Effects of medication strongly affected by what you are told about them
Six pages on PainSci cite Flaten 1999: 1. The Complete Guide to Trigger Points & Myofascial Pain 2. The Complete Guide to Low Back Pain 3. The Complete Guide to Chronic Tension Headaches 4. The Complete Guide to Neck Pain & Cricks 5. Complete Guide to Frozen Shoulder 6. Cramps, Spasms, Tremors & Twitches
PainSci commentary on Flaten 1999: ?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 wherever possible.
How much does the effect of a medication depend on what you are told about it? Quite a bit, apparently! This strange and fascinating study in Psychosomatic Medicine showed that a muscle relaxant actually increases tension when the patient is told (lied to) that it is actually a stimulant. The false information is so potent — or the drug is so weak — that its intended effect is actually reversed.
It’s like a Jedi mind trick. These aren’t the drugs you’re looking for.
But the reverse was not true: even when told that they were taking a muscle relaxant (and they were), subjects did not actually relax any more than people taking a placebo … and in some cases less!
And there’s more. This study contains many odd gems, such as the bizarre fact that quite a lot more muscle relaxant was found in the blood of people who had been told that the muscle relaxant was a muscle relaxant. It appears that they literally soaked up more of the stuff from the GI tract when they believed that it was a relaxant! And yet it still didn’t actually relax them any more than a 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.
OBJECTIVE: Administration of the muscle relaxant carisoprodol and placebo was crossed with information that was agonistic or antagonistic to the effect of carisoprodol. It was investigated whether information alone induced physiological and psychological responses, and whether information modified the response to the drug.
METHODS: Half of the subjects received capsules containing 525 mg carisoprodol together with information that the drug acted in a specific way (Groups Relaxant/C, Stimulant/C, and No Information/C). The other half of the subjects received lactose (Groups Relaxant/L, Stimulant/L, and No Information/L). Dependent variables were blink reflexes and skin conductance responses, subjective measures of tension and sleepiness, and serum carisoprodol and meprobamate concentrations. Recordings were made between 15 and 130 minutes after administration of the capsules.
RESULTS: The Stimulant/L group reported more tension compared with the other two groups, and carisoprodol increased tension even more in the Stimulant/C group. The Relaxant/C group displayed higher levels of carisoprodol serum concentration compared with the other groups that received carisoprodol.
CONCLUSIONS: Reported tension was modulated in the direction suggested by the stimulant information. The effect of carisoprodol on tension was also modulated by stimulant information. Increased carisoprodol absorption in the group that received relaxant information could be a mechanism in the placebo response.
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:
- Topical glyceryl trinitrate (GTN) and eccentric exercises in the treatment of mid-portion achilles tendinopathy (the NEAT trial): a randomised double-blind placebo-controlled trial. Kirwan 2024 Br J Sports Med.
- Placebo analgesia in physical and psychological interventions: Systematic review and meta-analysis of three-armed trials. Hohenschurz-Schmidt 2024 Eur J Pain.
- Recovery trajectories in common musculoskeletal complaints by diagnosis contra prognostic phenotypes. Aasdahl 2021 BMC Musculoskelet Disord.
- Cannabidiol (CBD) products for pain: ineffective, expensive, and with potential harms. Moore 2023 J Pain.
- Moderators of the effect of therapeutic exercise for knee and hip osteoarthritis: a systematic review and individual participant data meta-analysis. Holden 2023 The Lancet Rheumatology.