The neurological disorder Gilles de la Tourette syndrome is most often treated with the receptor blocker haloperidol, which also produces multiple side-effects, including the risk for tardive dyskinesia. In placebo control double-blind studies, two other neuroleptic drugs, fluphenazine and trifluoperazine, were found to be as efficaceous as haloperidol, but with fewer side-effects. In other studies, clonidine was shown to be equally efficaceous with haloperidol, but did not produce adverse central nervous system side-effects. To treat the extrapyramidal side-effects accompanying the treatment of Tourette syndrome with neuroleptic agents, amantadine and benztropine were compared in a crossover study. It was demonstrated that amantadine is a superior agent in treating the side effects of haloperidol treatment in Tourette syndrome. The use of lithium was without significant action upon lessening the tics of Tourette syndrome.