Hypnosis, hypnotizability, and placebo

Dr. Raz's speculations about the relation between placebo responsivity and hypnotizability are critically examined. While there is no generally accepted theoretical definition of hypnosis, there is a general consensus that hypnotizability can be reliably measured. In contrast, there seems to be a general consensus about a theoretical definition of placebo (including placebo effect, placebo response, and nocebo). There is no widely accepted measure of individual differences in placebo responsivity. Various methodological considerations about how to examine the relation between placebo responsivity and hypnotizability are identified. Studies are identified which indicate that response to treatments which utilize adjunctive hypnosis are superior to placebo treatments. The only study which examined whether placebo responsivity was correlated with hypnotizability seems to indicate that they are only slightly related at best. The possibility that there may be such thing as a "good placebo responder (GPR)" is questioned, while the known clinical value of hypnotizability assessment is reaffirmed. Future directions for empirical research on the relation between placebo responsivity and hypnotizability are identified.