Soldiers who suffer more than one mild traumatic brain injury (TBI) face a significantly higher risk of suicide, according to a new study.
Researchers from the National Center for Veterans Studies at the University of Utah also found that the risk for suicidal behaviors and thoughts increased not only in the short term, but during the soldier’s entire life.
“Up to now, no one has been able to say if multiple TBIs, which are common among combat veterans, are associated with higher suicide risk or not,” said the study’s lead author, Craig J. Bryan, Ph.D., assistant professor of psychology at the University of Utah and associate director of the National Center for Veterans Studies.
“This study suggests they are, and it provides valuable information for professionals treating wounded combat servicemen and women to help manage the risk of suicide.”
During a six-month period in 2009, 161 patients who received a suspected brain injury while on duty in Iraq were referred to an outpatient TBI clinic at a combat support hospital.
The researchers found that one in five (21.7 percent) who had sustained more than one TBI reported suicidal ideation, described as thoughts about or preoccupation with suicide.
For those who had received one TBI, 6.9 percent reported having suicidal thoughts. Zero percent of those with no TBIs reported suicidal thoughts.
In evaluating the lifetime risk, researchers asked patients if they had ever experienced suicidal thoughts and behaviors up to the point they were assessed.
The increases were similar for suicidal thoughts during the previous year rather than at any time, according to the researchers. They found that 12 percent of those with multiple TBIs had entertained suicidal ideas during the past year, compared with 3.4 percent with one TBI, and 0 percent for no TBIs.
The researchers explained that they used suicidal ideation as the indicator of suicide risk because too few patients reported a history of making a suicide plan or had made a suicide attempt for statistically valid conclusions to be made.
Researchers also found that multiple TBIs were associated with a significant increase in other psychological symptoms, including depression and post-traumatic stress disorder (PTSD). However, only the increase in depression severity predicted an increased suicide risk, they noted.
“That head injury and resulting psychological effects increase the risk of suicide is not new,” Bryan said. “But knowing that repetitive TBIs may make patients even more vulnerable provides new insight for attending to military personnel over the long-term, particularly when they are experiencing added emotional distress in their lives.”
Because researchers were in Iraq, they were able to compile “a unique data set on active military personnel and head injury,” Bryan said. “We collected data on a large number of service members within two days of impact.”
He noted that researchers assessed only patients with mild or no TBI at the combat hospital. Those with moderate to severe TBI were immediately evacuated from Iraq.
The patients remaining in the study were divided into three groups based the total number of TBIs during their entire lives — zero, one, and two or more. The most recent TBI was typically within the days immediately preceding their evaluation and inclusion in the study.
Each soldier was also surveyed about their symptoms of depression, PTSD and concussions, and their suicidal thoughts and behaviors.
TBI is considered a “signature injury” of the Iraq and Afghanistan conflicts, according to the researchers. They note it is of particular concern because of the frequency of concussive injuries from explosions and other combat-related incidents. Estimated prevalence of TBI for those deployed in these two countries ranges from 8 percent to 20 percent, according to a 2008 study.
Additionally, past studies have found that suicide is the second-leading cause of death among U.S. military personnel, with the rate rising steadily since the conflicts began in Iraq and Afghanistan.
Prevalence of PTSD, depression and substance abuse have risen as well, especially among those in combat, and each has been shown to increase risk for suicidal behaviors, researchers noted.
“Being aware of the number of a patient’s head injuries and the interrelation with depression and other psychological symptoms may help us better understand, and thus moderate, the risk of suicide over time,” Bryan said. “Ultimately, we would like to know why people do not kill themselves. Despite facing similar issues and circumstances, some people recover. Understanding that is the real goal.”
The study was published in JAMA Psychiatry.
Source: University of Utah