“Fear is the enemy,” says Comdr. Eric Potterat, PhD, a Navy Special Warfare group psychologist. The mental stress of war has claimed more casualties in Iraq and Afghanistan than bombs and bullets. “Psychological trauma can have profound negative effects on brain function,” says James B. Lohr, MD, who spent 12 years as chief of psychiatry at the Veterans Affairs Healthcare System in San Diego.
Fear should be our best friend. It’s a chemical reaction, a signal to pay attention to a threat. It’s our brain alerting us to danger, triggering the classic fight-or-flight response—sweaty palms, dry mouth, an increase in breathing and heart rate, a jolt of adrenalin—to help us survive. But when the brain doesn’t return to normal after a stressful incident, or when there are too many incidents, this hormone-driven alert system can turn toxic. The nature of our post-9/11 conflicts—enemy combatants embedded among civilian populations, using unconventional tactics and weapons like IEDs—has been especially hard on soldiers, says Lester: “They are in combat more frequently, with an enemy that uses terror as a weapon.” To Lester, recent military practice—like troops serving multiple combat tours with little time in between to recover—is practically a formula for creating PTSD.
The Inner Warrior
To understand what goes wrong in the brains of combat veterans who develop PTSD, and to try to prevent it from happening to others, neurobiologist Lilianne Mujica-Parodi, PhD, has spent years tossing volunteers with sensors all over their bodies out of airplanes. Her Navy-funded research measures physical fear responses, comparing sheer fright factors to the results of mental-processing tests she administers before, during, and after the skydiving flight.
Mujica-Parodi has discovered that in most cases, the brain does some predictable things when a human jumps out of a perfectly good airplane. Stress hormones flood the fear-response system, and thoughts narrowly focus on one thing: getting out of the air and onto the ground.
There are, however, the unflappable few subjects who don’t experience this wild swing of mental and physical reactions. They demonstrate some of their clearest thinking in the middle of a plunge, and when it’s over, their fear-response systems quickly return to normal.
“You don’t want someone without a fear response at all,” Mujica-Parodi says. “That’s not brave; that’s just abnormal. But a high stress response is also unhealthy.” The optimal fear response, she says, accurately assesses risk, saves room for cognitive thought, and rapidly returns to baseline when the danger passes. Brains that can do this are a gift of DNA, according to Mujica-Parodi, what she calls warrior brains. The soldiers who possess them benefit from an ideal balance of neurological and biological responses.
Using brain scans, Mujica-Parodi has seen how the fear-response system “cools down” faster in warrior brains than it does in the brains of more vulnerable subjects.
While her research is still experimental, Mujica-Parodi maintains that it’s now possible to identify someone with either a warrior brain or a vulnerability to stress disorders with the same certainty that we can diagnose an increased risk for diabetes. She envisions a day in the future when a brain scan will be part of military training, though there are no plans in any branch for such screening, which would surely raise a host of ethical issues. “You wouldn’t accept someone in Special Forces if he had weak legs,” she says. “Soon we’ll be able to screen people for emotional weaknesses. A person with an incapacitating fear response is a danger to himself, his team, and the mission.”