When it comes to post-traumatic stress disorder (PTSD), much of the clinical research focuses on improving the condition rather than predicting it. However, a new study carried out at Tufts University has just uncovered a brain marker that seems to show who is more likely to develop PTSD when exposed to trauma. It all has to do with how one region of the brain is activated by perceived threats.
One of the trickier aspects of understanding PTSD is figuring out why some people fall prey to the condition and others don't – even if they've experienced similar traumas. In pursuit of the answer, the Tufts researchers decided to focus on one aspect of the condition known as hypervigilance, or "always always feeling that you need to monitor your environment for potential threats," according to Cecilia Hinojosa, the study's first author.
In designing the study, Hinojosa and her team decided to focus on identical male twins, which helped control for biological variability. In the test group, they looked at twins in which one brother had experienced trauma and developed PTSD, while the other had not experienced trauma. In the control group, they looked at brothers in which one had experienced trauma and not developed PTSD, and the other had not experienced trauma at all.
The study participants were placed into functional MRI (fMRI) machines, which map brain activity as individuals are subjected to various stimuli. In this case, the twins were all shown images of a surprised face and a neutral face.
In the case of the individuals who had developed PTSD in response to trauma, the researchers found heightened activity in the brain's amygdala, a region that plays a role in our fear response – particularly our flight, fight, or freeze response.
The same regions were activated in the twins of the PTSD participants who had not experienced trauma. Conversely, the amygdala did not show heightened activity in the brains of the control group where no PTSD was present. This led the researchers to conclude that there is a definite link between activation in this brain region and the propensity to develop PTSD.
In addition to seeing the activity in the amygdala in the test group, the researchers also found that there was reduced activity in a region of the brain known as the medial frontal gyrus, which helps tone down the amygdala's response when presented with situations that are actually not threatening. They only saw this activity in the brothers with PTSD – not their twins – which led them to posit that this particular brain pattern was a result, and not a cause, of the condition.
The researchers hope that the finding could help either steer those prone to PTSD away from roles that might trigger the condition or "we could potentially provide them with treatments as soon as they experience that trauma to hopefully prevent the development of PTSD symptoms," Hinojosa says. That goal is similar to that of researchers at Indiana University School of Medicine, who reported in 2019 that a blood test could potentially identify those most likely to develop PTSD.
Hinjosa and her team say that a next step to their work would be to increase the sample size and introduce women into the test group.
The research has been published in the Journal of Psychiatric Research.
Source: Tufts University