Placebo, Suggestion, and Pain
The placebo effect is a powerful tool. Although the exact workings of the effect are unknown, all clinicians know that a certain percentage of patients will respond to therapy—even if the therapy is not a real one.
A recent study took the concept of placebo one step further by examining the role of suggestion on pain threshold. Sixty college students were involved in the study, and were split into three groups of 20. All sixty subjects were to place their hand in a tank of ice water at a temperature of 1°C. For the first immersion, the subjects were told nothing except to remove their hand when the pain was unbearable.
For the second immersion, the only thing that differed between the three groups was the instructions the subjects received before the hand immersion:
- The control group was told neutral things about the experiment: Don't think about anything, don't do anything special. Just keep you hand in the water until you want to remove it.
- The "positive placebo-intervention" group was told about the benefits of ice water immersion: it "increases circulation, exercises blood vessels, strengthens the heart, tightens the skin pores, and cleanses the skin cells..." among other positive effects.
- The "negative placebo-intervention" group was told the dangers of ice water immersion. "It can cause numbness in hand and fingers, loss of sensation, constriction of blood vessels, decrease in blood flow to the brain, and induce hypertension; it can promote frost bite, swelling of the finger joints," etc.
All three groups were directed to keep hand immersed until they couldn't tolerate the pain any longer. The researchers measured how long it took for the subjects to register discomfort and how long they kept their hand in the ice water. They compared the results for the first and second immersions.
The researchers found significant differences between the groups:
- There was no difference in results for the control group subjects who were given neutral instructions.
- For the "positive" intervention group, there was a significant increase in threshold and endurance to the immersion.
- And for the "negative" intervention group, there was a dramatic decrease in the endurance of pain and in pain thresholds.
- Anxiety was decreased for the "positive" group, but increased for the "negative" subjects.
The results of this study are of great importance to anyone who works with patients experiencing pain or discomfort. The suggestions that a clinician makes can have a dramatic effect on how the patient will respond:
"A pill can act as a placebo suggestion. The same is true of the words uttered by the physician. The present study indicates that such words can be crucial in the treatment of pain. For just as they can serve a therapeutic effect by decreasing pain and pain behavior, the physician who says things that elicit a negative emotional response in the patient can increase the patient's pain and the patient's pain behavior."
Staats P, Hekmat H, Staats A. Suggestion/placebo effects on pain: negative as well as positive. Journal of Pain and Symptom Management 1998;15(4):235-243.
Please note that this article is copyrighted and may not be reproduced without permission. To include our articles and videos on your website, check out our chiropractic website service.