A new study finds that veterans who developed post-traumatic stress disorder (PTSD) after a mild traumatic brain injury (TBI) tend to have a larger amygdala — the part of the brain that helps regulate emotion — compared to veterans with mild TBIs who didn’t develop PTSD.
The findings were recently presented at the American Academy of Neurology’s Sports Concussion Conference in Jacksonville, FL.
“Many consider PTSD to be a psychological disorder, but our study found a key physical difference in the brains of military-trained individuals with brain injury and PTSD, specifically the size of the right amygdala,” said Joel Pieper, M.D., M.S., of University of California, San Diego.
“These findings have the potential to change the way we approach PTSD diagnosis and treatment.”
Together, the right and left sides of the amygdala help control emotion, memories, and behavior. Research has shown that the right amygdala controls fear and aversion to unpleasant stimuli.
For the study, researchers evaluated 89 current or former members of the military with mild traumatic brain injury. Using standard symptom scale ratings, 29 participants were identified with significant PTSD. The rest of the participants had mild traumatic brain injury without PTSD.
Using brain scans to measure the volume of various brain regions, the researchers found that subjects with mild traumatic brain injury and PTSD had 6 percent overall larger amygdala volumes, particularly on the right side, compared to those with mild traumatic brain injury only. No significant differences in age, education, or gender between the PTSD and control groups were found.
The study also shows only an association and does not prove PTSD causes structural changes in the amygdala.
“People who suffered a concussion and had PTSD demonstrated a larger amygdala size, so we wonder if amygdala size could be used to screen who is most at risk to develop PTSD symptoms after a mild traumatic brain injury,” said Pieper.
“On the other hand, if there are environmental or psychological cues that lead to brain changes and enlargement of the amygdala, then maybe such influences can be monitored and treated.”
“Further studies are needed to better define the relationship between amygdala size and PTSD in mild traumatic brain injury. Also, while these findings are significant, it remains to be seen whether similar results may be found in those with sports-related concussions,” said Pieper.
Pieper emphasizes that the current study focused on veterans with blast injuries, not those with sports-related concussions.
Source: American Academy of Neurology