NOT LONG AGO, MOST THERAPISTS WHO HEARD A STORY like Albert Grow's would have thought about what his experience in Vietnam did to his relationship with his family, his community and his sense of self. Few would have given much thought to what it did to his biochemistry. That is about to change.

Grow, a policeman in Salem, New Hampshire, came back from Vietnam nearly 30 years ago on a "freezer flight" a transport plane piled with body bags. At the Boston airport, a woman called him trash and spit in his face. Not long afterward, he punched out two coworkers in a photo lab because they wore black arm bands to honor the Vietnamese dead. After a brief stay on a psychiatric ward, he burned his Marine uniform in his parents' backyard. He avoided war movies. He didn't go to his sister's wedding.

Grow moved to New Hampshire and for decades lived an ordinary life: he finished college, became a husband and a father and coached Little League. Then, during the Gulf War, he watched American missiles explode on television and thought about his 14-year-old son. "I remember saying, You're not going to do it to him. Not him," he says. "It was like somebody took the switch I had turned off and turned it back on."

He began to see the faces of dead young men he had long succeeded in forgetting. He would drive fast for miles, going nowhere, or rent a motel room and sit in the dark for days to keep his anger away from his wife and son. He was put on anti-depressants and…