Safety and Efficacy of Pyridoxal 5' -Phosphate in the Treatment of Tardive Dyskinesia

This study will assess the effect of Pyridoxal 5'-Phosphate on the reduction of expressed symptoms of moderate to severe tardive dyskinesia in patients with schizophrenia and schizoaffective disorders who are on a stable dose, and regime, of either a long acting (i.e. depot/IM) or oral antipsychotic medication, as compared to placebo. Symptoms will be assessed through the administration and scoring of Abnormal Involuntary Movement Scale (AIMS), specifically on items 1 through 7 (facial and oral movements, extremity movements and trunk movements) at each visit.