Even open-label placebos work, if they are explained -- ScienceDaily
For the first time, researchers from the University of Basel, along with colleagues from Harvard Medical School, have compared the effects of administering open-label and deceptive placebos. The team conducted an experimental study with 160 healthy volunteers who were exposed to increasing heat on their forearm via a heating plate. The participants were asked to manually stop the temperature rise as soon as they could no longer stand the heat. After that, they were given a cream to relieve the pain.
Some of the participants were deceived during the experiment: they were told that they were given a pain relief cream with the active ingredient lidocaine, although it was actually a placebo. Other participants received a cream that was clearly labeled as a placebo; they were also given fifteen minutes of explanations about the placebo effect, its occurrence and its effect mechanisms. A third group received an open-label placebo without any further explanation.
The subjects of the first two groups reported a significant decrease in pain intensity and unpleasantness after the experiment. "The previous assumption that placebos only work when they are administered by deception needs to be reconsidered," says Dr. Cosima Locher, a member of the University of Basel's Faculty of Psychology and first author of the study.