Mental disorders and excess mortality: a systematic review protocol

BackgroundThere is developing evidence of excess mortality among people with mental disorders. This protocol presents the methodology to undertake a systematic review to definitively examine the current evidence on the risk of all-cause and cause-specific mortality in people with mental disorders (mood, anxiety, substance use, eating, personality and psychotic disorders) compared with populations without mental disorders in broadly representative studies of general populations worldwide. In addition, we seek to understand whether the excess mortality has increased further over time, and if the COVID-19 pandemic exacerbated the excess mortality in people with mental disorders.MethodsA systematic review of cohort studies will be conducted. The search strategy to yield peer-reviewed (in Medline Complete, CINAHL Complete, Embase and APA PsycInfo) and published grey literature will be developed in consultation with a liaison librarian. A preliminary scope of peer-reviewed literature in Medline Complete using the EBSCOhost platform was conducted on 20 November 2023. Epidemiological cohort or case-control studies will be eligible if they examine (1) diagnoses of mental disorders (according to the Diagnostic and Statistical Manual of Mental Disorders and the International Classification of Diseases classification systems) and (2) risk of all-cause and/or cause-specific mortality. A critical appraisal of the included studies will be undertaken. A synthesis of the findings will include the characteristics of the included studies, critical appraisal and a summary of the key findings in texts and visually in tables. Where appropriate, meta-analyses and subgroup analyses will be performed.Ethics and disseminationThis study is exempt from ethics approval, as it does not include identifiable human data. The outcomes of the proposed review will be shared in national/international conferences, published in a peer-reviewed journal and disseminated to new and existing networks.PROSPERO registration numberCRD42023477494.