Improvement of the tic syndrome of Gilles de la Tourette by haloperidol suggests that brain dopaminergic functions may be hyperactive in this condition. The role of catecholamines in Tourette syndrome was tested by administration to seven patients of alpha methyl para tyrosine (MPT), which inhibits synthesis, or tetrabenazine, which inhibits storage of brain catecholamines.
Two patients improved with each medication but only one each enjoys sustained benefit. Adverse effects were drug crystalluria with MPT and extrapyramidal effects with both medications. Intravenously given cholinergic and anticholinergic medication had no consistent effect on tics. The MPT and tetrabenazine are not satisfactory medications, but their effects suggest that brain catecholamines may be important in Tourette syndrome.
Sweet RD, Bruun R, Shapiro E, Shapiro AK. Presynaptic Catecholamine Antagonists as Treatment for Tourette SyndromeEffects of Alpha Methyl Para Tyrosine and Tetrabenazine. Arch Gen Psychiatry. 1974;31(6):857-861. doi:10.1001/archpsyc.1974.01760180095012