Forced migrants (i.e., asylum seekers and refugees) experience greater mental health disparities and inequities in care. Mental health services and systems lack clear policy on integrated mental healthcare. Understanding the causal mechanisms of integrated mental health for migrants can promote a resilient and adaptive health and social care system. However, to achieve a functional mental health service integration, there is a need to understand how and why mental health system integration works and under what health systems conditions. The purpose of this realist review protocol will be to outline a process for refining an initial programme theory (IPT), developed through deliberative dialogues with key interest groups in British Columbia, Canada, and to test the IPT against the global evidence base.

A realist review is an interpretive methodological approach to synthesising the literature based on the realist philosophy of science. Realist reviews are pragmatic approaches to theory development because they involve the participation of real-world actors or people who work within complex systems. Realist reviews are particularly useful for synthesising complex knowledge. We plan to conduct a seven-step review process, with iteration between each step. Steps 1–3 have already been completed in our previous work and included the development of an IPT, which will be refined systematically by exploring the global literature and consulting with an international advisory group. These will be used iteratively to identify, test and refine the programme theory. The quality of included literature will be appraised using the relevance, richness and rigour criteria and the realist quality appraisal tool, TAPUPASM (transparency, accessibility, propriety, utility, purposiveness, accuracy, specificity and modified objectivity). Steps 4–7 will include data extraction and realist analysis through retroductive theorising using the ICAMO (intervention, context, actor, mechanism and outcome) heuristic to help distinguish actors and resources from contexts, mechanisms and outcomes.

Ethics approval for the deliberative dialogue interviews that inform this realist review and IPT were obtained by the University of British Columbia (ref: REB Number: H22-03195). Study recruitment occurred between 21 November 2023 and 16 January 2024. All participants provided informed consent to take part in deliberative dialogues and to have their interviews audio recorded and transcribed for the purpose of this research. We will disseminate results of the review through academic papers, conference presentations and through iterative interest group workshops and discussions.

CRD42024580083.