Welsh researchers said the risk of psychosis seems to be higher in cities than in rural areas. This may be a reflection of increased social fragmentation in cities.

Stanley Zammit of Cardiff University in Wales and his colleagues studied a sample size of 203,829 people living in Sweden. The study revealed that 328 people had a record of having been admitted with schizophrenia, 741 with other non-affective psychoses, 355 with affective psychoses and 953 with other psychoses.

Zammit said in a statement that primarily school-level social fragmentation is an important area that leads to increased risk of psychosis in individuals brought up in cities.

The findings have been published in the journal Archives of General Psychiatry. The study highlight the concern that physical integration alone is not sufficient, but some of the positive characteristics traditionally conferred by segregation -- such as a localized sense of safety, cohesion and community spirit -- must also be maintained to enhance the mental health of individuals within the population.