Shared decision-making interventions in the choice of antipsychotic prescription in people living with psychosis (SHAPE): protocol for a realist review

Background: Shared decision-making (SDM) has yet to be successfully adopted into routine use in psychiatric settings amongst people living with severe mental illnesses. Suboptimal rates of SDM are particularly prominent amongst patients with psychotic illnesses during antipsychotic treatment choices. Many interventions have been assessed for their efficacy in improving SDM within this context, although results have been variable and inconsistent. Aims: To generate an in-depth understanding of how, why, for whom, and to what extent interventions facilitating the application of SDM during choice of antipsychotic drug treatment work and the impact of contextual factors on intervention effectiveness. Methods: This review will use realist review methodology to provide a causal understanding of how and why interventions work when implementing SDM during choice of antipsychotic treatment. The review will take place over five stages; (1) Locating existing theories, (2) Searching for evidence, (3) Selecting articles, (4) Extracting and organising data and (5) Synthesizing evidence and drawing conclusions. An understanding of how and why interventions work will be achieved by developing realist programme theories on intervention effectiveness through iterative literature reviews and engaging with various stakeholder groups, including patient, clinician and carer representatives. Discussion: This is the first realist review aiming to identify generative mechanisms explaining how and why successful interventions aimed at improving SDM within the parameters outlined work and in which contexts desired outcomes are most likely to be achieved. Review findings will include suggestions for clinicians, policy and decision-makers about the most promising interventions to pursue and their ideal attributes.