Levetiracetam in the Treatment of Neuroleptic-induced Tardive Dyskinesia

Inclusion Criteria: * Subjects between ages 18 and 80 years * Subjects must have a diagnosis of stable axis I psychiatric disorder at least 6 months prior to screening * Subjects must have a stable neuroleptic-induced tardive dyskinesia at least 1 month prior to screening and meet tardive dyskinesia severity criteria * Subjects must have used antipsychotics for at least 6 cumulative months, and, be on a stable dose for 1 month prior to screening Exclusion Criteria: * Presence of any axis II condition within 6 months prior to screening * Huntington´s disease, idiopathic dystonia, Wilson´s disease, Sydenham´s chorea, thyroid dysfunction, spontaneous dyskinesia * Start of drugs-other than neuroleptics- that can cause dyskinesia * Presence of additional major disease such as cardiac, renal or hepatic dysfunction or terminal illness