three teen girls sitting against a wallActivation of the amygdala, part of the brain that affects emotional reactions and decision-making, can indicate which individuals are at-risk for developing the symptoms of post-traumatic stress disorder (PTSD) after a traumatic experience finds research from a collaboration between the University of Washington, Boston Children’s Hospital, Harvard Medical School, and Boston University. The researchers compared brain scans of adolescents taken shortly before the Boston Marathon bombings with questionnaire responses from after the attack. The teenagers whose amygdalae reacted more strongly to negative emotions were also those most affected by the attack.

The researchers performed functional magnetic resonance imaging (fMRI) brain scans on Boston-area teenagers in the year before the Boston Marathon attack. In this original study, the teens viewed neutral images, like a button or chair, and negative images, like people fighting, while researchers observed the blood flow to the amygdala and hippocampus. The teens rated their emotional response to the images.

One month after the Boston Marathon attack, the researchers sent online surveys to the teens who participated in the brain scan study. The survey assessed PTSD symptoms like trouble concentrating or recurring thoughts about the attack. The survey asked about the teens’ experiences related to the attack, including whether they had been at the race, how much social media they consumed, if they had been on lockdown at home or school, and how their parents responded. The researchers compared the fMRI data from before the attack to the survey responses.

Increased reactivity in the amygdala to negative emotional stimuli was significantly associated with later developing symptoms of PTSD. The teens who had heightened activity to the negative images during the first study were more likely to experience PTSD symptoms after the Boston Marathon attack.

“The amygdala responds to both negative and positive stimuli, but it’s particularly attuned to identifying potential threats in the environment. In the current study of adolescents the more their amygdala responded to negative images, the more likely they were to have symptoms of PTSD following the terrorist attacks,” explained Katie McLaughlin of Boston Children’s Hospital and Harvard Medical School, the study’s first author.

The study may help in identifying individuals most at-risk for PTSD and could support the development of PTSD treatments.

This research is published in the journal Depression and Anxiety.

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