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. 2023 Oct;53(14):6459-6467.
doi: 10.1017/S0033291722003749. Epub 2023 Jan 16.

Urbanicity and rates of untreated psychotic disorders in three diverse settings in the Global South

Tessa Roberts  1   2 , Ezra Susser  3   4 , Joni Lee Pow  5 , Casswina Donald  5 , Sujit John  6 , Vijaya Raghavan  6 , Olatunde Ayinde  7 , Bola Olley  7 , Georgina Miguel Esponda  1 , Joseph Lam  8 , Robin M Murray  9 , Alex Cohen  10 , Helen A Weiss  11 , Gerard Hutchinson  5 , Rangaswamy Thara  6 , Oye Gureje  7 , Jonathan Burns  12 ; INTREPID Group; Craig Morgan  1   2   13
Collaborators, Affiliations

Urbanicity and rates of untreated psychotic disorders in three diverse settings in the Global South

Tessa Roberts et al. Psychol Med. 2023 Oct.

Abstract

Background: Extensive evidence indicates that rates of psychotic disorder are elevated in more urban compared with less urban areas, but this evidence largely originates from Northern Europe. It is unclear whether the same association holds globally. This study examined the association between urban residence and rates of psychotic disorder in catchment areas in India (Kancheepuram, Tamil Nadu), Nigeria (Ibadan, Oyo), and Northern Trinidad.

Methods: Comprehensive case detection systems were developed based on extensive pilot work to identify individuals aged 18-64 with previously untreated psychotic disorders residing in each catchment area (May 2018-April/May/July 2020). Area of residence and basic demographic details were collected for eligible cases. We compared rates of psychotic disorder in the more v. less urban administrative areas within each catchment area, based on all cases detected, and repeated these analyses while restricting to recent onset cases (<2 years/<5 years).

Results: We found evidence of higher overall rates of psychosis in more urban areas within the Trinidadian catchment area (IRR: 3.24, 95% CI 2.68-3.91), an inverse association in the Nigerian catchment area (IRR: 0.68, 95% CI 0.51-0.91) and no association in the Indian catchment area (IRR: 1.18, 95% CI 0.93-1.52). When restricting to recent onset cases, we found a modest positive association in the Indian catchment area.

Conclusions: This study suggests that urbanicity is associated with higher rates of psychotic disorder in some but not all contexts outside of Northern Europe. Future studies should test candidate mechanisms that may underlie the associations observed, such as exposure to violence.

Keywords: Epidemiology; global mental health; incidence; psychosis; schizophrenia; urbanicity.

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Conflict of interest statement

R. M. M. has received payment for lectures from Janssen, Sunovian, Otsuka, Lundbeck, Angelini and Rekordati.

Figures

Fig. 1.
Fig. 1.
(a–c). Maps of INTREPID II catchment areas in India, Nigeria and Trinidad. Black borders indicate the boundaries of the total catchment area in each setting and the administrative areas within these. Green, yellow and pink voxels indicate level of urbanicity according to the GHS-SMOD classification system using the Degree of Urbanisation (DEGURBA) methodology, developed by EuroSAT (Florczyk et al., ; Joint Research Centre (JRC) European Commission, & Center for International Earth Science Information Network – CIESIN – Columbia University, 2021). EuroSAT's DEGURBA methodology. This applies a set of decision rules that consider population and built-up area densities derived from the GHS-POP and GHS-BUILT data sets, which use spatial data mining technologies that rely on a combination of fine-scale satellite image data streams, census data, and crowd sourced or volunteered geographic information sources (see https://sedac.ciesin.columbia.edu/data/set/ghsl-population-built-up-estimates-degree-urban-smod). Pink indicates urban areas (Class 30: ‘Urban Centre’, Class 23: ‘Dense Urban Cluster’, and Class 22: ‘Semi-dense Urban Cluster’), yellow indicates peri-urban areas (Class 21: ‘Suburban or peri-urban’), while green indicates rural areas (Class 13: ‘Rural cluster’, Class 12: ‘Low Density Rural’, and Class 11: ‘Very low density rural’).
Fig. 2.
Fig. 2.
(a–c). Rate of psychosis and population density by area.
See this image and copyright information in PMC

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