http://www.guardian.c...ct-patients-sham-drug
In a trial of 80 patients with IBS, half the people were given a placebo and "Not only did we make it absolutely clear that these pills had no active ingredient and were made from inert substances, but we actually had 'placebo' printed on the bottle." said the professor in charge of the test.
"By the end of the trial, almost twice as many patients treated with placebo showed adequate relief of symptoms compared with the control group. Patients taking the placebo also doubled their average rate of improvement to that achieved with the most powerful IBS medications."
In other words just giving the patents something to take, even though they knew that it should be ineffective, gave positive results.
Is this just a statistical anomaly because of the sample size? Have there been any previous studies of a similar nature where the patients know that they are getting the placebos? (did a quick search but couldn't see anything)