The 6-STEP AMICABLE Programme: Addressing Mental health In Custody A Brief Learning Environment: A peer-led 6-step problem-solving intervention using an interrupted time series and integrated matched cohort study design.

Background The mental health problems of people incarcerated in prison is a worldwide public health concern. Prisoners are more likely to experience common mental health disorders, and once diagnosed, are more likely to reoffend. Recent evidence promotes use of brief evidence-based interventions that consider the whole prison environment. Problem-Solving Therapy is one such example. Aim Using a brief peer-led Problem Support Mentor Scheme (PSMS), we aim to improve the mental health and well-being of prisoners. Method and design WP1: Working with staff stakeholders and prisoners we will develop an implementation tool kit to enhance engagement with the scheme. In a series of staff stakeholder discussions, co-produced prisoner workshops the WP will generate a tool kit to support the implementation of the scheme; produce a resource protocol and interrogate our existing theory of change model. WP2: We will deliver our implementation model to 40 Mentors per site and undertake a longitudinal process evaluation for 20 Mentors and 20 peers (at 1,3 and 9 months) and up to 32 staff (at 6 and 12 months) post intervention. Interviews with observations of staff and prisoners will inform our understanding of how the intervention is implemented and will feed into a follow-up in WP5. WP3: We will examine whether the PSMS improves mental health. We will conduct an ITS analysis using monthly data on the number of self-harm and violent incidents (28 months before intervention, 12 months during and 15 months post) and conduct a cross-sectional evaluation of depression, quality of life and NHS resource use at pre intervention, 4 and 9 months post to inform WP4. A target sample size of 64 Mentors and 400 peers would detect a medium effect size of 0.3. WP4: We will investigate how much the scheme is likely to cost to deliver and work out whether it is cost-effective using a cost-consequence and cost effectiveness evaluation and data collected in WP3. Short and longer term outcomes will use the EQ-5D-5L to generate Quality-adjusted life-years. WP5: A matched cohort study and qualitative interviews (with up to 25 Mentors and 25 peers) will follow-up released prisoners into the community. The WP will measure the impact on return to custody, use of problem-solving skills in the community and outcomes of housing, employment, mental health and social support networks using a 'through the gate' volunteering opportunity in a sample of around 30 Mentors. Timelines for delivery WP1: Months 1-12 (April 2023-March 2024). WP2: Months 12-27 (April 2024-July 2025). WP3: Months: Routine data obtained from April 2022 to December 2026, analysis months 45-48 (January 2027 to April 2027). WP4: Months 15-40 (July 2024-August 2026). WP5: Months: 12-44 (April 2024-Dec 2026). Anticipated Impact and Dissemination Access to our Problem Support Mentor Scheme is likely to improve the mental health and well-being of prisoners. Our key output will be a clinically and cost effective intervention that improves outcomes of depression, quality of life, self-harm and violent behaviour. A comprehensive dissemination strategy relies heavily on the co-production of information to target different audiences.