Weaving Causal Explanations of Schizophrenia in Urban Areas: The Role of Gene-Environment Selection

Urbanization and psychosis: an update of recent evidence

PURPOSE OF REVIEW

Urbanization, a complex global phenomenon, has a significant bearing on schizophrenia/psychosis burden through various socioeconomic and environmental factors. This review focuses on recent evidence (2019-2023) linking urbanization, schizophrenia, and the role of green space.

RECENT FINDINGS

This review analyzed 43 articles that examined the correlation between urban birth or upbringing, urban living (urbanicity), and various schizophrenia/psychosis-related outcomes such as incidence, psychotic experiences, etc. The studies showed differing results across geographical locations. Socioeconomic factors like area deprivation, migrant status (ethnic density) and social fragmentation were independently associated with the risk of schizophrenia/psychosis irrespective of urbanicity. More recently, environmental factors such as green space reduction and air pollution have been explored in urban living conditions and were positively associated with an increased risk of schizophrenia/psychosis.

SUMMARY

There is a need for further investigation in low and middle-income countries. The impact of urbanization-related factors and green space on the risk of schizophrenia/psychosis calls for appropriate governmental commitments toward structured and healthy urban planning.

Urban upbringing and psychotic experiences in the United States: A racial and geographic comparison

Urban upbringing has been associated with greater risk for psychotic experiences, though research is needed to confirm whether this is true in the U.S., and whether the association depends on race, type of experience, and region of the country. We analyzed data from the National Comorbidity Survey Replication (White respondents only) and the National Survey of American Life (Black respondents). Multivariable logistic regression models found that urban upbringing was not significantly associated with lifetime psychotic experiences for Whites, but was significantly associated with lower odds for Blacks, adjusting for socio-demographic covariates and common mental disorders. Rural upbringing was associated with greater odds of lifetime auditory hallucinatory experiences for Blacks. Exploratory analyses suggested growing up in a large city or 'other' environment were associated with greater odds of lifetime psychotic experiences among Whites currently residing in the Northeast, but lower odds among Whites residing in the South. For Blacks currently residing in the West, rural upbringing was associated with significantly greater odds of lifetime psychotic experiences when compared with growing up in a large city. White and Blacks may have different lived experiences in urban and rural settings, calling for more race- and location- specific research to explain these diverging patterns.