WEDNESDAY, June 22 (HealthDay News) -- People who are born and raised in cities have a greater lifetime risk for anxiety and mood disorders due to the impact that city living appears to have on two brain regions that regulate emotion and stress, a new international study indicates.

The findings may lead to new ways to improve the quality of life for city dwellers, according to the researchers.

Previous studies found that urban residents have a 21 percent increased risk for anxiety disorders and a 39 percent increased risk for mood disorders. They also have nearly twice the rate of schizophrenia compared to people who don't live in cities, said study co-author Jens Pruessner, of the Douglas Mental Health University Institute in Montreal.

He and his colleagues in Germany used functional MRI to study the brain activity of healthy volunteers from urban and rural areas. They found that city dwellers had greater stress responses in the amygdala, an area of the brain involved in emotional regulation and mood.

The researchers also found that being raised in the city was associated with activity in the cingulate cortex, which is involved in regulation of negative mood and stress.

The study appears in the current issue of the journal Nature.

"These findings suggest that different brain regions are sensitive to the experience of city living during different times across the lifespan," Pruessner said in a Douglas news release. "These findings contribute to our understanding of urban environmental risk for mental disorders and health in general. They further point to a new approach to interface social sciences, neurosciences and public policy to respond to the major health challenge of urbanization."

Pruessner added that more studies were needed to expand on the findings.

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