Incidence And Socio-Demographic/Clinical Characteristics Of Psychotic Disorders In India, Nigeria And Trinidad: Preliminary Baseline Findings From Intrepid Ii

Abstract Background The incidence, presentation, and course of psychotic disorders are highly variable across populations. A recent review noted a lack of evidence from low- and middle-income countries in the global South, where around 85% of the world’s population lives. Robust population-based data from these contexts are needed to better understand the sources of variation in psychotic disorders. INTREPID II is a multi-country programme comprising incidence, case-control, and follow-up studies of psychotic disorders in three diverse catchment areas with populations at risk of ~ 500,000 in Tamil Nadu (India), Oyo state (Nigeria), and northern Trinidad. Here, using baseline data from the initial 15 months, we present findings on variations in incidence and clinical presentation. Methods Baseline recruitment and assessment is ongoing. In each site individuals with an untreated psychotic disorder are identified through a comprehensive case detection system that includes professional, folk, and popular sectors. Inclusion criteria are age of 18–64, resident in catchment area, presence of a ICD-10 psychotic disorder, and no more than one continuous month of treatment with antipsychotic medication prior to the start of case identification. At baseline, detailed data on demographic and clinical characteristics and putative risk factors are collected using established tools. Results In the first 15 months, we identified 614 cases (199 in India, 92 in Nigeria, and 264 in Trinidad). There was wide variation in where cases were identified: In India, 9% via professional services and 91% via the popular sector (i.e., in the community); In Nigeria, 33% via professional services and 63% via the folk sector (traditional and religious service providers); In Trinidad, 98% via professional services. Further, there were notable variations in incidence and sociodemographic and clinical characteristics. Age-adjusted rates were highest in Trinidad (men: 47.1, 95% CI 39.8–55.4; women: 38.7, 95% CI 32.0–46.3) compared with India (men: 23.0, 95% CI 18.4–28.4; women: 30.2, 95% CI 24.9–36.4) and Nigeria (men: 13.0, 95% CI 9.5–17.2; women: 12.4, 95% CI 9.0–16.6). The proportion with age of onset before 29 years was higher in Trinidad (74%) compared to Nigeria (45%) and India (36%). Among those on whom full data are currently available (n, 327), more in Nigeria were assigned a diagnosis of schizophrenia (63%) than in India (46%) and Trinidad (42%). Median duration of untreated psychosis was was longer in India (5.1 years, IQR 1.9–13.6) than in Nigeria (1.5 years, IQR 0.1–4.1) and Trinidad (2.6 years, IQR 0.3–15.2). However, an insidious onset (i.e., gradual emergence of symptoms over several months) was more common in Trinidad (50% of cases) than in India (28%) and Nigeria (14%). Education levels were lower in India (31% completed secondary education or higher) than in Nigeria (74%) or Trinidad (68%). However, the proportion of cases who were married or in a steady relationship was similar in all sites (India: 42%, Nigeria: 38%, Trinidad: 38%), as was the proportion who were unemployed (India: 48%, Nigeria: 55%, Trinidad: 51%). Discussion In initial analyses, we found evidence that the incidence and presentation of psychoses varied by site, findings that both further highlight the heterogeneity of psychoses across contexts and challenge assumptions about the basic epidemiology based on findings from the global North. For example, the data from our India site suggest higher rates among women and a later age of onset than commonly supposed. Our findings also show that many people with psychotic disorders in these settings are untreated for long periods, indicating an urgent need to develop more accessible services.