JIMMY'S mother is troubled. For the last few years her son has had strange and bizarre symptoms, and she cannot remember ever seeing another child behave the way he does. Jimmy was an average child until the age of 7 years, at which time his mother noted that he would often blink one eye out of synchrony with the other. She was told that this blinking was a nervous habit and was urged to ignore it. Unfortunately she could not, for other unusual "habits" began to appear. Within six months, Jimmy was uncontrollably twitching his nose, jerking his hand, and shrugging his shoulders. These mannerisms, while troublesome to Jimmy and his parents, were minor compared with those that followed: sniffing, throat clearing, barking and grunting noises, and finally, muffled words that sounded obscene. The tics subsided or went away completely for several months at a time. Because of Jimmy's continuing