Doctors and scientists have believed a link exists between post-traumatic stress disorder (PTSD) and traumatic brain injury (TBI) since the two conditions became the signature injuries of veterans returning from the wars in Iraq and Afghanistan. Now, research is confirming those beliefs with findings that suggest concussive bomb blasts may make brains more vulnerable to the later development of PTSD.
One such study recently published in the journal JAMA Psychiatry examined soldiers who had been deployed to Iraq and Afghanistan. According to the results, soldiers who experienced a concussion or mild TBI were twice as likely to develop PTSD compared to their fellow soldiers.
PTSD is characterized by a variety of psychological issues, such as insomnia, chronic depression, eating disorders, anger or behavior problems, and substance abuse. Estimates from the VA suggest between 11 and 30% of veterans from the different military branches experience the disorder following their time in the service.
For the study, researchers led by Dewleen Baker, a psychiatrist from UCSD and the VA San Diego Healthcare System, evaluated over 1,600 Marine and Navy service members from San Diego’s Camp Pendelton. The soldiers were assessed before and after their deployment, as NPR reports.
“At one point we got this battalion that went to Helmand Province in Afghanistan and literally 50 percent of them were complaining of blast exposures and symptoms,” Baker said, according to NPR. “I got concerned.”
The results ultimately showed that troops who experienced TBI during their service were twice as likely to develop post-traumatic stress disorder as well.
Another recent study from the University of California, Los Angeles, helps strengthen this link. In the study, healthy lab rats were compared with rats who had experienced a TBI. After being evaluated, the rats were exposed to fear conditioning before being examined again. The team found that the injured rats showed changes to cells in the brain’s amygdala, which is essential for transmitting sensory information and responding to fear.
The results suggest traumatic brain injuries may make changes to the brain that could amplify an injured individual’s response to frightening stimuli or experiences.
“And we think that that’s the way TBI has of increasing your susceptibility to post-traumatic stress,” Fanselow Michael, a psychology professor at UCLA and an author of the UCLA rat study, told NPR.