Shredded connections deep in the brain. Battered and scarred blood vessels that are no longer able to support neurons. Clumps of dead cell debris marking a long pattern of injury.
The results of the autopsy of Robert M. Card II, the Army Reservist who killed 18 people, then himself, in the deadliest shooting in Maine’s history, left little question that his brain was profoundly damaged. But the finding raises other questions that have broad implications for the military and for the nation’s millions of veterans.
Mr. Card was a grenade range instructor who never deployed to combat. He is not known to have ever hit his head in a serious car crash, he never played football, and he does not appear to have had any other accidents that might account for the damage to his brain.
His only exposure came from routine training blasts on the training range — at a level that is supposed to be safe.
If those blasts were still strong enough to profoundly damage his brain, as it appears happened, then how many other troops are being exposed to the same risk? How many veterans may be struggling with similar injuries that have gone unseen or been misunderstood? How should those veterans be treated if they seek mental health care, or are accused of crimes?
“The implications are just so large,” said Frank Larkin, a former Navy SEAL and sergeant-at-arms of the U.S. Senate, whose son, Ryan, also a Navy SEAL, died by suicide and was found to have extensive brain damage from blasts.
“A lot of the problems, the military thought they were from war,” Mr. Larkin said about veterans who face mental health struggles. “We now have to acknowledge that the weapons and the training are creating a major problem.”
Mr. Card’s brain shows that the Pentagon’s current safety guidelines for blast exposure are likely to be inadequate, Mr. Larkin said.
The strength of blast exposure is often measured in pounds per square inch of the pressure wave. The military says that anything below 4 p.s.i. is safe for the brain. Grenade-range exposure for troops in training typically measures around 1 p.s.i., according to Army studies.
The damage in Mr. Card’s brain suggests that 1 p.s.i. may be enough to cause profound injuries, especially after hundreds of exposures.
“That means we may have to rethink how we design weapons, and rethink how we train,” Mr. Larkin said. “The military has to be able to do its mission, but they can get a lot smarter about preventing as much exposure as possible.”
The Army said in a statement that the laboratory findings about Mr. Card’s brain “underscore the Army’s need to do all it can to protect soldiers against blast-induced injury.”
The guidelines on blast exposure are being updated, the statement said, adding that the Army will soon begin a service-wide safety campaign to increase understanding of potential risks.
In the meantime, though, large numbers of troops continue to train every day with weapons that create potentially harmful blasts.
To be clear, Mr. Card is an outlier in more ways than one. Hundreds of thousands of veterans have been diagnosed with traumatic brain injuries since 2001, but very few of them have committed murder. And there is no way to know with any certainty what had caused those few to kill or whether their mental problems stemmed only from the brain injuries.
Even so, it is well documented that veterans who were exposed to blasts in the service often struggle to sleep and have trouble with depression, anxiety, substance abuse and regulating their moods. They often lose jobs and miss promotions, see marriages fall apart and experience other problems that rarely get attention beyond the kitchen table.
Two soldiers who served with Mr. Card in the grenade pits said in interviews they were struggling now with mental health issues, and have not slept well in years. A third has struggled with alcohol, was hospitalized in the fall for mental health issues according to other soldiers and told a local news station that he was facing charges in Maine for domestic violence.
Many veterans who have been exposed to blasts are diagnosed with post-traumatic stress disorder, and the underlying brain injury is often missed, according to Dr. Lee Goldstein, a neurologist and psychologist at Boston University who did part of the analysis of Mr. Card’s brain.
“We know that so many people go to war and come back different,” Dr. Goldstein said. “This brain tells us that a good deal of that could have nothing to do with war at all.”
The damage seen in Mr. Card’s brain should prompt the military and the Department of Veterans Affairs to rethink their approach to the treatment of P.T.S.D., he said.
The connections between his brain’s frontal lobes, which are responsible for executive function, and the parts of the brain that generate fear, anger, impulsiveness and violence were badly frayed.
“If your frontal lobes are not online, you are not acting like a normal adult who can exercise judgment and tamp down aggression,” Dr. Goldstein said.
That is a major problem, because one of the most widely used therapies for P.T.S.D., called prolonged exposure therapy, relies on revisiting trauma to try to train the frontal lobes to control fear and anxiety.
“If you don’t have fully functioning frontal lobes, that ain’t happening, and people won’t get any benefit,” Dr. Goldstein said.
Large numbers of veterans who are treated for P.T.S.D. report little benefit from exposure therapy, or even a worsening of symptoms, and drop out. In some of those cases, at least, that may be a hint that brain injury may figure in their symptoms.
Studies show that service members who work in military jobs that expose them to blasts experience more behavioral health problems and drug and alcohol abuse than their peers in other jobs. They have high rates of divorce, and their suicide rates are far higher than others in the military.
Among artillery crews that fired a large number of rounds during combat deployments, The New York Times found that some troops experienced paranoia and delusions.
Once out of the military, blast-exposed veterans are more likely than others to commit crimes, according to Brock Hunter, a lawyer in Minneapolis who specializes in representing veterans accused of crimes. Mr. Hunter founded the Veterans Defense Project, a nonprofit that seeks to work with courts to steer veterans into treatment rather than jail.
He recently represented a Marine veteran who had been exposed to hundreds of artillery blasts and who killed his neighbor.
During the wars in Iraq and Afghanistan, Mr. Hunter said, courts across the country began to recognize that many veterans returned from deployment struggling with traumatic brain injuries and P.T.S.D., and communities began to create veterans’ treatment courts that offer deferred sentences to veterans who complete treatment.
“But I don’t think any of us understood the idea that cumulative blast could be so damaging,” Mr. Hunter he said. “This is a wake-up call that you don’t need to deploy to be seriously impacted by military service.”
He said he had learned over the years to make a habit of asking his clients about exposure to roadside bombs and traumatic experiences, but it had never occurred to him to ask about blasts in training. He now plans to ask the question of every client.
Whether courts and prosecutors will be open to treating blast-exposed veterans with the same sympathy and support they extend to veterans with P.T.S.D. is an open question, Mr. Hunter said. But Mr. Card’s brain offers a clear example of the potential damage veterans can suffer, even if they never deploy.
“This is new, and I think it will take time for people to understand the injury,” he said. “It took years for lawyers and courts to learn to understand P.T.S.D. I suspect it will take years for this as well.”
