Differential effects of hypnotic suggestion on multiple dimensions of pain

Within the framework of multidimensional pain assessment, this study extended an earlier finding that hypnotic analgesia and relaxation suggestions have differential effects on pain reduction by evaluating these strategies in subjects undergoing a cold pressor protocol. Thirty-two highly susceptible subjects were randomly assigned to an analgesia or a relaxation suggestion treatment group. Six pain reports were taken at 10-sec intervals for each experimental condition. The baseline measures served as covariates. A 2 x 2 x 2 x 6 repeated-measures analysis of covariance (ANCOVA) revealed a significant group (analgesia, relaxation) by pain dimension (intensity, unpleasantness), by condition (suggestion alone, hypnotic induction plus suggestion) interaction. Analysis of the simple-simple main effects, holding both group and condition constant, revealed that application of hypnotic analgesia reduced report of pain intensity significantly more than report of pain unpleasantness. Conversely, hypnotic relaxation reduced pain unpleasantness more than intensity. The clinical implications of the study are discussed.