The difference between the right word and the almost-right word is like the difference between the lightning and a lightning bug.-- Mark Twain
The Seattle Times recently ran an article on autism in which they mentioned that:
... a theory that thimerosal is to blame has been repeatedly discounted in scientific studies. (my emphasis)
I'm pretty sure from context that the journalist meant to say that the thimerosal link was unsupported, disproved, or possibly even debunked by scientific studies. But the one thing those studies didn't do was discount it, since that would indicate that they had dismissed it out of hand without considering the evidence!