Just about everyone swears on occasion. But some people are cursed with a pathological need to curseand uncontrollably shout obscenities every few minutes. Accompanied by a violent muscular tic, their singular malady is called the Gilles de la Tourette syndrome for the French neurologist who first described it in 1884. The disease is rare, but its smutty symptoms turn its victims into social pariahs, and sometimes the psychological disorder leads them to mental institutions.
Investigators strongly suspect that the tic is neurotic in origin, related to the venting of aggression. Beginning in children as muscular twitches, the La Tourette syndrome...