brand logo

Am Fam Physician. 2017;95(7):456-457

Clinical Question

Can simply telling patients that a medicine works, even if it is placebo, decrease pain and improve disability in patients with chronic low back pain?

Bottom Line

These investigators gave twice daily placebo to patients with chronic back pain and told them it was placebo. They also told them that placebos can have a pronounced effect (which is true). The addition of placebo to usual care improved patients' pain and disability scores over the three weeks of the study. Although we probably will not start prescribing placebo, this study emphasizes the great value of conveying one's confidence in the treatment to bolster its effect. (Level of Evidence = 2b)


These investigators, who conducted the study in Portugal, enrolled 83 patients who had experienced low back pain for at least three months and responded to an advertisement. Most (87%) were taking analgesia, approximately 40% were taking adjuvant medication (e.g., gabapentin [Neurontin] or a muscle relaxant), and approximately 20% were taking an antidepressant. The authors excluded patients with severe fibromyalgia or rheumatoid arthritis and those who had received opioid treatment in the past. For three weeks, patients were asked to continue their usual treatment. Using concealed allocation, one-half of the patients were also given two placebo tablets twice a day. They were told that it was an inactive placebo, but: (1) it could still have a powerful effect; (2) the body can automatically respond to placebo; (3) a positive attitude is helpful but not necessary; and (4) the placebo must be taken faithfully. Knowingly taking placebo significantly decreased maximum reported pain, minimum reported pain, and usual pain compared with usual therapy only. Back pain–related disability was also decreased with placebo. There were several problems with the study, however: unbalanced baseline pain, small numbers in each group, and the lack of a commercially available placebo.

Study design: Randomized controlled trial (nonblinded)

Funding source: Government

Allocation: Concealed

Setting: Outpatient (any)

Reference:Carvalho C, Caetano JM, Cunha L, Rebouta P, Kaptchuk TJ, Kirsch I. Open-label placebo treatment in chronic low back pain: a randomized controlled trial. Pain. 2016;157(12):2766–2772.

POEMs (patient-oriented evidence that matters) are provided by Essential Evidence Plus, a point-of-care clinical decision support system published by Wiley-Blackwell. For more information, see Copyright Wiley-Blackwell. Used with permission.

For definitions of levels of evidence used in POEMs, see

To subscribe to a free podcast of these and other POEMs that appear in AFP, search in iTunes for “POEM of the Week” or go to

This series is coordinated by Natasha J. Pyzocha, DO, contributing editor.

A collection of POEMs published in AFP is available at

Continue Reading

More in AFP

More in PubMed

Copyright © 2017 by the American Academy of Family Physicians.

This content is owned by the AAFP. A person viewing it online may make one printout of the material and may use that printout only for his or her personal, non-commercial reference. This material may not otherwise be downloaded, copied, printed, stored, transmitted or reproduced in any medium, whether now known or later invented, except as authorized in writing by the AAFP.  See permissions for copyright questions and/or permission requests.