The Incidence of Non-Affective Psychotic Disorders in Low and Middle Income Countries: A Systematic Review and Meta-Analysis

Abstract

Global understanding of the epidemiological landscape of non-affective psychotic disorders [NAPD] is predominantly based on studies from high-income countries. We sought to systematically review and meta-analyse all incidence studies conducted in low- and middle-income countries [LMICs]. We systematically searched four databases using terms for NAPD, incidence and LMICs. Citations were eligible for inclusion if: published between 1 January 1960 and 31 December 2019; wholly or partially conducted in an LMIC, and; containing data on NAPD incidence in the general adult population. Two independent raters assessed study quality according to previously published criteria. We conducted a narrative synthesis and random-effects meta-analyses where sufficient studies were available (N≥5). We retrieved 6 600 records, of which 19 citations met inclusion criteria from 15 unique studies across 17 settings in 9 LMICs. Median study quality was 4 out of 7 (interquartile range: 3-6). The crude incidence of NAPD varied around 4·2 times, from 10·0 per 100 000 person-years (95% confidence interval [CI]: 8·7–11·4) in Brazil to 42·0 (95%CI: 32·2–54·8) in India, with marked heterogeneity in methodologies and rates. Our 60-year review highlights the dearth of robust evidence on the incidence of psychotic disorders in LMICs. Without reliable, contemporary estimates of this fundamental cornerstone of population health, it is impossible to understand the true burden, distribution or causes of psychotic disorders in over 87% of the world’s population. A new, more equitable global mental health evidence base for psychosis is now urgently required. Registration Information: Preregistration on PROSPERO (reference: CRD42020179678). Funding Information: Funding for this project was obtained as part of the Delineating the Epidemiology of first episode Psychosis In Chile: a nationwide register study of 30 000 incident cases between 2005 and 2018 (the DEPICt study), under the UCL ‘Grand Challenges’ small grants scheme (2019). RJBB, JBK and HEJ are supported by the National Institute for Health Research University College London Hospital Biomedical Research Centre. LV acknowledges financial support from the National Institute for Health Research (NIHR) Biomedical Research Centre for Mental Health at South London and Maudsley NHS Foundation Trust and King’s College London. Declaration of Interests: None to declare.