Association Between Urban Upbringing and Cortical Gyrification in Persons with Schizophrenia

Many studies suggest that urban upbringing might increase the risk of developing schizophrenia (SCZ). However, the precise brain changes associated with urban upbringing remain poorly understood. In this study, we investigated how urban upbringing might influence cortical gyrification, a brain feature that reflects early structural development.

The study included 70 Healthy Controls (HC) and 87 individuals diagnosed with SCZ, all aged between 18 and 50 years. Participants and their caregivers were interviewed to collect information about birthplace and upbringing location. Based on data from the Indian Census (1971-2011), upbringing locations were categorized into three groups: rural, town, and city. An urbanicity index was calculated using a previously established method. Brain anatomical MRI images were processed using FreeSurfer. Regression analysis was conducted using the QDEC interface, with the gyrification index (GI) as the dependent variable, and urbanicity index, sex, and age as predictors.

In the entire sample, a significant positive association was observed between the urbanicity index and the GI in the left supramarginal gyrus (BA40; p = .001), left rostral middle frontal gyrus (BA10; p < .001), and both the left and right lateral occipital gyri (BA18; p = .001). Additionally, a significant interaction effect between the diagnosis and urbanicity index was found in multiple brain regions.

These findings suggest that urban living has a significant influence on brain development. Identifying such risk factors and underlying mechanisms could help develop prevention strategies and guide improvements in urban planning.