Noah Harwood, Seilin Uhm, David Wright, Katherine Hunt
Seven studies met the criteria (six qualitative, one mixed-methods; n = 239 participants were involved in six papers; one paper stated they interviewed 11 jails rather than participants). Study samples were drawn from the UK and the USA except May et al. (2020), which was conducted in Wales. In all, 12 recurring determinants were clustered within three domains: institutional (e.g. dispensing procedures and staffing levels), social (e.g. peer hierarchies and informal economies) and individual (e.g. pain management needs and substance-use history). Some determinants acted as both barriers and facilitators depending on local configuration. The interplay of environment, behaviour and personal agency suggests that single-level interventions are unlikely to curb diversion sustainably.
PURPOSE: The purpose of this study is to synthesise empirical evidence on the factors that enable or hinder diversion of prescribed medicines in prison populations.
DESIGN/METHODOLOGY/APPROACH: A systematic review of primary studies published in English between January 2018 and 31 July 2025 was undertaken in MEDLINE, CINAHL and PubMed. Methodological quality was appraised with the Long-French & Brooks adaptation of CASP. Findings were integrated through narrative synthesis and mapped against Smith's Model of Addiction.
FINDINGS: Seven studies met the criteria (six qualitative, one mixed-methods; n = 239 participants were involved in six papers; one paper stated they interviewed 11 jails rather than participants). Study samples were drawn from the UK and the USA except May et al. (2020), which was conducted in Wales. In all, 12 recurring determinants were clustered within three domains: institutional (e.g. dispensing procedures and staffing levels), social (e.g. peer hierarchies and informal economies) and individual (e.g. pain management needs and substance-use history). Some determinants acted as both barriers and facilitators depending on local configuration. The interplay of environment, behaviour and personal agency suggests that single-level interventions are unlikely to curb diversion sustainably.
RESEARCH LIMITATIONS/IMPLICATIONS: Evidence is predominantly from US jail/prison contexts with limited demographic diversity; more UK/EU prison research is needed.
PRACTICAL IMPLICATIONS: This study co-designed dispensing protocols, person-centred communication training and expanded access to MOUD (including diversion-resistant formulations) warrant testing.
SOCIAL IMPLICATIONS: Medication diversion in prisons has wider social consequences beyond clinical risk. It can fuel informal trading economies, debt, intimidation and violence and can undermine trust between people in prison and health-care staff. Fear of diversion may lead to restrictive dispensing practices that reduce timely access to legitimate therapies, potentially widening health inequalities and increasing relapse and self-harm risk. Addressing diversion, therefore, supports safer prison communities, improves equitable access to care and strengthens continuity of treatment on release.
ORIGINALITY/VALUE: This study co-designed dispensing protocols, person-centred communication training and expanded access to Medication for Opioid Use Disorder (MOUD) (including diversion-resistant formulations) warrant development and testing.