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

Abstract

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.

Keywords:

• Crime
• diversion
• offenders
• substance abuse
• systematic review
• treatment

Acknowledgements

We would like to express our thanks to the following people who provided essential support to the project: Vanessa Haves, Naomi Humber, Heather Noga, and Louise Robinson from the Offender Health Research Network, Michael Donmall and Donal Cairns from the National Drug Evidence Centre at The University of Manchester and Michael Farrell from the National Drug and Alcohol Research Centre at UNSW, Australia. Seena Fazel, Department of Psychiatry, University of Oxford receives funding from Wellcome. Matthew Hickman acknowledges support from NIHR Health Protection Research Unit in Evaluation. We are grateful to anonymous reviewers for their useful comments on an earlier draft of this manuscript.

Disclosure statement

Karen P. Hayhurst has received grant research funding from Change, Grow, Live (CGL), a third-sector provider of substance misuse services. Tim Millar and Andrew Jones have received grant research funding from CGL, the Home Office, Public Health England and the Department of Health. Maria Leitner, Linda Davies, Rachel Flentje, Matthew Hickman, Seena Fazel, Soraya Mayet, Carlene King, Jane Senior , Charlotte Lennox, Rochelle Gold, Deborah Buck and Jennifer Shaw declare no competing interests.

Funding

Work on the effectiveness and cost-effectiveness of diversion programmes was supported by the UK National Institute for Health Research (NIHR) (under grant number 09/109/04) and reported in the Health Technology Assessment (HTA) Monograph series.

The funder of the study had no involvement in study design, data collection, manuscript preparation or the decision to submit this paper for publication.