Cognitive dissonance in the placebo treatment of insomnia -- a pilot experiment.

Insomnia in 11 general hospital in-patients was treated by a placebo. The conditions of administration of the placebo were experimentally varied, and a hypothesis derived from Festinger's cognitive dissonance theory was tested. Consistent with this hypothesis, it was found that patients who were required to make meaningful decisions concerning their treatment derived significantly greater hypnotic (therapeutic) value from it than did patients whose treatment was simply administered to them and who were not required to make such decisions. The power of cognitive dissonance theory to explain the placebo effect, and the therapeutic potential of this approach are discussed.