While researchers usually use placebos in clinical trials to test the effectiveness of a new treatment, this trial pitted one placebo against another. "It's upside down research," said Ted Kaptchuk, assistant professor of medicine and associate director of the Division for Research and Education in Complementary and Integrative Medical Therapies and the Osher Institute at Harvard Medical School. "We investigated whether a sham acupuncture device has a greater placebo effect than an inert pill."
The study of 270 individuals with chronic arm pain had two phases. In the first phase, 135 patients were given sham acupuncture, and another 135 patients were given a placebo pill for two weeks. During this period, investigators found no strong evidence for an enhanced effect with placebo devices compared with placebo pills.
In the second phase of the study, the same patients were randomized again, with half the patients entered in a sham acupuncture device versus real acupuncture trial, and the other half in a placebo pill vs. real pain pill trial. The acupuncture trial extended four more weeks (the length believed needed to see improvement), and the pill trial lasted six more weeks (the length needed to have the real drug in the bloodstream).
In the second phase of the study, patients receiving sham acupuncture reported a more significant decrease in pain and symptom severity than those receiving placebo pills for the duration of the trials. The results of this study show that the placebo effect varies by type of placebo used.
"These findings suggest that the medical
Source:Harvard Medical School