“ALICE PARK” - Stressed in the City: How Urban Life May Change Your Brain

By ALICE PARK Wednesday, June 22, 2011

 http://healthland.time.com/2011/06/22/stressed-in-the-city-how-urban-life-may-change-your-brain/

I live in New York City, and for me, there's nothing that compares to its culture, energy and convenience. I'm not alone in feeling this way — more than half of the world's population now lives in urban areas.

But I also know that when it comes to mental health, the urban lifestyle may not be such a good thing. City dwellers tend to be more stressed and have higher levels of mood disorders and psychotic illnesses such as schizophrenia than those living in rural or suburban areas. And now researchers say they have uncovered certain changes in brain activity that could potentially help explain why.

In an international study, researchers at University of Heidelberg and the Douglas Mental Health University Institute at McGill University report in the journal Nature that people who live or were raised in cities show distinct differences in activity in certain brain regions than those who aren't city dwellers.

Those who currently live in the city, for example, showed higher activation the amygdala, the brain region that regulates emotions such as anxiety and fear. The amygdala is most often called into action under situations of stress or threat, and the data suggest that city dwellers' brains have a more sensitive, hair-trigger response to such situations, at least when compared with those living in the suburbs or more rural areas.

The study also found that people who were raised in the city during their first 15 years of life were more likely to show increased activation in another brain region, a more global regulator of stress known as the anterior cingulate. In these individuals, the change appears to be more permanent than in people who move to cities later in life, says Jens Pruessner, director of aging and Alzheimer's research at the Douglas Institute and one of the study's co-authors, because it occurs during an important period of development. Living in the city during your early years "means you will become more alert to [stress] situations via the anterior cingulate for the rest of your life," he says.

The researchers came to their conclusions after conducting a stress test on volunteers while their brains were imaged with functional MRI to detect which areas of the brain were more or less active when the participants felt stressed. The stress was applied by asking people to solve difficult math problems, either under time pressure or while enduring criticism from researchers for their bad performance.

The research team then correlated the participants' brain scan results with information they provided about where they currently lived or where they were raised. Activation of the amygdala increased in step with the population density of participants' home towns: from rural areas to small cities to large urban settings.

The researchers think it is the social aspects of urban living — the stress of living and dealing with lots of people, and feeling more anxiety, fear and threat as a result — more so than other urban factors like pollution or noise that explains the higher stress-related brain responses among the city dwellers.

Although it would seem that the more people were faced with stress, the more they might tolerate these annoyances and even become immune to them — thus lowering, rather than increasing their threshold for triggering the stress response — the new findings suggest otherwise. Even after years of city living, people remained highly alert and anxious, which indicates that the stresses of city life may be both constant and diverse and not easy to adapt to.

"City people may never really face the same stresses," says Pruessner. "Even though the type of stress may be similar, such as time pressure or being stuck in a commute or meeting a deadline, it's always distinct enough that you don't have the chance to habituate to them."

So what does this mean for avid city livers like me? I'm not giving up my urban lifestyle, but I may have to balance the high-energy hum of city activity with more downtime. "In general when it comes to stress, it's important to keep a balance," says Pruessner. "These results suggest the need to keep things in balance so after a period of working hard, you balance that with a period of off-time as well."

That sounds good, but in the city, that's a lot easier said than done.