O'Leary, Chris and Ralphs, Rob and Stevenson, Jennifer and Smith, Andrew and Harrison, Jordan and Kiss, Zsolt and Armitage, Harry (2024) The effectiveness of abstinence-based and harm reduction-based interventions in reducing problematic substance use in adults who are experiencing homelessness in high income countries: a systematic review and meta-analysis. Campbell Systematic Reviews , 20 , (2) .