Immediate-type hypersensitivity reactions and hypnosis: problems in methodology.

Hypnosis has been used to ameliorate skin test reactivity in studies dating back to the 1930s. This study using modern methodology and statistical analyses sets out to test the hypothesis that it was possible to decrease reactions to histamine by hypnotic suggestion. Five subjects, all asthmatic and untrained in hypnosis, were given three hypnotic sessions where they were asked to control their reactions to histamine administered by the Pepys technique to forearm skin. These sessions were to be compared with three non-hypnotic sessions. The flare sizes but not wheal sizes were found to be significantly reduced after the hypnosis sessions, compared to sessions without hypnosis. Skin temperature was correlated with the size of reactions. The day upon which the sessions took place contributed significant amounts of the remaining unexplained variance, giving rise to questions about what could cause these day to day changes.