Over a century and a half ago, a French physician reported the bizarre behavior of a young aristocratic woman who would suddenly, without warning, erupt in a startling fit of obscene shouts and curses. The image of the afflicted Marquise de Dampierre echoes through the decades as the emblematic example of an illness that today represents one of the fastest-growing diagnoses in North America. Tourette syndrome is a set of behaviors, including recurrent...