David Metcalf’s last act in life was an attempt to send a message — that years as a Navy SEAL had left his brain so damaged that he could barely recognise himself.

He died by suicide in his garage in North Carolina in 2019, after nearly 20 years in the Navy. But just before he died, he arranged a stack of books about brain injury by his side, and taped a note to the door that read, in part, “Gaps in memory, failing recognition, mood swings, headaches, impulsiveness, fatigue, anxiety, and paranoia were not who I was, but have become who I am. Each is worsening.”

Then he shot himself in the heart, preserving his brain to be analysed by a state-of-the-art defence department laboratory in Maryland.

The lab found an unusual pattern of damage seen only in people exposed repeatedly to blast waves.

The vast majority of blast exposure for Navy SEALs comes from firing their own weapons, not from enemy action. The damage pattern suggested that years of training intended to make SEALs exceptional was leaving some barely able to function.

But the message Lieutenant Metcalf sent never got through to the Navy. No one at the lab told the SEAL leadership what the analysis had found, and the leadership never asked.

It was not the first time, or the last. At least a dozen Navy SEALs have died by suicide in the last 10 years, either while in the military or shortly after leaving. A grass-roots effort by grieving families delivered eight of their brains to the lab, an investigation by The New York Times has found. And after careful analysis, researchers discovered blast damage in every single one.

It is a stunning pattern with important implications for how SEALs train and fight. But privacy guidelines at the lab and poor communication in the military bureaucracy kept the test results hidden. Five years after Lieutenant Metcalf’s death, Navy leaders still did not know.

Until The Times told the Navy of the lab’s findings about the SEALs who died by suicide, the Navy had not been informed, the service confirmed in a statement.

A Navy officer close to the SEAL leadership expressed audible shock, and then frustration, when told about the findings by The Times. “That’s the problem,” said the officer, who asked not to be named in order to discuss a sensitive topic. “We are trying to understand this issue, but so often the information never reaches us.”

The lack of communication has led Navy leaders to overlook a potentially critical threat to its elite special operators. When the commander of SEAL Team 1 died by suicide in 2022, SEAL leaders responded by ceasing nearly all operations for a day so the force could learn about suicide prevention. According to four people with knowledge of the commander’s case, his brain was later found to have extensive blast damage, but because the leaders were not told, they never discussed the threat of blast exposure with the force.

A growing number of scientists suggest that troops are getting brain injuries from firing heavy weapons. An old party trick involving a beer bottle explains the physics of what happens when a blast wave hits the brain, and the damage it can cause.
Evidence suggests that the damage may be just as widespread in SEALs who are still alive. A Harvard study, published this spring, scanned the brains of 30 career Special Operators and found altered brain structure and compromised brain function in nearly all of them. The more blast exposure the men had experienced, the more problems they reported with health and quality of life.

That study was funded by Special Operations Command, which has been at the forefront in the military’s effort to understand the issue. In December, the study’s main author briefed the command’s top leaders, including from the Navy SEALs.

“We have a moral obligation to protect the cognitive health and combat effectiveness of our teammates,” Rear Adm. Keith Davids, the commander of Navy Special Warfare, which includes the SEALs, said in a statement. He said the Navy is trying to limit brain injuries “by limiting blast exposure, and is actively participating in medical research designed to enhance understanding in this critical field.”

But without the data on suicides, a key piece of the problem was never discussed at the briefing.

Blows to the head

The communication breakdown is part of a broader disconnect in the defence department, which spends nearly $1 billion each year on brain injury research, and many billions more to train and equip troops, but does comparatively little to ensure that the latest science on brain injury informs practices in the ranks.

Lieutenant Metcalf’s wife, Jamie Metcalf, said in an interview that she had come to see his death as an effort to draw attention to a widespread problem.

“He left an intentional message, because he knew things had to change,” she said. When told the information about his brain had not reached the SEAL leadership, she sighed and said, “You’re kidding me.”

The military readily acknowledges that traumatic brain injury is the most common injury from recent conflicts. But it is struggling to understand how many of those injuries are inflicted by the shock waves unleashed by troops’ own triggers.

There are signs that the damage can come from a wide array of weapons. Artillery crew members who fired thousands of rounds in combat came home plagued by hallucinations and psychosis. Mortar teams suffered from headaches and deteriorating memory. Reliable soldiers suddenly turned violent and murdered neighbours after years of working around the blasts from tanks and grenades in combat or in training.

Blast waves may kill brain cells without causing any immediately noticeable symptoms, according to Dr. Daniel Daneshvar, chief of brain injury rehabilitation at Harvard Medical School.

“People may be getting injured without even realising it,” Dr. Daneshvar said. “But over time, it can add up.”

People’s brains can often compensate until injuries accumulate to a critical level, he said; then, “people kind of fall off a cliff.”

New York Times News Service