People who have sustained multiple brain injuries throughout their life were more likely to report suicidal thoughts than people with one or no concussions, according to a new study of deployed U.S. military personnel.
"Personnel who had sustained more than one concussion in their lives were significantly more likely to be suicidal in their past—as well as in the past year," said Craig Bryan, the study's lead author from the University of Utah National Center for Veterans' Studies in Salt Lake City.
Suicide is currently the second leading cause of death among military members, and claimed about 16 lives per 100,000 members in 2008. That's about a 50 percent increase since 2001, according to a 2011 report from the RAND Corporation.
While the new results are limited to military personnel in a combat zone, the findings may also have implications for other people at an increased risk of concussion.
Bryan and his colleagues write in JAMA Psychiatry that the increase in suicide is partially driven by a rise in psychiatric illnesses among military personnel, who may have been exposed to combat operations in Iraq and Afghanistan.
Traumatic brain injury, one of the signature wounds of the two wars, has also been linked to an increased risk of suicide. But the researchers write that few studies have looked at the effects of multiple brain injuries on suicide risk.
For the new study, the researchers used information on 157 military personnel and four civilian contractors who were sent to a combat support hospital in Iraq during 2009 for suspected brain injuries. On questionnaires, 18 said they had never been diagnosed with a concussion before, 58 said they'd been diagnosed with a brain injury once, and 85 reported multiple diagnoses. Most were mild injuries, Bryan said.
Also, 18 patients reported previous suicidal thoughts, two said they had planned a suicide, and two said they attempted it. Overall, the researchers didn't find evidence of suicidal thoughts among any of the patients who hadn't reported previous concussions.
About seven percent of people with one diagnosed brain injury reported previous suicidal thoughts—about three percent in the past year. And about 22 percent of patients with multiple previous concussions reported suicidal thoughts in the past—12 percent in the past year.
What's more, the researchers found the more concussions a service member had sustained, the stronger the association between depression and suicidal thoughts. "In those individuals who had been repeatedly concussed, it's almost like they're more sensitized.... It becomes easier for that individual to experience depression and suicidal (thoughts) as a result," Bryan said.
BATTLEFIELD TO PLAYING FIELD
While the new results are limited to military personnel in a combat zone, Bryan suggested the findings may also have implications for other people at an increased risk of concussion, such as football players. "What we learn in the military may help inform what we know about injuries in the athletes as well," he said.
Concussions in football have been thrust into the spotlight after reports of players suffering from depression or memory trouble long after retiring. Last year, former San Diego Chargers star Junior Seau committed suicide after what some believe were years of concussion-related depression.
Bryan cautioned, however, the research can't prove concussions caused the suicidal thoughts. Furthermore, he said their research shows the majority of people with multiple brain injuries don't report such thoughts.
"Even if you do experience suicidal thoughts, it doesn't necessarily mean you're going to make a suicide attempt," said Bryan, because there are treatments available.