Diverting people who use drugs from the criminal justice system: A systematic review of police-based diversion measures (2022)

Background: Previous reviews of the effectiveness of measures to divert those who use drugs from the criminal justice system have focused mainly on post-conviction or post-sentence programs and report mixed results. The present systematic review synthesizes evidence on the effectiveness of police-based diversion measures in reducing criminal offenses and other harms related to drug use and then summarizes evidence from qualitative studies to identify facilitators and barriers associated with the implementation of such measures.
Methods: Eight databases were searched to find evaluations of police-based diversion measures for drug-related offenders. Twenty-seven studies were identified. The vote-count method and the Maryland Scientific Method Scale were used to assess the impact of police-based diversion measures. Themes related to barriers or conditions facilitating the implementation of these measures were extracted from qualitative studies.
Results: Evidence from quantitative studies indicates that in general police-based diversion measures are effective in preventing criminal offending and show promising results for improving participants' health and diminishing social costs as well as costs associated with processing drug-related offenses. There was insufficient evidence to draw conclusions about the effect of police-based diversion measures on drug use, drug accessibility, or changes in participants’ socioeconomic conditions. Findings from qualitative studies suggest that program acceptance by police officers, constructive intersectoral collaboration, clear eligibility criteria, and timely access to services seem to facilitate the implementation and delivery of police-based diversion measures.
Conclusion: Police-based diversion measures can be effective in preventing drug-related criminal offenses and harm. Additional research is needed to evaluate their effect on participants' socioeconomic conditions and drug use as well as drug accessibility.