Question Is urban living associated with elevated odds for psychotic experiences or psychotic disorder in low- and middle-income countries?
Findings In this cross-sectional epidemiological study of 42 countries and 215 682 participants, urban residence was not associated with increased odds of psychotic experiences or psychotic disorders.
Meaning The association between urban living and psychosis, widely replicated in high-income countries, may not generalize to low- and middle-income countries, where 80% of the world’s population resides.
Importance Urban residence is one of the most well-established risk factors for psychotic disorder, but most evidence comes from a small group of high-income countries.
Objective To determine whether urban living is associated with greater odds for psychosis in low- and middle-income countries (LMICs).
Design, Setting, and Participants This international population-based study used cross-sectional survey data collected as part of the World Health Organization (WHO) World Health Survey from May 2, 2002, through December 31, 2004. Participants included nationally representative general population probability samples of adults (≥18 years) residing in 42 LMICs (N = 215 682). Data were analyzed from November 20 through December 5, 2017.
Exposures Urban vs nonurban residence, determined by the WHO based on national data.
Main Outcomes and Measures Psychotic experiences, assessed using the WHO Composite International Diagnostic Interview psychosis screen, and self-reported lifetime history of a diagnosis of a psychotic disorder.
Results Among the 215 682 participants (50.8% women and 49.2% men; mean [SD] age, 37.9 [15.7] years), urban residence was not associated with psychotic experiences (odds ratio [OR], 0.99; 95% CI, 0.89-1.11) or psychotic disorder (OR, 0.89; 95% CI, 0.76-1.06). Results of all pooled analyses and meta-analyses of within-country effects approached a null effect, with an overall OR of 0.97 (95% CI, 0.87-1.07), OR for low-income countries of 0.98 (95% CI, 0.82-1.15), and OR for middle-income countries of 0.96 (95% CI, 0.84-1.09) for psychotic experiences and an overall OR of 0.92 (95% CI, 0.73-1.16), OR for low-income countries of 0.92 (95% CI, 0.66-1.27), and OR for middle-income countries of 0.92 (95% CI, 0.67-1.27) for psychotic disorder.
Conclusions and Relevance Our results provide evidence that urbanicity, a well-established risk factor for psychosis, may not be associated with elevated odds for psychosis in developing countries. This finding may provide better understanding of the mechanisms by which urban living may contribute to psychosis risk in high-income countries, because urban-rural patterns of cannabis use, racial discrimination, and socioeconomic disparities may vary between developing and developed nations.