More than half the world’s population now lives in urban settings, and by 2050 the percentage is expected to rise to 70%. Because cities will be home to so many, it’s essential to better understand the health benefits and risks of urban living.

A 2010 study by the Central Institute of Mental Health in Germany and McGill University in Canada, published in the journal Nature, “City Living and Urban Upbringing Affect Neural Social Stress Processing in Humans,” used computerized stress tests and MRI scans, coupled with biological data on subjects’ geographical histories to determine the impacts of living in cities on the brain’s processes for dealing with stress.

Results of the study included:

• Meta-analysis of previous studies show that city dwellers have a 21% greater risk for anxiety disorders and a 39% increased likelihood of mood disorders.
• MRI scans showed that increased exposure to urban environments was associated with increased activity in the brain’s amygdala region, which is involved in emotions such as fear and the release of stress-related hormones.
• For those who lived in cities for the first 15 years of life, the MRI showed increased activity in the perigenual anterior cingulate cortex, which plays a role in regulating the amygdala region of the brain. Those raised in the city are thus more likely to have a permanently raised sensitivity to stress than those who moved there later in life.

While there are limitations to the study, including its small size, the researchers state that its findings “reveal neural effects of urban upbringing and habitation on social stress processing in humans.”

Tags: mental health, cognition