Care pathways are crucial for patients with mental health disorders and should be designed to support integrated rehabilitation while reducing the burden of these disorders. The contemporary shift toward an outpatient follow-up model of care presents an opportunity to improve mental health care beyond the stagnation in advancements in pharmacological treatments. Various pharmacist-led interventions exist and can serve as levers to address ongoing challenges in mental health care pathways: they could help manage difficult transitions, ensure continuity between inpatient and outpatient care, and reduce high rehospitalisation rates. However, the contexts in which these solutions benefit patients and improve care outcomes remain unclear. Thus, the primary objective of this study will be to identify how pharmaceutical solutions contribute to improving mental health care pathways, what works, for whom and in what context. The secondary objective will be to identify the key outcomes currently used to evaluate the impact of pharmaceutical solutions on care pathways.

A systematic realist review will be conducted, following 5 iterative steps to synthesise heterogeneous evidence: (1) Scope definition with a general review of the literature and experts’ discussions, (2) Initial programme theory development based on the preliminary searches, (3) Systematic review for evidence, to refine and test initial programme theory across PubMed, Embase and Web Of Science, (4) Data extraction, including context-mechanism-outcome configurations, and evidence appraisal and (5) Data analysis, synthesis and refined programme theory construction with the realist logic. This process will involve consensus among expert researchers, incorporating insights from individuals with lived experience.

The final programme theory modelling will result in a new framework for pharmaceutical solutions applied in diverse mental health contexts. The findings of this systematic realist review could serve as a guide for implementing pharmaceutical solutions across healthcare settings, ensuring that interventions are evidence-based, contextually relevant and grounded in real-world needs.

As this realist review will collect previously published data and will not involve human or animal participants, no ethical approval is required. Since this manuscript is a review protocol, no datasets were generated or analysed. All data extraction forms will be made available as part of the publication of the realist review.

Systematic review registration PROSPERO 2025 CRD420251011954.

Dates of the study: September 2025 to September 2026.