For decades it was thought that the power of the placebo effect resided in the belief that patients were receiving, or at least could receive, pharmacologically active treatment. A new study by doctors and researchers at the Beth Israel Deaconess Medical Center suggests that patients need not be fooled to benefit from placebo treatment.
Published in a randomized clinical trial in the journal PAINThe researchers found that participants with moderate to severe irritable bowel syndrome (IBS) who were knowingly treated with a pharmacologically inactive pill – called an honest or open-label placebo – reported clinically meaningful improvements in their IBS symptoms. More than two-thirds (69%) of participants who received the open-label placebo showed improvements that were significantly greater than those reported by participants assigned to a no-pill control group. There was no difference in symptom improvement between those who received open or double-blind placebos. The results build on the previous findings of the research team and challenge the long-standing notion that concealment or deception are key elements of the placebo effect.
The strictly designed clinical study took part in 262 adult participants aged 18 to 80 years with at least moderate IBS. Participants were examined, questionnaires completed, and randomized into one of three study arms – open placebo; Double-blind (including double-blind placebo or double-blind peppermint oil); or no pill control. During their investigations, all participants discussed the placebo effect, the study and its goals with their doctors.
The open label group received pill vials labeled “Open Label Placebo” and learned that the pills they contained were pharmacologically inert, but could feel better thanks to the placebo effect. The double-blind group received pill bottles labeled “double-blind placebo or peppermint oil”. The participants in the double-blind group received either a placebo or an identical pill with peppermint oil, but neither they nor the research team knew which they were receiving. All participants who received pills were instructed to take one pill three times a day 30 minutes before meals. The no-pill control group received no pills, but otherwise followed an identical study protocol.
According to one of the leading researchers, many theories about the mechanisms that produce placebo effects may need to be changed if the assumption that deception is necessary for placebos to work is wrong.
Edited by Gary Cramer