The pharmacological treatment of Tourette Syndrome and tic disorders is often limited by unwanted side effects. In particular, moderate-tosevere tic disorders generally require treatment with antipsychotics, which often produce cognitive dulling and dysphoria. Metoclopramide is a dopamine antagonist similar to antipsychotic medications. However, it seems to have different effects in certain brain regions than traditional antipsychotic medications. Its profile suggests efficacy in the treatment of tic disorders with minimal cognitive and affective adverse effects. Anecdotal clinical experience supports this hypothesis, but there have been no controlled studies of metoclopramide in the treatment of tic disorders. The purpose of this study is to evaluate the efficacy and tolerability of metoclopramide in children and adolescents with Tourette Syndrome or chronic tic disorders. Thirty patients aged 7 to 17 years will be randomly assigned to receive either metoclopramide or placebo for 56 days. Metoclopramide will be initiated at a dose of 5 mg/day and flexibly titrated to a maximum of 40 mg day. Behaviourial ratings, completed at baseline and 2,4,6, and 8 weeks after the initiation of the study, will include the Yale Global Tic Severity Scale, the Clinical Global Impressions Severity Scale for Tourette’s Syndrome, the Drug Attitude Inventory, the Yale-Brown Obsessive-Compulsive Scale, and the Conners Parent Rating Scale. We hypothesize that metoclopramide will be significantly more effective than placebo in the treatment of tic disorders, and that there will be no significant difference between metoclopramide and placebo in terms of cognitive and affective adverse effects. If these hypotheses were confirmed, they could provide support for Metoclopramide as an effective treatment for tic disorders with less treatment-limiting side effects. Rob Nicolson, M.D. University of Western Ontario, London, Ontario, Canada Award: $22,345 Tourette Association of America Inc. – Research Grant Award 2001-2002