Interventions to reduce harms related to drug use among people who experience incarceration: A systematic review

Abstract 
Background:
Mortality, suicide, self-harm, co-morbid substance use and mental illness are elevated among people who are incarcerated. There is a wide range of interventions aimed at reducing these harms in this population; however, there has been no systematic review of the impact of these interventions. The aim of this review is to examine the impact of interventions delivered to people who use drugs (PWUD) during incarceration or post-release from incarceration, on a wide range of outcomes. 

Methods: 
Embase, MEDLINE and PsycINFO databases were searched through August 2022 for studies published from 1980 onwards. All studies evaluating the effectiveness of any intervention on drug use, recidivism outcomes, sexual or injecting risk behaviours, or mortality among people who use psychoactive drugs and who were currently or recently incarcerated were included. Studies without a comparator were excluded. Data extracted from each study included demographic details, interventions, and comparisons. Pooled odds ratios/risk ratios were calculated using random-effects meta-analyses. 

Results:
119 Studies were included. Receiving OAT in prison reduced the risk of death in prison (1 study; HR 0.25; 0.13-0.48). Receiving OAT in the first four weeks following release reduced risk of death in the community (2 studies; RR 0.24; 95% CI 0.15-0.37). Therapeutic community interventions reduced rearrest at 6 – 12 months (6 studies; OR 0.72; 95% CI 0.55-0.95) and reincarceration at 24 months (2 studies; OR 0.66; 95% CI 0.48-0.96). There was limited evidence that OAT and needle syringe provision are effective in reducing injecting risk behaviours and needle/syringe sharing. There were no evidence of a benefit of OAT, psychosocial interventions, or case management on recidivism or drug use post-release. 

Conclusions:
There are effective interventions to reduce mortality and recidivism for PWUD who have been incarcerated. There are also significant research gaps examining the impact of interventions during incarceration for PWUD.