Further Research
Hypnotic control of pain: historical perspectives and future prospects.
Chaves JF, Dworkin SF. Indiana University School of Dentistry, Indianapolis. International Journal of Clinical and Experimental Hypnosis 1997 Oct; 45(4):356-76
Hypnotic analgesia has occupied a pivotal place in experimental and clinical hypnosis. It emerged early in the 19th century when effective clinical techniques for pain management had not yet developed, and the relief of pain and suffering had not even become a well-defined social goal. Its acceptance was further complicated by political struggles surrounding the humanitarian transformation of medicine during this era as well as a redefinition of the physician-patient relationship that wrested control from the patient.
The initial struggle for professional acceptance was won only when the debate became almost entirely localized within the professional community. Acceptance of hypnosis by professional organizations has been followed by alternating periods of interest and indifference. While the evidence for the powerful effects of suggestion and related variables has often been observed and reported in nonhypnotic contexts, their relationship to hypnotic phenomena has often not been appreciated.
Since the mid-20th century, scientific information about hypnotic analgesia has grown substantially and has had significant influence on strategies for acute and chronic pain management. If recent calls for its wider application in pain management are to succeed, it will require additional data from clinical populations and a balanced and scientifically prudent approach by its advocates.
Cerebral mechanisms of hypnotic induction and suggestion.
Rainville P, Hofbauer RK, Paus T, Duncan GH, Bushnell MC, Price DD. Universite de Montreal, Montreal, Canada Journal of Cognitive Neuroscience 1999 Jan; 11(1):110-25
The neural mechanisms underlying hypnotic states and responses to hypnotic suggestions remain largely unknown and, to date, have been studied only with indirect methods. Here, the effects of hypnosis and suggestions to alter pain perception were investigated in hypnotizable subjects by using positron emission tomography (PET) measures of regional cerebral blood flow (rCBF) and electro-encephalographic (EEG) measures of brain activity. The experimental conditions included a restful state (Baseline) followed by hypnotic relaxation alone (Hypnosis) and by hypnotic relaxation with suggestions for altered pain unpleasantness (Hypnosis-with-Suggestion).
During each scan, the left hand was immersed in neutral (35 degrees C) or painfully hot (47 degrees C) water in the first two conditions and in painfully hot water in the last condition. Hypnosis was accompanied by significant increased in both occipital rCBF and delta EEG activity, which were highly correlated with each other (r=0.70, P<0.0001). Peak increases in rCBF were also observed in the caudal part of the right anterior cingulate sulcus and bilaterally in the inferior frontal gyri. Hypnosis-related decreases in rCBF were found in the right inferior parietal lobule, the left precuneus, and the posterior cingulate gyrus.
Hypnosis-with-suggestions produced additional widespread increases in rCBF in the frontal cortices predominantly on the left side. Moreover, the medial and lateral posterior parietal cortices showed suggestion-related increases overlapping partly with regions of hypnosis-related decreases.
Results support a state theory of hypnosis in which occipital increases in rCBF and delta activity reflect the alteration of consciousness associated with decreased arousal and possible facilitation of visual imagery. Frontal increases in rCBF associated with suggestions for altered perception might reflect the verbal mediation of the suggestions, working memory, and top-down processes involved in the reinterpretation of the perceptual experience. These results provide a new description of the neurobiological basis of hypnosis, demonstrating specific patterns of cerebral activation associated with the hypnotic state and with the processing of hypnotic suggestions.
