The effects of hypnotic and nonhypnotic imaginative suggestion on pain

Few studies have compared placebo and suggested pain reduction.

Hypnotic and nonhypnotic imaginative analgesia suggestions were compared against a placebo in reducing experimental pain. The mediator role of response expectancies and the moderator role of hypnotic and nonhypnotic imaginative suggestibility were evaluated.

Sixty participants previously assessed for hypnotic and nonhypnotic imaginative suggestibility were assigned to one of two experimental conditions or a no-treatment control condition. In the "placebo first" condition, participants received placebo, followed by imaginative and then hypnotic analgesia suggestions. In the "placebo last" condition, participants received imaginative and then hypnotic suggestions, followed by placebo.

Imaginative and hypnotic suggestions did not differ significantly and were more effective than no treatment in reducing pain. The placebo was no different from the analgesia suggestions and was more effective than no treatment, but only when administered after the suggestions. Pain reduction was mediated by expectancy but was not significantly related to suggestibility or hypnotizability, the latter operationalized as hypnotic suggestibility with imaginative suggestibility statistically controlled.

In the general population, nonhypnotic imaginative suggestions may be as effective as hypnotic suggestions in reducing pain. Response expectancies would seem to be an important mechanism of placebo and suggested pain reduction.