, a substance that works to neutralize free radicals in the body. As noted above, it has been suggested that free-radicals may play a role in TD. If this is true, it makes sense that vitamin E might help prevent or treat the condition.
Between 1987 and 1998, at least five
were published which indicated that vitamin E was beneficial in treating TD.
Although most of these studies were small and lasted only 4 to 12 weeks, one 36-week study enrolled 40 people.
Three small double-blind studies reported that vitamin E was not helpful.
Nonetheless, a statistical analysis of the double-blind studies done before 1999 found good evidence that vitamin E was more effective than placebo.
Most studies found that vitamin E worked best for TD of more recent onset.
However, in 1999, the picture on vitamin E changed with the publication of one more study—the largest and longest to date.
This double-blind study included 107 participants from nine different research sites who took 1,600 IU of vitamin E or placebo daily for at least 1 year. In contrast to most of the previous studies, this trial failed to find vitamin E effective for decreasing TD symptoms.
Why the discrepancy between this study and the earlier ones? The researchers, some of whom had worked on the earlier, positive studies of vitamin E, were at pains to develop an answer.
They proposed a number of possible explanations. One was that the earlier studies were too small or too short to be accurate, and that vitamin E really didn’t help at all. Another was the most complicated: that vitamin E might help only a subgroup of people who had TD—those with milder TD symptoms of more recent onset—and that fewer of these people had participated in the latest study. They also pointed to changes in schizophrenia treatment since the last study was done, including the growing use of antipsychotic medications that do not cause TD.
The bottom line:
The effectiveness of vitamin E for a given person is simply not known. Given the lack of other good treatments for TD, and the general safety of the vitamin, it may be worth discussing with your physician.
For more information, including dosage and safety issues, see the full