Tourette syndrome (TS) is an inherited disease of the nervous system, first described more than a century ago by the pioneering French neurologist, Dr. George Gilles de la Tourette. Before age 18, patients with TS develop motor tics, that is, repeated, jerky, stereotyped, purposeless muscle movements in almost any part of the body. Vocal tics occur in the form of loud grunting or "barking" noises or, in some cases, words or phrases. In most cases, the tics come and go, and they often are replaced by different types of sounds or movements, which may become more complex as the patient grows older.

TS is three times more common in men than in women. The motor tics, which usually occur in bouts several times a day, may make it very hard for the patient to perform simple acts like tying shoelaces, not to mention work-related tasks or driving...