It might be a 'concrete jungle' in the city, but the brains of urban-dwellers could do with more of the real thing, according to a study published in Nature today. It seems the stereotypes of maddening city crowds, and the calming country, are based on more than just wishful thinking. This new research suggests that they may, in fact, have a real basis in the brain. That would help explain multiple studies showing greater mental distress, for those living in cities - and may point to better ways to build environments that support mental wellbeing.

'Previous findings have shown that the risk for anxiety disorders is 21 percent higher for people from the city, who also have a 39 percent increase for mood disorders," said co-author Jens Pruessner, from the Douglas Mental Health University Institute. 'In addition, the incidence for schizophrenia is almost doubled for individuals who are born and brought up in cities. These values are a cause for concern and determining the biology behind this is the first step to remedy the trend.'

The research was conducted by an international team, including members of Montreal's Douglas Mental Health University Institute and the Central Institute of Mental Health, Mannheim, in Germany. The team were using the powerful mental probing tool - fMRI, or functional magnetic imaging - to capture how the brains of city-dwellers and country-folk worked under duress.

By applying a series of simple arithmetic challenges, under increasing threat of social punishment, the team were hoping to spot which areas of the brain were being lit up. The participants were either confirmed urbanites, who had spent their lives in the city, recent city-dwellers or country-born-and-bred. And the results did indeed show that those parts of the brain that controlled stress reacted differently in each group.

City dwellers had the largest stress response in the amygdala - a part of the brain which helps regulate moods and emotions. But for those of an urban upbringing, it was found that the activities generated a reaction in the cingulate cortex, which regulates negative affects and stress. These real differences in brain activity could lie behind the significantly higher level of mental disorder seen amongst urban populations.

'These findings suggest that different brain regions are sensitive to the experience of city living during different times across the lifespan,' says Pruessner. 'Future studies need to clarify the link between psychopathology and these affects in individuals with mental disorders. 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.'