Outcomes frequently specified in Cochrane reviews of community-based psychosocial interventions for adults with severe mental illness: A systematic search and narrative synthesis

Background Outcome selection in intervention studies is a critical issue for synthesizing evidence. This study is aimed to investigate outcomes used in Cochrane reviews assessing community-based psychosocial interventions for adults with severe mental illness. Methods Cochrane reviews that evaluated a community-based psychosocial intervention for adults with severe mental illness were searched electronically and manually. We extracted all outcomes specified in the Methods section in each Cochrane review. Outcomes that represent the same concept and context were synthesized into an outcome term. Outcome terms were categorized according to the existing taxonomy. Results We included 33 Cochrane reviews. Of the 216 outcome terms identified, 13 were used in more than half of the reviews: quality of life, mental state, admission to hospital, economic outcome, leaving the study early, social functioning, satisfaction, global state, relapse, adverse events/effects, carer satisfaction, employment, and duration of admission. Most outcome terms were categorized into the life impact core area (55%), followed by the resource use area (21%). Conclusions Our study provides a candidate outcome list for developing a core outcome set for severe mental illness and offers a basis for comparison for future outcome investigation on mental health research.