The Effectiveness of Hypnoanalgesia Using Conventional and Placebo Hypnosis Induction.

The effectiveness of hypnosis-based pain management is well-established. However, mechanisms of action and specific effective components are not well understood. The sociocognitive theory of hypnosis proposes that the effectiveness of hypnosis for pain management is determined by the nonspecific features of response expectancy and context. We tested this claim by contrasting the effectiveness of 2 hypnoanalgesia procedures in a within subjects design using the cold pressor task. The 2 procedures were identical, including analgesic suggestions, except for the hypnosis induction used. One condition involved a well-established hypnosis induction, including suggestions for focused attention, relaxation, and deepening. The other condition included a sham induction procedure using only white noise. In our confirmatory analysis (N = 46), we found that pain tolerance increased compared to baseline equivalently in the conventional and sham induction conditions (mean increase 13.7 and 12.4 seconds respectively, average within subject difference -1.27 seconds, 90% confidence interval [CI] = -8.46, 5.90). This finding supports the claim of the sociocognitive theory considering that response expectancy for pain reduction was also equivalent between the conditions (average difference 2.30, 90% CI = -2.23, 6.84). However, self-reported hypnosis depth was greater in the conventional induction condition (average difference -.78, 90% CI: -1.36, -.07), which contradicts sociocognitive predictions. Our findings indicate that conventional procedural elements of hypnosis inductions, such as suggestions for focused attention, relaxation, and deepening, may not be necessary to achieve acute pain reduction in an experimental setting when the hypnosis intervention includes analgesic suggestions. PERSPECTIVE: This study assessed the necessary effective components of hypnosis-based analgesia interventions. Our findings suggest that procedural features such as suggestions for focused attention, relaxation, and deepening may not be necessary for hypnoanalgesia as long as pain relief suggestions are present, and the hypnosis context and response expectancy are established. TRIAL REGISTRATION: This trial was registered on Open Science Framework with the registry number e96xk, available at https://osf.io/e96xk.