The Nature of Hypnotic Analgesia and Placebo Response to Experimental Pain
THOMAS H. McGLASHAN, MD,* FREDERICK J. EVANS, PhD, and MARTIN T.
ORNE, MD, PhD
The effects of hypnotically induced analgesia and placebo response to "a powerful
analgesic drug" were investigated. Highly motivated Ss, who were either very responsive
or essentially insusceptible to hypnosis, performed a task which induced ischemic muscle
pain. Special procedures and a modified double-blind condition were adopted to establish
plausible expectations in both groups that the two treatments effectively reduce pain
intensity. Changes in pain threshold and tolerance following hypnotic and placebo
analgesia (compared to an initial base-level performance), were evaluated and were
related to changes in the Ss' subjective ratings of pain intensity. The results support the
hypothesis that there are two components involved in hypnotic analgesia: One component
can be accounted for by the nonspecific or placebo effects of using hypnosis as a method
of treatment; the other may be conceptualized as a distortion of perception specifically
induced during deep hypnosis.
ALTHOUGH dramatic demonstrations of the use of hypnotically induced anesthesia
during major surgery have been reported, 9, 23, 24 controlled experimental studies have
not objectively substantiated its effectiveness.1, 2, 14, 30, 31, 34 A similar paradox exists
concerning the pharmacological effects of analgesic agents. Although opiates, known
since antiquity, are potent analgesic drugs, their effects on pain thresholds have been
difficult to demonstrate experimentally.4,5
Pain as a Complex Experience
Pain usually depends upon the stimulation of specific end-organ receptors. Subjectively,
however, pain intensity does not necessarily reflect the level of stimulation, the extent of
tissue damage, or the danger to the organism. Psychological factors, such as the meaning
From the Unit for Experimental Psychiatry Institute of the Pennsylvania Hospital, and the
Department of Psychiatry, University of Pennsylvania, Philadelphia.
Supported in part by Contract Nonr 4731(00) from the Office of Naval Research.
We wish to thank J. M. Dittborn, C. F Holland, K. Hurson, J. J. Lynch, E. P. Nace, U.
Neisser, D. N. O'Connell, Emily C. Orne, D. A. Paskewitz, C. W. Perry, and P. W.
Sheehan for their helpful comments during the preparation of this report, and Mrs. Mary
Louise Burke and Mrs. JoAnne Withington for their considerable editorial assistance.
Received for publication Dec 16, 1968; revision received March 19, 1969.