Authors' objectives: People with severe mental illness who experience co-occurring substance use experience poor outcome including suicide, violence, relapses and use of crisis services. They struggle to access care and treatment due to a lack of an integrated and co-ordinated approach which means that some people can fall between services. Despite these concerns, there is limited evidence as to what works for this population. To undertake a realist evaluation of service models in order to identify and refine programme theories of what works under what contexts for this population. Approximately 30–50% of people with serious mental health illness (SMI) have a coexisting alcohol/drug condition, leading to significant negative health and social outcomes. Despite the scale of these co-occurring conditions, there is limited evidence to inform treatment, with the evidence that is available failing to provide a definitive answer as to how services and treatments should be best delivered to improve health and other outcomes for this diverse group. The aim of this project was to use a realist approach to understand what works, how, for whom and in what circumstances by synthesising data from published and grey literature, mapping and describing the characteristics of UK services and service provision, and undertaking in-depth focus groups and interviews in locations picked to be representative of the range of provision identified in the mapping and review of the literature. The outcome was a set of refined programme theories (PTs), which underpin an explanatory framework that can be used to inform future research, policy and practice.

Authors' results and conclusions: Eleven initial programme theories were generated by the evidence synthesis and in conjunction with stakeholders. These theories were refined through focus groups and interviews with 58 staff, 25 service users and 12 carers across the 6 case study areas. We identified three forms of service provision (network, consultancy and lead and link worker); however, all offered broadly similar interventions. Evidence was identified to support most of the 11 programme theories. Theories clustered around effective leadership, workforce development and collaborative integrated care pathways. Outcomes that are meaningful for service users and staff were identified, including the importance of engagement. The realist evaluation co-occurring study provides details on how and in what circumstances integrated care can work better for people with co-occurring severe mental health and alcohol/drug conditions. This requires joined-up policy at government level and local integration of services. We have also identified the value of expert clinicians who can support the workforce in sustaining this programme of work. People with co-occurring severe mental health and alcohol/drug conditions have complex and multifaceted needs which require a comprehensive and long-term integrated approach. The shift to integrated health and social care is promising but will require local support (local expert leaders, network opportunities and clarity of roles). Work package 1: realist synthesis A set of 11 refined PTs were identified from the literature and these broadly fell into three interconnecting categories: committed leadership; clear expectations regarding COSMHAD from mental health and substance use workforces; and clear processes to co-ordinate care. Co-occurring serious mental illness and substance use is a common phenomenon in mental health care, yet the mental health, substance use and related services remain ill-equipped to meet the needs of people with COSMHAD. The RECO study provides details on how and in what circumstances integrated care can work better for people with COSMHAD. This requires joined-up policy at government level and local integration of services. We have also identified the value of expert clinicians who can support the workforce in sustaining this programme of work. People with COSMHAD have complex and multifaceted needs which require a comprehensive and long-term integrated approach. The shift to integrated health and social care is promising but will require local support (local expert leaders, network opportunities and clarity of roles). Future research should focus on evaluating whole system approaches as opposed to reductionist individual interventions. This includes establishing the cost-effectiveness of key components of the COSMHAD models.

Authors' methods: Realist synthesis and evaluation using published literature and case study data. Mental health, substance use and related services that had some form of service provision in six locations in the United Kingdom (five in England and one in Northern Ireland). People with lived experience of severe mental illness and co-occurring substance use, carers and staff who work in the specialist roles as well as staff in mental health and substance use services. The requirement for online data collection (due to the COVID-19 pandemic) worked well for staff data but worked less well for service users and carers. Consequently, this may have reduced the involvement of those without access to information technology equipment. We conducted a series of distinct, yet interrelated work packages (WPs) to achieve our research objectives. The study was impacted by COVID-19. The national response to COVID-19 in health and social care impacted on responses to requests for information in the UK mapping exercise. Therefore, there may have been additional services in existence that we did not identify. Due to social distancing and various national and regional lockdowns, the data collection was almost entirely conducted online. While we collected our target sample of staff, we did not recruit to target for the service user and carer focus groups and interviews. Online methods were a barrier to some people. However, the data from the service user and carers were obtained across most of the sites and were sufficient to answer the research questions.

Project Status: Completed

URL for project: https://www.journalslibrary.nihr.ac.uk/programmes/hta/NIHR128128

Year Published: 2024

URL for published report: https://www.journalslibrary.nihr.ac.uk/hta/JTNT0476

URL for additional information: English

English language abstract: An English language summary is available

Publication Type: Full HTA

Country: England, United Kingdom

DOI: 10.3310/JTNT0476

Organisation Name: NIHR Health Technology Assessment programme

Contact Address: NIHR Journals Library, National Institute for Health and Care Research, Evaluation, Trials and Studies Coordinating Centre, Alpha House, University of Southampton Science Park, Southampton SO16 7NS, UK

Contact Name: journals.library@nihr.ac.uk

Contact Email: journals.library@nihr.ac.uk