Living and working in the city can be very stressful, both physically and mentally. I can personally attest to this, as my day begins with a stressful commute into New York City and continues while I treat sick patients in a very busy hospital. It has been shown that life in a big urban center increases the risk of developing emotional problems and mental disorders. A person that lives in a big city has two to three times the likelihood of developing schizophrenia as compared to a person living in a rural setting. There is also a higher incidence of anxiety disorder and major depression in individuals who live and work in big cities. In addition, it has been shown that the larger the city, the greater the risk of psychiatric illness which suggests that there is a dose response. Please don’t misunderstand me – there is a long list of advantages to living in a big city and these include excellent restaurants, nightlife, theaters, culture, high energy, and easy accessibility to transportation. All these benefits come with an added risk, though. In today’s issue of Nature, researchers lead by Dr. Andreas Meyer-Lindenberg from the University of Heidelberg in Germany describe results that show city life causes changes in the stress center of the brain. In their experiments, the researchers used functional magnetic resonance imaging (MRI) on students performing arithmetic exams under stressful situations. In addition, the students were pressured with both time and derogatory statements while attempting to solve the mathematical problems. The functional MRI images were evaluated based upon information provided by the students regarding where they were raised and where they currently lived. The researchers found a remarkable correlation. The students who currently lived in a major city showed higher activation of a brain region called the amygdala. The amygdala is a region of the brain that is involved in regulating anxiety, fear, worry, and other stress related emotions. This information suggests that residents of the city have a more sensitive response to stressful situations compared to their rural counterparts. The study also showed that individuals who were raised in the city during their adolescence showed higher activation of a brain region known as the perigenual anterior cingulate cortex (PACC). The PACC is an important brain region for the regulation of stress, emotion, and negative affect. The PACC is also involved in regulation of amygdala activity and together they form a neural circuit in the brain involved in the regulation of emotion and stress. These results suggest that city living causes changes in the brain that may be related to the increased incidence of mental illness among city dwellers. The authors wrote, “Our results identify distinct neural mechanisms for an established environmental risk factor, link the urban environment for the first time to social stress processing, suggest that brain regions differ in vulnerability to this risk factor across the lifespan, and indicate that experimental interrogation of epidemiological associations is a promising strategy in social neuroscience”. Future research will focus on the particular aspects of city life that cause these brain changes and how changing city environments can help alleviate these anxiety provoking responses.
Florian Lederbogen et al. “City living and urban upbringing affect neural social stress processing in humans” Nature 474, 498-501 published online 22 June 2011.