The Effect of a Placebo on the Perception of Painful Radiant Heat Stimuli

Sensitivity to painful thermal stimuli and willingness to report pain were studied in two experimental sessions. No treatment was given during the first session, but on the second session a placebo was administered as a potent, fast-acting analgesic. The placebo failed to affect sensitivity to thermal stimulation, but significant decreases in willingness to report pain were observed. A side effects questionnaire showed that a significant number of side effects were reported by subjects on the placebo session.