The world's urban population is growing fast and it's estimated that five billion people will live in cities by 2030, according to data from the United Nations. Such rapid urbanization has spurred research on the positive and negative effects of city living on individual health. A thought-provoking entry published today on the Scientific American blog The Scicurious Brain examines recent findings on how city life may affect the brain's response to stress:
... there is also some evidence that living in a city can "bring on" mental disorders. While many mental disorders are thought to have a genetic component to some degree, the addition of stress may be able to bring out an underlying mental illness. And of course, cities are stressful. Specifically, cities produce social stress, the stress of living around and being seen (or feeling you're being seen) by lots of people, constantly.
The authors of this study wanted to look at how urban upbringing, and living in an urban environment currently, affected the way people processed social stress. They took a bunch of healthy volunteers, half from the city, and half from the country (pretty small numbers here, but that's usual in these studies). They stuck them in an fMRI and examined their brain activity at baseline and during a social stress test. For the social stress test, they had the participants perform difficult arithmetic under time pressure, with a scientist telling them in an annoyed voice when they got it wrong. And they manipulated the test to make sure that the participants got it wrong most of the time. They looked at brain activity, as well as heart rate, blood pressure, and a stress hormone called cortisol. They even asked the subjects how stressed out they felt. And then they looked at their brains.
The study results showed the brains of people who lived in urban areas reacted more strongly to stress compared to others who lived in small towns. The full blog post is worth reading and includes a detailed discussion of the research, as well as the author's analysis questioning the research.
Previously: Can stress increase risk of neurodegenerative diseases?, No surprise here: Anger and stress are bad for your health, Robert Sapolsky on stress and your health and Out-of-office autoreply: Reaping the benefits of nature
Photo by Aires Almeida