Ray was a man possessed.

Every few seconds, he was seized and consumed by tics, grimaces, mannerisms, curses and compulsions of extraordinary violence.

His tics had cost him a dozen jobs, but he had found some sort of salvation as a superb weekend jazz drummer. He was famous, Oliver Sacks writes in The Man Who Mistook His Wife for a Hat, "for his sudden and wild extemporisations, which would arise from a tic or a compulsive hitting of a drum."

Dr. Sacks confirmed that Ray had the brain disorder called Tourette's syndrome, which is estimated to afflict one in a thousand people. He prescribed haldol, a drug that damps down the excitability of patients.

The next week, an angry Ray was back with a black eye and a broken nose. The drug had not removed the tics but had extended them enormously, often freezing him in "mid-tic." The haldol had also disrupted his reflexes: Trying to move through a revolving door, Ray had become disoriented and smashed his face.

"I've had these tics since I was four," a discouraged Ray told Sacks. "If you take them away, what then? I'm Witty Ticcy Ray. I've got my ticcy witticisms, my witty ticcisms. I have an identity as a ticcer."

There followed several months of consultation between patient and doctor, a period in which Ray had to evaluate both Tourette's perverse advantages and real disadvantages.

"A patient," says Sacks, "can be stuck into a negative identity, especially if they've had something for most of their lives and can hardly imagine life without it. Ray had to find a level of personality which was beneath Tourette's."

Ray's situation, while resembling that of another patient who only got migraines on Sunday, was of a different magnitude. "It's one thing having a migraine once a week, it's another having Tourette's 15 hours a day. Illness had entered into this life much more deeply."

Ray was eventually able to take haldol without any physical ill-effects. Yet the calming effect of the drug caused his drumming to lose its wild, innovative expressiveness. Now, it was merely adequate.

Ray's solution: Take haldol during the week, when he needed its dampening effects to hold down a job; and do without the drug on weekends, when he needed the syndrome to allow him to drum.

"All patients have different needs regarding the pitch at which they live," says Sacks. "The physiological problem here was to find some sort of happy medium between being too ticcy and too doped.

"It's the deepest part of a person that holds the balance."