Trauma makes brains more reactive to fear

A Cornell University study found that the brains of people who were geographically closer to a disaster at the time it took place, such as the collapse of the World Trade Center, react more strongly to emotional triggers--even if they otherwise seem to have healed fully.

Researchers found that three years after 9/11, people closer to ground zero tended to still experience lingering symptoms (bad dreams, jumpiness, thinking about the incident, and avoiding the site of the trauma), though they weren't severe enough to be diagnosed as post-traumatic stress disorder or major depression.

Using functional magnetic resonance imaging to see how people's brains responded to photographs of fearful versus calm faces, the scans of 11 people who were within 1.5 miles of the World Trade Center on September 11, 2001, were compared with those who were living more than 200 miles away at the time; none of the subjects had psychiatric disorders.

"These people appear to be doing OK, but they may indeed be having more sensitive responses to upsetting stimuli," said Elise Temple, a coauthor and assistant professor of human development at Cornell, in a statement.

And the brains of people with lingering symptoms had significantly more emotional reactions when shown photographs of fearful faces. The kinds of changes that these traumas cause in the brain create vulnerability to developing future mental disorders, say the researchers.