WELCOME, SILENCE My Triumph Over Schizophrenia By Carol S. North, MD Simon and Schuster. 316 pp. $17.95

A schizophrenic who recovers, the saying goes, probably wasn't schizophrenic to begin with. Facing a nearly incurable disease of uncertain cause, Carol North did recover, to the extent that she was able to complete medical school and become a practicing physician. In this exhilarating, at times harrowing, memoir, North traces her remarkable battle.

"Six years old and afraid of everything ..." she writes. "It wasn't easy dodging killer birds and escaping murderers and kidnappers every day." Nights she was tormented by erratic voices, fires, ghosts, bugs. She was a bright child, and when the family doctor and her well-meaning parents instructed her to stop being so afraid of everything, North developed elaborate systems for camouflaging her fears. Believing her mother could read her thoughts, for instance, North began to think in code, intentionally scrambling her thoughts as they came to her. As a result, she became confused at times and had to write down what she really thought in another code. Overwhelmed by visual disturbances on her way to school -- low-flying helicopters -- she devised a new route so she wouldn't be late. All during this time, even as her symptoms worsened, she earned high grades.

Her account is forthright and unsentimental, but the picture that emerges of a young woman trying to conceal her illness even from her own family is unforgettable. After being hospitalized for the first time, North begged the physician not to tell her parents: "This would come as a shock to them. Things like this just didn't happen in our family." She draws a clear picture of her psychotic states, so the reader experiences her illness from within and without. The first time she was hospitalized: "Snap, a man in white snapping rubber fingers right in front of my face, twelve colors radiating off them like sunrise in the Grand Canyon ... Damn it, stop that ... I am torn by terror into billion dimension-spaces and you are doing a cosmic watercolor ..."

As Carol North's condition worsened from occasional breakdowns to increasingly severe and frequent delusions that involved a cacophony of conniving voices urging her to do herself in, she was hospitalized more frequently. She lived in terror not only of her illness but of the treatments: the debilitating side effects of the medications made it almost impossible for her to concentrate on schoolwork. Then North experienced an episode so severe she was forced to drop out of medical school. She lived for medical school and her goal of helping others, and she thought, "If I couldn't pursue my dream of medical school, then I didn't care to live."

Her physician was desperate and, with North's approval, decided to try a new experimental treatment -- dialysis. The object was to filter her blood through a kidney dialysis machine on the theory that it would remove certain toxic elements that were causing her illness. Following the second treatment, the miraculous occurred. When her doctor called her, she listened in awe. "His voice flowing out of the receiver sounded unusually clear, like the chop of a hatchet in the woods after a heavy snowfall ... Clarity such as I'd never heard before."

Her case was one in a million, and why this particular treatment succeeded for North but not for others is unknown. Schizophrenia is believed to be caused by a variety of factors, hereditary and biochemical, and in North's case, the cause was evidently an agent that could be filtered from her blood.

The significance of Carol North's experience, however, transcends her cure and lies in the triumph of human will. Confronted by a terrifying, hopeless condition, she exerted an almost supernatural will to endure.

The reviewer is the author of several books on medical subjects, including "The Virus That Ate Cannibals."