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.