When it comes to treatment, however, there isn’t a consensus on how, or whether, to integrate the concept of growth. Patricia Watson, a senior education specialist for the National Center for P.T.S.D., says studies indicate that pushing people toward growth can be ineffective, making patients believe that they need to be strong even when they are in mental agony. Rachel Yehuda, director of the Traumatic Stress Studies Division at Mount Sinai School of Medicine, says that timing is crucial. Bringing up the idea of growth before patients have completed therapy — which often involves what is called “prolonged exposure,” or talking through the trauma in detail again and again to help patients overcome their fear of the event — might not be “a therapeutic thing to say to someone who is suffering,” she says. “I don’t reject the idea; I just want to be careful to do it right.”

Many of the V.A. psychologists I spoke with were familiar with the idea of post-traumatic growth — some have even done research on the subject — yet not all of them have used it in therapy, and the V.A. has no official policy on it. Social workers at Fort Sill, however, introduce the idea of growth right away, though as a long-term objective. When soldiers come in shattered by a traumatic experience, social workers explain that they will lose sleep, be angry, upset and depressed, and that these are normal reactions. But they also tell them that there is a chance that, given time, they may be stronger as a result of what they went through.

Some academics question whether post-traumatic growth is a real phenomenon, or at least one that can be objectively defined. Nearly all studies ask people to look back and recount how an event changed them. In the wake of trauma, people might tell themselves that they changed for the better, if only as a way of making some sense of a senseless tragedy. As far as friends and spouses are concerned, however, the person might have not changed at all. “I have no doubt that there are people, perhaps many people, who do change in positive ways, but we are not able to measure it,” says Howard Tennen, a professor of community medicine and health care at the University of Connecticut. And if you can’t measure it, Tennen says, then you really have no business trying to promote it.

Tedeschi would love to see better studies. But he also is adamant that the phenomenon is real and can be measured, even if researchers must rely on self-reported, after-the-fact accounts. “Virtually all psychological research relies on memory,” he told me. “If you decide that memory is unreliable, then you have to throw out everything that has ever been published in psychology.”

Tedeschi told me about one of his patients whose helicopter was shot down in Vietnam. As he fell from the sky in the midst of gunfire and explosions, a peace came over him. He saw the jungle around him, and it was beautiful. He felt connected to everyone, even enemy soldiers. Since then he has reflected on the experience, delving into philosophy and religion. He has reached out to others by volunteering his time. He has tried to remain true to that connection he felt long ago. “Maybe that was all an illusion,” Tedeschi says. “But that became a guideline for his life, so I don’t think you can dismiss it. People can have profound personal experiences that directly change their perception and philosophy. That may show up in the things they do, but it also may not.”

For most people, change does not occur in a transcendent moment but over years of prosaic searching. That was the case for Sergeant Beltran, whose Humvee was blown apart by the I.E.D. in Iraq. Rebuilding his life was a struggle, but over time he became a trainer in the Comprehensive Soldier Fitness program at Fort Sill and now is working at Fort Stewart, in Georgia, where he and his new wife, Ronda Jones-Beltran, have bought a house. “Instead of labeling myself as a P.T.S.D. veteran, I say that I am a post-traumatic-growth veteran,” he told me. “I am a person looking forward.”