Vitamin E in extrapyramidal disorders.

In this article the effect of vitamin E on two extrapyramidal disorders, tardive dyskinesia and Parkinson's disease, is reviewed. After a brief description of the symptoms, the current hypotheses for the pathogenesis of these diseases are described. A summary of the clinical research that has been done to establish the effectiveness of vitamin E is given. In tardive dyskinesia four clinical trials (double-blind, placebo-controlled) showed improvement in the symptoms with vitamin E in doses of up to 1,600 IU/day. Preliminary studies concerning Parkinson's disease suggested that vitamin E (2,000 IU/day) probably cannot prevent the development of the disease. It was suggested that vitamin E is able to slow the progression of the illness. The results from a large double-blind, placebo-controlled clinical trial, however, did not show any beneficial effect of vitamin E in Parkinson's disease.