From idealist to realist - designing and implementing shared decision-making interventions in the choice of antipsychotic prescription in people living with psychosis (SHAPE): a realist review (Part 2 - designing SDM interventions: optimising design and local implementation)

Background
Shared decision-making (SDM) implementation remains limited in psychosis management, particularly within antipsychotic prescribing. When and why prescribers engage in SDM within these contexts is largely unknown. Part 2 of this 2-part realist review aimed to understand what SDM intervention strategies and local implementation contexts are responsible for successful prescriber engagement and why.

Study design
CINAHL Plus, Cochrane Library, Embase, PsycINFO, PubMed, Scopus, Sociological Abstracts, Web of Science, and Google Scholar were searched for evidence to develop realist program theories explaining relationships between meso- and micro-level contexts and impact on prescriber behaviors.

Study results
From 106 included documents, 5 program theories were developed explaining mechanisms responsible for increasing prescriber engagement with desired behaviors, alongside facilitative features within service delivery contexts and workforce development. Key mechanisms included reducing prescriber fear of sole responsibility for harm, reducing the perceived burden of SDM, increasing prescriber confidence in their ability to productively negotiate treatment consultations and their confidence to safely increase patient autonomy within decision-making. These mechanisms should be the focus of those interested in designing SDM interventions to increase prescriber engagement and those responsible for translating results of effective interventions into real-world settings to ensure facilitative contexts are maintained.

Conclusion
Intervention strategies that should be prioritized for scale-up include attempting SDM within existing therapeutic relationships, adopting a multidisciplinary team (MDT) responsibility for SDM implementation, and workforce training in skillsets required of effective SDM application. Efforts to standardize psychosis care via MDTs and systematically reduce discontinuity and fragmentation of care are required at policy-level.