The placebo effect seems to be appearing stronger than in past years, causing the percentage of new pharmaceutical products failing their effectiveness trials to grow. If a drug is unable to provide relief significantly better than a sugar pill, it won't go on the market.

The upshot is fewer new medicines available to ailing patients and more financial woes for the beleaguered pharmaceutical industry. Last November, a new type of gene therapy for Parkinson’s disease, championed by the Michael J. Fox Foundation, was abruptly withdrawn from Phase II trials after unexpectedly tanking against placebo. A stem-cell startup called Osiris Therapeutics got a drubbing on Wall Street in March, when it suspended trials of its pill for Crohn’s disease, an intestinal ailment, citing an “unusually high” response to placebo. Two days later, Eli Lilly broke off testing of a much-touted new drug for schizophrenia when volunteers showed double the expected level of placebo response.

It isn't only trials of new drugs which are proving less effective. Some products which have been on the market for decades, like Prozac, are starting to falter in more recent follow-up tests.

Wired takes a closer look at how the placebo effect works, and the many reasons why newer drugs can't work as well as the mind's ability to affect the body.

[Wired via Neatorama]