CARDIFF, Wales, Sept. 8 (UPI) -- The risk of psychosis is higher in cities than in rural areas and that may be a reflection of increased social fragmentation in cities, Welsh researchers said.

Stanley Zammit of Cardiff University in Wales and colleagues studied a total of 203,829 people living in Sweden and found 328 had a record of having been admitted with a diagnosis of schizophrenia, 741 with other non-affective psychoses, 355 with affective psychoses and 953 with other psychoses.

"An association between urbanicity and non-affective psychosis was explained by higher-level characteristics, primarily school-level social fragmentation," Zammit said in a statement. "Social fragmentation was the most important area characteristic that explained the increased risk of psychosis in individuals brought up in cities."

The findings, published in the journal Archives of General Psychiatry, 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.