BackgroundA variety of peer worker roles are being introduced into the mental health workforce in England, in a range of organisational contexts and service delivery settings. The evidence base demonstrating the effectiveness of peer worker-based interventions is inconclusive and largely from outside England. An emerging qualitative literature points to a range of benefits, as well as challenges to introducing the peer worker role.AimsIn this study we aimed to test the international evidence base, and what is known generally about role adoption in public services, in a range of mental health services in England. We also aimed to develop organisational learning supporting the introduction of peer worker roles, identifying learning that was generic across mental health services and that which was specific to organisational contexts or service delivery settings.TeamThe research was undertaken by a team that comprised researchers from a range of academic and clinical disciplines, service user researchers, a peer worker, and managers and service providers in the NHS and voluntary sector. Service user researchers undertook the majority of the data collection and analysis. We adopted a coproduction approach to research, integrating the range of perspectives in the team to shape the research process and interpret our findings.Study designThe study employed a qualitative, comparative case study design. We developed a framework, based on existing evidence and the experiential insight of the team, which conceptualised the challenges and facilitators of introducing peer worker roles into mental health services. The framework was used to inform data collection and to enable comparisons between different organisational contexts, service delivery settings and the perspectives of different stakeholders.SettingsThe study took place in 10 contrasting cases comprising mental health NHS trusts, voluntary sector service providers and partnerships between the NHS and voluntary sector or social care providers. Peer workers were employed in a variety of roles, paid and unpaid, in psychiatric inpatient settings, community mental health services and black and minority ethnic (BME)-specific services.ParticipantsParticipants were 89 people involved in services employing peer workers, recruited purposively in approximately equal proportion from the following stakeholder groups: service users; peer workers; (non-peer) coworkers; line managers; strategic managers; and commissioners.Data collectionAll participants completed an interview that comprised structured and open-ended questions. Structured questions addressed a number of domains identified in the existing evidence as barriers to, or facilitators of, peer worker role adoption. Open-ended questions elicited detailed data about participants’ views and experiences of peer worker roles.Data analysisStructured data were analysed using basic statistics to explore patterns in implementation across cases. Detailed data were analysed using a framework approach to produce a set of analytical categories. Patterns emerging in the structured analysis informed an in-depth interrogation of the detailed data set, using NVivo 9 qualitative software (QSR International Pty Ltd, Victoria, Australia) to compare data between organisational contexts, service delivery settings and stakeholder groups. Preliminary findings were refined through discussion with a range of stakeholders at feedback workshops.FindingsMany of the facilitators of peer worker role adoption identified in the existing evidence base were also evident in mental health services in England, although there were issues around pay, leadership, shared understanding of the role, training and management where good practice was uneven. A number of examples of good practice were evident in the voluntary sector, where peer worker roles had been established for longer and organisations were more flexible. In the NHS there were a range of challenges around introducing peer worker roles into existing structures and cultures of practice. Peer workers were able to engage people with services by building relationships based on shared lived experience – the language they used was particularly important in BME-specific services – but barriers to engagement could be created where roles were overformalised.ConclusionsKey barriers to, and facilitators of, peer worker role adoption were identified, including valuing the differential knowledge and practice that peer workers brought to the role (especially around maintaining personally, rather than professionally defined boundaries); maintaining peer identity in a role of work; changing organisational structures to support peer workers to remain well in their work; and challenging organisational cultures to empower peer workers to use their lived experience. Recommendations for future research include developing a theoretical framework articulating the change mechanisms underpinning ‘what peer workers do’, piloting and formally evaluating the effectiveness and cost-effectiveness of peer worker interventions, and mixed-method research to better understand the impact of working as a peer worker.FundingThe National Institute for Health Research Health Services and Delivery Research programme.