“We’ve been finding that of these children who start out very fearful, about 50 percent of them end up being very nervous and socially fearful when they are in preschool and then school age,” Fox said. “Some of those kids, not a large percentage, go onto develop anxiety.”
Although not all of the children that displayed signs of an anxious temperament went on to develop the disorder, Fox’s research proved they all had one common trait: a hyperactive amygdala.
Functional MRIs of test subjects showed the amygdala, a brain structure the size of their a thumbnail that determines the body’s response to threats, increased in activity when unfamiliar situations were presented.
“We can put someone into this MRI machine, show them stimuli and see whether or not the amygdala of these temperamentally fearful children is more active than that of children who are not fearful.”
Because subjects have to sit still for the duration of an MRI, Fox did not collect data on his subjects before they turned 15.
“By the time the kids were 15, we saw that, of the kids who we identified to have the anxious temperament, some of them were anxious and hyperactive, some of them were normal, but all of them had the hyperactive amygdala,” Fox said.
Of the group at risk for developing anxiety, Fox hopes to discover what environmental factors contribute to people developing or not developing the disorder.
For the next two years, Fox will be completing stress tests and functional MRIs on college-age students.