Tic disorders affect 4-18% of children at some stage of their development.1 At one end of the spectrum are children with brief episodes of single tics, whereas at the other are children with chronic multiple tics, including Tourette's syndrome. Tics are abrupt and recurrent motor or vocal actions. Although involuntary, they may be preceded by a sensory urge, are sometimes suppressed for prolonged periods, or can even be triggered by external perceptions. They are sudden and purposeless. They can be divided into simple tics such as blinking, shrugging of the shoulders, grunting, and clearing one's throat, and complex tics such as licking, jumping, or touching objects. Tourette's syndrome is the most severe form, with multiple motor and vocal tics lasting for a year or more.2

The best known symptom of Tourette's syndrome, coprolalia (a complex vocal tic with involuntary swearing), occurs in less than 15%.3 This unusual symptom has contributed to the view that Tourette's requires extraordinary …