, 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 le