Placebos without deception: a randomized controlled trial in irritable bowel syndrome.
Kaptchuk TJ, Friedlander E, Kelley JM, Sanchez MN, Kokkotou E, Singer JP, Kowalczykowski M, Miller FG, Kirsch I, Lembo AJ. PLoS One. 2010;5(12):e15591.
https://www.ncbi.nlm.nih.gov/pubmed/21203519 (Free Text Available for All)
You may have seen news highlights related to this recent article. The researchers tested the hypothesis that the placebo effect requires patient deception; making patients believe that the treatment will work. The study compared two randomized groups of patients with irritable bowel syndrome, a common chronic gastrointestinal disorder (80 participants total). One group received placebos (instructed that they were placebo pills and that placebo pills are beneficial) and the other group received no treatment but had similar interactions with their clinician (it would have been interesting to see a third group that took a placebo unknowingly). After 11 days and 22 days (the total length of the trial) the group receiving the placebo was doing better than those with no treatment (based on a basic self-reported symptom improvement score). There was two major sources for potential bias, which may have exaggerated the findings: 1) the no-treatment group was advised prior to the study that placebos are therapeutically beneficial, and 2) the placebo group was told that their intervention would work (the participants could have provided answers that they thought the researchers wanted to hear). More studies will be needed to verify these findings and determine how applicable they are to other patient populations.
This is an interesting article because it highlights the importance of explaining a treatment to a patient (even if it’s a placebo) and the significance of receiving (or taking) an intervention ritually. This study was not able to assess the benefit of extra attention from the clinician but this could contribute to improvement in both groups. Previous studies exploring the effect of placebos have had positive outcomes (particularly with subjective outcomes like pain). We should also consider these findings in light of emerging research that links the brain to inflammation/immune responses throughout the body (for example, depression increasing systemic inflammation and vice versa). More research is definitely needed to clarify the full potential of the placebo effect but as clinicians it may be beneficial for us to spend a little more time with our patients, talking to them about their injury and health, discussing why their treatments are important, and encouraging them to do their treatments (medicines or exercise) regularly. As we get pushed to see more and more patients in a shorter period of time this can be a challenge but the benefits may be considerable.
For an additional article discussing the clinical implications of the placebo effect I recommend Doherty and Dieppe’s 2009 paper in Osteoarthritis and Cartilage: (https://www.ncbi.nlm.nih.gov/pubmed/19410027)
Written by: Jeffrey Driban
Reviewed by: Stephen Thomas