-mandated treatment.

Findings: 16 studies were initially included (US, 10; UK, 4; Canada, 1; Australia, 1). There was evidence for a small impact of diversion to treatment on drug use reduction (primary Class A drug use: OR 1.68, CI 1.12-2.53; other drug use: OR 2.60, 1.70-3.98). Class A drug users were less likely to complete treatment (OR 0.90, 0.87-0.94) than users of other drugs. There was uncertainty surrounding results for offending, which were not pooled due to lack of outcome measure comparability and heterogeneity. Individual studies pointed to a minor effect of diversion on offending. Findings remained unchanged following an update review (evidence up to March 2016: US, 3; Australia, 1).

Conclusions: Treatment accessed via community-based diversion is effective at reducing drug use in Class A drug-using offenders. Evidence of a reduction in offending amongst this group as a result of diversion is uncertain. Poor methodological quality and data largely limited to US methamphetamine users limits available evidence.