METHODS: Thirty-six patients with abnormal involuntary movements meeting research criteria for TD, who are on stable doses of psychotropic medications, will be randomized to receive galantamine alternating with placebo in addition to their standard medications. After 2 baseline measurements, each patient will undergo 12-week treatment periods of galantamine and placebo with a 4-week washout period between treatments. Patients will be evaluated every 2 weeks throughout the study, using standardized rating scales for TD (AIMS) and other extrapyramidal side effects (SIMPSON, BARNES. During the active treatment period, patients will receive galantamine 4 mg BID for 4 weeks followed by 8 mg BID for 4 weeks, and 12 mg BID for an additional 4 weeks. Placebo-galantamine differences will be examined by repeated measures analysis of covariance for a two-period crossover design.