The incidence of non-affective psychotic disorders in low and middle-income countries: a systematic review and meta-analysis

Abstract

Purpose 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). Methods 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 May 2022; 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). Results We retrieved 11 421 records, of which 23 citations met inclusion criteria from 18 unique studies across 19 settings in 10 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. Conclusion 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 NAPD is now urgently required.

Prevalence of mental disorders in South Asia: A systematic review of reviews

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The social determinants of mental health and disorder: evidence, prevention and recommendations

“…In LMIC settings, the reasons for this may be self‐evident, since limited resources may mean political prioritization of other vital issues. Recent reviews have highlighted the evidence gap in incidence and prevalence estimates of psychiatric disorders between HIC and LMIC settings 462 . In HIC settings, the lack of routine data on psychiatric morbidity in the population is sometimes surprising.…”

Treated incidence of first episode psychosis in Sinop, Turkey: results of a 4-year admission-based study – SINOPsy

“…Despite two-to-threefold variation in incidence rates across study centres, the results have long been interpreted as evidence that psychotic disorders are similarly prevalent in different parts of the world (McGrath, 2005). This interpretation has subsequently been challenged by systematic reviews, meta-analyses, and new multisite studies (Bastien et al, 2023;Jongsma et al, 2018;McGrath et al, 2004). The variations in incidence may provide clues to the aetiology of psychotic disorders, particularly the types of environments that increase or differentiate the risk for the disorder.…”

“…The variations in incidence may provide clues to the aetiology of psychotic disorders, particularly the types of environments that increase or differentiate the risk for the disorder. In the meta-analysis of rates from low-and middle-income countries, estimates were based on very limited settings, highlighting the need for new studies in non-Western countries (Bastien et al, 2023).…”