Unthinkable_ Who Survives When Disaster Strikes - and Why - Amanda Ripley [58]
The tech administering the MRI asked Jerry some basic questions to make sure he was doing OK. The test showed that he had some shrapnel behind his ear that he hadn’t known about. The tech asked Jerry if he felt a burning sensation. When Jerry didn’t answer, the tech figured he had fallen asleep in the machine. But really he was just lying there silently crying in the dark.
Jerry has now participated in five different studies on posttraumatic stress disorder. “I guess they like us a lot. We’re sort of talkative type guys. Plus, we always bring jerky for everyone.” He hates flying, as does his brother, and being in a big city is intensely stressful for him. But he goes through the ordeal because he wants doctors to learn more about the illness so they can help soldiers coming home from Iraq. “This is far worse than Vietnam. These guys are going to have severe problems. So I need to help.”
Almost a third of Vietnam vets suffered from posttraumatic stress disorder after the war, according to the 1988 National Vietnam Veterans Readjustment Study. That’s a lot of people. It would make sense to conclude that these men had simply experienced more horrendous trauma than the others. They were only scarred because of what had happened to them, not because of who they were.
But Gilbertson found something different. When he looked at the images, he saw that, within the twin sets, the hippocampi were about the same size. The trauma of war had not significantly altered the size of the hippocampus in the brothers who had gone to Vietnam. But there were significant differences between sets of twins. The twin sets that included vets with posttraumatic stress disorder had smaller hippocampi than the twin sets that included veterans without the disorder. In other words, a smaller hippocampus seemed to predate the trauma. Certain people were at higher risk of developing posttraumatic stress disorder before they even left for Vietnam. We can deduce, then, that certain people will likely have a harder time processing fear in a disaster—and recovering from that trauma later.
Jerry, for one, is not too surprised by the results. He knows that Vietnam damaged him. “I loved people. Damn, I was very popular in high school. It just changed after I got home.” But he also says his problems predated the war. Depression runs in his family, he says. His senior year of high school, his girlfriend broke up with him, and he remembers telling her he was going to go to Vietnam to get killed. “Mentally, I was depressed even before Vietnam. Personally, I think that’s why it messed me up so much.”
The hippocampus is just one factor in the sprawling equation for posttraumatic stress disorder. Other things matter too, Gilbertson stresses. The amount of trauma, the degree of family support for the victim—all of these things can massively compound or contain the damage. Suffering accumulates, like debt.
Plus, having a smaller hippocampus isn’t necessarily a negative in every situation. Gilbertson suspects that a smaller hippocampus might actually help some people in a life-or-death situation—by making them hypervigilant, for example, and less prone to waste time in denial. It’s easy to imagine how a smaller hippocampus might have been an evolutionary advantage in some situations, and a handicap in others. So he doesn’t think we should screen people with MRIs before they join the military or the police. The brain is too complicated to be reduced to the size of one of its parts.
My Naked Brain
We all wonder how we would react in a disaster. As I learned more about specific traits that may predict resilience, I couldn’t help wondering about my own profile. I don’t think I dissociate more often than average, but I don’t always find meaningful purpose in life’s turmoil either. Sometimes I just find turmoil. I can be