Veterans with amygdala damage have lower risk of developing PTSD
If you or someone you love has PTSD, a new study may provide some hope for future treatments. In a study of veterans with penetrating traumatic brain injury (TBI), researchers found that those with damage to areas connected to the amygdala had decreased chances of developing post-traumatic stress disorder (PTSD).
The Research
A team of researchers at Brigham and Women’s Hospital analyzed 193 patients from the Vietnam Head Injury Study who had penetrating TBI to see if the location of shrapnel damage influenced their risk of developing PTSD.
Although previous studies have shown that people with damage to the amygdala—which is deep within the brain—are less likely to get PTSD, the team wanted to confirm those findings and determine a potential nonsurgical therapeutic target for the disease.
Previously, researchers had successfully treated addiction and depression using transcranial magnetic stimulation (TMS), although using the same circuit for PTSD had failed in trials. For this study, the team hoped to identify targets to do something similar for PTSD.
Over the course of this recent study, the team found that those with damage connected to the amygdala—often referred to as “the fear center of the brain”—were less likely to develop the mental health condition.
“Rather than continue with a trial-and-error approach of testing different targets, we turned to brain lesions to map out the circuit,” explained Director of the Center for Brain Circuit Therapeutics Dr. Michael Fox, who co-authored the paper for the journal Nature Neuroscience. “Some of these veterans who go shrapnel in their head went on to develop PTSD, but many of them did not.”
The researchers were able to map the exact location of damage in each patient and identify the neurological effects. By comparing the data of veterans who had no brain damage (some with PTSD and some who didn’t have PTSD), they found that connectivity within the circuit correlated with PTSD.
Trying TMS treatments
The researchers examined the previous trials using TMS to treat PTSD and found that, in cases where stimulation was hitting the intended circuit, the outcomes for patients were good.
In fact, during the study, one patient with PTSD actually requested TMS. The team planned a treatment and using the circuit found in the study, they improved his symptoms.
Although the patient’s results were good, the researchers will have to conduct a randomized controlled trial targeting the circuit to get approval from the FDA.
Limitations of the study
There were two major limitations of the study:
- The treatment results could change if the person was in a state of PTSD-induced fear at the time of treatment. For this study, the veterans were relaxed.
- This study included only veterans. PTSD in non-veterans might map to a different circuit.
“This is a very real brain disease, and we can localize it to certain brain circuits,” explained Dr. Shan Siddiqi, a Harvard Medical School assistant professor of Psychiatry and psychiatrist in the Brigham’s Center for Brain Circuit Therapeutics, who served as one of the study authors. “Unfortunately, people sometimes assume PTSD has to do with how mentally strong or weak a person is, but it has nothing to do with moral character.”
MBJ
Wendy Burt-Thomas writes about the brain, mental health and parenting.
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