Enhancing placebo effects: insights from social psychology.

Placebo effects are widely recognized as having a potent impact upon treatment outcomes in both medical and psychological interventions, including hypnosis. In research utilizing randomized clinical trials, there is usually an effort to minimize or control placebo effects. However, in clinical practice there may be significant benefits in enhancing placebo effects. Prior research from the field of social psychology has identified three factors that may enhance placebo effects, namely: priming, client perceptions, and the theory of planned behavior. These factors are reviewed and illustrated via a case example. The consideration of social-psychological factors to enhance positive expectancies and beliefs has implications for clinical practice as well as future research into hypnotic interventions.