Scientists Are Better Understanding the Link Between Traumatic Brain Injury and Suicide

The lifelong consequences of traumatic brain injury (TBI) can be severe, but until the last decade, they received little attention from doctors treating military veterans. According to the Department of Defense, more than 458,000 service members were diagnosed with a TBI from 2000 to 2022, though evolving diagnostic standards likely mean that the number is higher.

TBI is the result of serious or repeated hits to the head, at any level that causes brain damage. Though it’s a physical injury, the consequences of suffering this type of head trauma are most often mental and emotional. For veterans in particular, this burden can lead to behavior like substance abuse and self-harm. Research on excess death among veterans has identified a dangerous relationship between TBI and post-traumatic stress disorder, with suicidal ideation and behaviors appearing with notable frequency in those with both conditions. A new study further spells out the risks for veterans with brain injuries by taking all lifelong mental-health diagnoses into account, mapping for the first time on a large scale how brain injury can play an indirect role in suicide as well.

“We're really trying to address people's challenges from a very non-stigmatized, whole-human perspective,” says Lisa Brenner, director of the Department of Veterans Affairs-affiliated Rocky Mountain Mental Illness Research, Education and Clinical Center and the lead author of the study. To do so, Brenner and her team pulled health information on more than 850,000 U.S. Army soldiers who returned from deployment before the age of 25, over 100,000 of whom had at least one documented TBI in their health records and nearly 2,700 of whom ended their own lives at some point following deployment. Then, they traced mental health diagnoses over time, looking for patterns in the onsets and outcomes of conditions such as mood disorders, substance and alcohol use disorders, and anxiety.

Read More: This Is What It Is Like to Live With a Brain Injury

In line with previous studies, the new paper, published yesterday (July 31) in the journal JAMA Network Open, found that prior TBI increased the likelihood that soldiers would be diagnosed with any of the 14 mental health conditions included. Post-deployment diagnoses for all were higher in the brain injury group. After returning from service, for instance, substance abuse diagnoses increased 100% in the TBI group, compared to a 15% increase in soldiers without a TBI. Anxiety diagnoses also rose, with a 75% increase in those with TBI and a 62% increase in those without.

But for the researchers, the most remarkable finding comes from the timelines the team built for veterans who committed suicide. Overall, with all other factors accounted for, soldiers with a history of TBI who took their own lives did so 21% sooner than those without brain injuries after returning from deployment. When additional diagnoses were added in, this rate sped up even more. After being diagnosed with a substance-use disorder, soldiers with TBI committed suicide 63% sooner than those without. The difference in rate was similar for alcohol use disorders, PTSD, mood disorders, and any combination of two post-brain injury diagnoses. “We weren’t surprised,” says Brenner, “but it’s sobering.”

It’s stark evidence that TBI not only increases the likelihood of future mental health disorders, but also makes them worse when they do occur. It’s a vicious feedback cycle, says Brenner, particularly when people face an “accumulation of these health events over their lifetime.” 

Though treating these compounding disorders simultaneously in service members is just as important as in the general public, says Brenner, some specific findings in the study—particularly the distinct danger of brain injury combined with substance use disorders—are likely reflective of a very specific cohort during a very specific period of time. The study data comes mostly from veterans who fought in Iran and Afghanistan and returned in the ‘00s, says Brenner, and “people came out with lots of pain-related symptoms like musculoskeletal pain and headache pain.” Doctors at the time were willing to prescribe opioids, particularly for those with brain injury, which can be associated with chronic pain even in civilians. 

Treatment for veterans today is a lot closer to Brenner’s holistic vision, but there are still leaps and bounds to be made. A five-year study on TBI in veterans, funded by the Department of Defense and the Department of Veterans Affairs, is expected to wrap up next year, and will be the largest of its kind. Brenner’s hope is that it will offer more good reasons to treat multiple diagnoses in a person as one mental health burden—the way people actually experience these conditions. “In the early days, when folks were coming back from Iraq and Afghanistan, we spent a lot of time and energy trying to figure out, 'is this TBI is this PTSD? Is this both?'” Brenner recalls. “The veterans, they weren't thinking about themselves like that.”

If you or someone you know may be experiencing a mental-health crisis or contemplating suicide, call or text 988. In emergencies, call 911, or seek care from a local hospital or mental health provider.