From the New York Magazine:
“It’s a mystery of modern medicine: Americans — and only Americans — are becoming more likely to report feeling very real physical effects after taking totally fake painkillers, say scientists from McGill University. According to their findings, published this week in the journal Pain, the placebo effect has gotten stronger since the early 1990s, but only in drug trials conducted within the U.S. — not ones conducted in Europe or Asia.
The researchers have zeroed in on two potential explanations.
First, the U.S. is one of only two countries worldwide in which drug companies are allowed to advertise directly to consumers. (The other is New Zealand.)
But the more important answer, the researchers think, may lie in the fact that clinical trials in the U.S. grew longer and included more participants over the two decades studied here… And as these trials have grown, they’ve added more non-pharmaceutical aspects, such as hiring nurses to consult with the trial participants, Jeffrey Mogil, who led the study, told Nature. All of these factors may infuse the entire experience with an official, legitimized kind of feeling, which may also be contributing to the rise in placebo effectiveness.” (emphasis added)
Here’s an interesting, ethical question, if advertising drugs makes them more effective, should it be allowed more, even encouraged?