PainSci summary of Locher 2017?This page is one of thousands in the PainScience.com bibliography. It is not a general article: it is focused on a single scientific paper, and it may provide only just enough context for the summary to make sense. Links to other papers and more general information are provided at the bottom of the page, as often as possible. ★★★★☆?4-star ratings are for bigger/better studies and reviews published in more prestigious journals, with only quibbles. Ratings are a highly subjective opinion, and subject to revision at any time. If you think this paper has been incorrectly rated, please let me know.
A couple of scientific papers (eg Kaptchuk) have suggested that deception isn’t necessary for a placebo to work. That is, they may be effective even when people know that they are placebo. However, this study challenges that hypothesis by demonstrating that deceptive placebo only work if you replace the deception with some other reason for the patient to have faith in it.
They compared four groups of about 40 patients each, with one (control) group getting nothing at all, and the other three all receiving a placebo cream presented in a different way:
- a deceptive placebo: “this cream is medicine”
- open-label without rationale: “this cream is a placebo”
- open-label with rationale: “this cream is placebo, but it will help you, because placebo is potent”
Subjects were tested for heat-pain tolerance. By objective measures, everyone was the same, but there were differences when measured subjectively. Groups 1 and 3 were both given a reason to believe the cream would work, and they both experienced the same reduced intensity and unpleasantness; group 2 got no benefit. Thus the authors conclude that “placebos with a plausible rationale are more effective than without a rationale.” Translation: expectation of efficacy is the active ingredient, whether it is achieved with deception or exaggeration of the power of placebo.
original abstract†Abstracts here may not perfectly match originals, for a variety of technical and practical reasons. Some abstacts are truncated for my purposes here, if they are particularly long-winded and unhelpful. I occasionally add clarifying notes. And I make some minor corrections.
Research on open-label placebos questions whether deception is a necessary characteristic of placebo effects. Yet, comparisons between open-label and deceptive placebos (DPs) are lacking. We therefore assessed effects of open-label placebos and DPs in comparison with no treatment (NT) with a standardized experimental heat pain paradigm in a randomized controlled trial in healthy participants. Participants (N = 160) were randomly assigned to NT, open-label placebo without rationale (OPR-), open-label placebo with rationale (OPR), and DP. We conducted baseline and posttreatment measurements of heat pain threshold and tolerance. Apart from the NT, all groups received an application of a placebo cream. Primary outcomes were planned comparisons of heat pain tolerance and the corresponding intensity and unpleasantness ratings. Objective posttreatment pain tolerance did not differ among groups. However, for subjective heat pain ratings at the posttreatment tolerance level, groups with a rationale (OPR and DP) reported diminished heat pain intensity (t(146) = -2.15, P = 0.033, d = 0.43) and unpleasantness ratings (t(146) = -2.43, P = 0.016, d = 0.49) compared with the OPR- group. Interestingly, the OPR and the DP groups did not significantly differ in heat pain intensity (t(146) = -1.10, P = 0.272) or unpleasantness ratings (t(146) = -0.05, P = 0.961) at the posttreatment tolerance level. Our findings reveal that placebos with a plausible rationale are more effective than without a rationale. Even more, open-label placebos did not significantly differ in their effects from DPs. Therefore, we question the ubiquitously assumed necessity of concealment in placebo administration.
- “Placebos without deception: a randomized controlled trial in irritable bowel syndrome,” an article in PLoS ONE, 2010.
- “Open-label placebo treatment in chronic low back pain: a randomized controlled trial,” an article in Pain, 2016.
One article on PainScience.com cites Locher 2017 as a source:
- PS Placebo Power Hype — The placebo effect is fascinating, but its “power” isn’t all it’s cracked up to be
This page is part of the PainScience BIBLIOGRAPHY, which contains plain language summaries of thousands of scientific papers & others sources. It’s like a highly specialized blog. A few highlights:
- A Bayesian model-averaged meta-analysis of the power pose effect with informed and default priors: the case of felt power. Gronau 2017 Comprehensive Results in Social Psychology.
- Association of Spinal Manipulative Therapy With Clinical Benefit and Harm for Acute Low Back Pain: Systematic Review and Meta-analysis. Paige 2017 JAMA.
- Incidence of Spontaneous Resorption of Lumbar Disc Herniation: A Meta-Analysis. Zhong 2017 Pain Physician.
- How much is too much? (Part 1) International Olympic Committee consensus statement on load in sport and risk of injury. Soligard 2016 Br J Sports Med.
- Chiropractic spinal manipulative therapy for migraine: a three-armed, single-blinded, placebo, randomized controlled trial. Chaibi 2016 Eur J Neurol.