REalist Synthesis Of non-pharmacologicaL interVEntions for antipsychotic-induced weight gain (RESOLVE) in people living with severe mental illness

Abstract Introduction Antipsychotic medications are used to treat individuals with severe mental illness. These medications are associated with rapid weight gain and several physical and mental risk factors. Early, proactive weight management is necessary to pre-empt these risk factors. Methods A realist review was conducted to identify contextual factors and underlying mechanisms associated with effective, non-pharmacological weight management interventions for this population. A stakeholder group of practitioners and a stakeholder group of individuals with lived experience and their family carers were integral to the review process. Results The realist review consisted of 58 documents where 41 papers were intervention studies of non-pharmacological weight management interventions for individuals with severe mental illness. Weight management interventions typically included nutrition counseling, physical activity and behaviour therapies offered over different time ranges by combinations of facilitators. Follow-up was rarely reported, and these intervention studies yielded mixed outcomes for weight loss/weight gain prevention, decreased clinical risk indicators and improved physical and mental health. Review documents and stakeholder discussions were used to construct a programme theory and 12 testable context-mechanism-outcome configurations. Review findings emphasise the significant effect of stigma/double stigma on individuals with severe mental illness and weight gain. Therapeutic practitioner relationships, family and peer support contribute to individuals' engagement with healthy behaviours. Conclusions Multi-country non-pharmacological interventions for weight management have had mixed results. This realist review identified characteristics and potential mechanisms that may make a significant, positive difference to individuals with severe mental illness. A realist evaluation with primary data is currently underway.