Hypnosis: Placebo or Nonplacebo? R I C H A R D V A N D Y C K , M.D., PH.D.* K E E S H O O G D U I N , M . D . , PH.D.f
Amsterdam, The Netherlands Nijmegen, The Netherlands
A review of the literature shows that placebo effects are not related to hypnotizability. Clinical outcome studies make it clear that results of hypnotherapy are related to hypnotizability in the treatment of anxiety, pain, and psychophysiological disorders, but not in the treatment of addiction or habit disorders. Finally a procedure is given in which hypnosis is usefully applied for its placebo value as a method to generate positive expectancies. 1. INTRODUCTION During the period preceding World W a r I I , hypnosis was used by the Dutch psychiatrist Stokvis for the treatment of soldiers who had become psychiatrically unfit for military service. With this therapy he had acquired a certain fame among the military. F o r practical reasons he carried out these treatment sessions in a room bearing the inscription "medical psychological laboratory," which contained a Faraday cage and several measuring instruments for psychophysiological experimentation. Mere sight of this set-up apparently made a deep impression, and Stokvis reports that for some patients it was enough to invite them to lie down on the couch in order to develop a deep "hypnotic sleep." M a n y therapists who use hypnosis will have experienced similar examples of strong patient expectancy capable of initiating a therapeutic process with minimal or no intervention from the therapist. 1
In psychotherapy research, effects that are obtained through expectancy rather than through a specified technique, are generally defined as placebo effects. It would seem consistent with this view to consider the immediate trances that Stokvis reported as examples of the power of placebo factors rather than the results of hypnosis. T h e literature offers other examples where expectancy rather than hypnosis seems the more applicable explanation. Stanton treated 20 patients with anxiety by a hand-levitation induction and kept silent for the remaining 20 minutes of the session. After repeating this procedure four times, participants reported on a questionnaire measuring anxiety significant reductions while waiting-list controls did not. L a z a r u s offered all patients requesting hypnosis an identical 2
3
* Professor of Psychiatry, Free University of Amsterdam. fProfessor of Psychopathology, University of Nijmegen. Mailing address: Department of Psychiatry, Reinier de Graaf Gasthuis, Postbus 5012, 2600 G A Delft, The Netherlands. A M E R I C A N J O U R N A L O F PSYCHOTHERAPY, Vol. X L I V , No. 3, July 1990
396
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Nonplacebo?
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nonhypnotic behavior therapy. H a l f of the patients were told that they were treated with hypnosis, while the other half were informed that hypnosis would not be used for them. T h e patients who were led to believe that they were hypnotized reported a slightly better outcome than the others. Not too much should be made of this finding, however, since Lazarus himself was the rater, therapist, and researcher in this study. According to some authors the essence of hypnosis resides in its value as a ceremony for activating therapeutic expectancies. T h i s amounts to a view in which hypnosis is considered to be a placebo. T h e concept of placebo, however, is often vaguely defined and inconsistently used. I n recent years the definition of placebo has been discussed extensively by G r u n b a u m . T h e main purpose of this paper will be to examine the evidence for the view that hypnosis is a placebo in the light of Griinbaum's reconceptualization. 4
5,6
2. DEFINITIONS 7
For hypnosis Orne's definition will be used. It states that hypnosis is "that state or condition in which subjects are able to respond to appropriate suggestions with distortions of perception or memory." Essential elements in this definition are the responsivity to suggestions and the ability to distort perception or memory. T h e definition of placebo that was most currently used until recently can be found in an authoritative chapter on placebo in medicine and psychotherapy by Shapiro and Morris. They defined placebo as "any therapy or component of therapy that is deliberately used for its non-specific, psychological or psychophysiological effect, or that is used for its presumed specific effect, but is without specific effect for the condition being treated." I f one looks closely at this definition, it is clear that psychological interventions are by necessity of a placebo nature. Furthermore a definition by exclusion is always a weakness. Shapiro and Morris's definition was also criticized by Grunbaum ' because of the use of the term "specific" as synonymous for nonplacebo and "nonspecific" as interchangeable for placebo. Since placebo effects can very well be measured and specified, the term nonspecific obscures rather than clarifies the issue. Furthermore, the qualification of "specific" therapy has already received another meaning from Rosenthal and F r a n k . These authors defined a "specific" therapy as one which was proven to be more effective than a placebo with the same credibility. Obviously, this is a more stringent requirement than simply being effective. As a matter of fact, a widely used procedure with demonstrated effectiveness such as Systematic Desensitization appears not to be able to meet this criterium. 8
5
6
9
10
5
6
In his two thoughtful essays, Grunbaum ' offered an alternative definition for placebo that avoided the pitfalls previously discussed. H e maintained that the decision whether or not a therapy is a placebo, should be related to a disease and to a theory about the (characteristic) effects of the therapy on that disease. I n a somewhat abbreviated form, Griinbaum's definition held that a therapy was a
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nonplacebo if it could be objectively demonstrated that its effect on a disease depended on its characteristic factors; i.e., if it operated according to the theory that described its activity. I f a treatment has an effect that does not depend on the characteristic factors, but on other elements, for which Griinbaum introduces the term "incidental" factors, then the therapy should be called a placebo for this disease. Grunbaum's definition calls for process rather than outcome studies in order to empirically demonstrate the nonplacebo nature of a treatment. If we wish to adopt his definition for the purpose of exploring whether or not hypnosis is a placebo, we must state a theory that predicts in which way hypnosis will promote therapeutic results. It is one of the merits of Grunbaum's approach that specific statements are required in a field that traditionally abounds in vagueness. T h e most widely accepted theory about hypnotherapy holds that therapeutic effects are obtained through the activation and employment of the ability to distort memory or perception, which was referred to in Orne's definition. I n Grunbaum's terminology, activation of this talent would be the characteristic factor of a therapy with hypnosis. Most practitioners and researchers believe that this talent is measurable. Setting aside discussions about the optimal instrument for measuring this ability, it is assumed that several scales more or less imperfectly represent the hypnotizability of a patient. T h e theory predicts that therapeutic outcome should be related to the hypnotizability score if hypnosis is to be credited for the therapeutic result. Otherwise, not the "characteristic," but an "incidental" element of the procedure should be held responsible for the outcome, and hypnosis would be a placebo. 7
There is an alternative view, which essentially states that hypnosis is a procedure to raise therapeutic expectancy, while placing little emphasis on the role of hypnotizability. T h i s view builds on Jerome F r a n k ' s work on general factors in psychotherapy. A related but somewhat different view is derived from the work of Milton H . Erickson. It is less clearly elaborated, but essentially states that measured hypnotizability is not a critical element, but therapeutic success depends entirely upon the flexibility that the therapist demonstrates in meeting widely varying patient needs. ' While no research is as yet available in which this characteristic of successfully meeting patients' needs has been operationalized and measured, this view should be kept in mind as an alternative to the explanation based on hypnotizability. However, these alternative views would need amendment if hypnotizability were shown to be a characteristic factor in hypnotherapy. 11
12
13
14
3. LABORATORY STUDIES Data for examining the relation between hypnosis and placebo come from several sources. E v a n s reviewed seven studies in which placebo pills were administered for varying complaints to patients who were tested for suggestibility. T h i s testing was usually done with a simple procedure such as the body sway 15
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test. T h e correlation between such tests and hypnotizability scores varies be16
tween .38 and .70. '
17
Only one of the seven studies reviewed showed a
significant correlation between the effect of the placebo and the suggestibility test. 1 8
T o Evans's review should be added a study by Bentler et a l . who employed a more elaborate hypnotizability score; these authors also failed to find a relation between hypnotizability and the analgesic effect of a placebo pill. I n summary, as far as placebo pills are concerned, hypnosis or hypnotizability do not appear to offer an adequate explanation of their effectiveness. Another piece of evidence that makes it improbable that placebo effects should be considered as related to hypnosis is the finding that the placebo reactivity appears to be variable. I n other words, positive reaction to a placebo does not predict the future reactions of that person.
19,20
Conversely, placebo reactivity
seems to be a state rather than a trait variable. Hypnotizability is documented as being a rather stable trait,
21
which makes it unlikely that the same processes are
operating in both hypnosis and placebo effects. T h e evidence reviewed so far is of an indirect nature: it fails to support the notion that placebo effects should be explained by hypnotizability. Only one direct comparison between hypnosis and a placebo pill is available in the research literature. It is the carefully designed but complex study by McGlashan et a l .
22
In this study, subjects with high and low hypnotizability were compared on the analgesic effects of a placebo pill versus hypnosis. Special precautions were taken to ensure that the pills were administrated as if they were effective analgesics and people with low hypnotizability were ingeniously led to believe that hypnosis had an effect on them. T h e outcome of this experiment was that they experienced a comparable amount of pain reduction under both conditions. Conversely, subjects with high hypnotizability showed a far greater pain reduction with hypnosis than with the placebo. T h i s study has recently been partially replicated and expanded by Stam and Spanos.
23
Instead of a placebo pill, these authors used a bogus apparatus. It was
designed to control for order effects as both placebo followed by hypnosis and hypnosis followed by placebo were tested. When placebo preceded hypnosis, Stam and Spanos found significantly more pain reduction in highly hypnotizable subjects, as had McGlashan et al. in their study. However, no such difference was found when hypnosis preceded placebo. T h i s appears to be due to the fact that highly hypnotizable subjects performed much better with placebo. As the authors point out, it is possible that these subjects still used the cognitive strategies of the hypnotic analgesia, as both conditions followed each other closely in time. In our opinion the results of their study essentially confirm the findings of McGlashan et al. rather than invalidate them, as Stam and Spanos seem to imply. These data once more illustrate the variable nature of placebo reactions. T h e findings so far reviewed are very compatible with a two-factor model of hypnotic analgesia,
24
that would consist of a weaker general effect found in
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subjects with high and subjects with low hypnotizability; and a stronger effect only found in those with high hypnotizability. 4.
CLINICAL STUDIES
T h e above data pertain to laboratory experiments with volunteers and not with clinical patients. They may not be predictive of processes encountered in clinical practice. Research in which hypnosis is compared to a placebo procedure in actual patients is not available. A considerable number of studies contain data on the contribution of hypnotizability to outcome of hypnotherapy for several disorders. These studies have been independently discussed in two reviews. ' T h e general picture emerging from these clinical studies is that therapeutic outcome is consistently related to hypnotizability in the treatment of anxiety, pain, and psychophysiological disorders, while it is unrelated in the treatment of habit and addiction problems. I n Griinbaum's terminology this would make hypnosis a placebo for behavioral and habit disorders but a nonplacebo for treatment of pain, anxiety, and some psychophysiological disorders such as asthma. 25
26
However, if one looks at the size of these correlations, the result is often not very impressive. For example, in a study with agoraphobics, V a n D y c k found that hypnotizability contributed between 6 and 19% to the variance of different outcome measures. T h i s means that at least 80% of the variance derives from sources other than the "characteristic" factor of this therapy. 10
A n intriguing finding is that hypnotizability may be predictive of the outcome of psychiatric therapy, even when no hypnosis is used in the treatment. I n the study with agoraphobics mentioned above, hypnotizability contributed between 0 and 6% of the variance to outcome measures in a condition without hypnosis. If this finding proved to be consistent, hypnotizability should—in addition to being a characteristic element of hypnotherapy—be considered as a (weak) general predictor of "treatability," perhaps through therapeutic compliance. 27
10
5. RATIONAL USE OF HYPNOSIS AS A PLACEBO: AN EXAMPLE It obviously makes sense to use hypnosis if a characteristic or nonplacebo effect can be expected. However, hypnosis can also be applied rationally and to the patient's advantage when no relation to hypnotizability is demonstrated, e.g., in the treatment of undesirable behaviors or habits, as is illustrated in the following procedure designed to help people to stop smoking. After several failed attempts to stop smoking, patients usually have become convinced that they are not capable of solving their problem without professional help. Articles in the popular press may have strengthened the belief that hypnosis has something special to offer; in its extreme form, people may expect to go into a deep sleep and wake up as nonsmokers. T h e therapist's suggestion for another approach may be experienced as a rejection. It is, therefore, often advisable to support rather than disregard or denigrate the patient's beliefs and expectations. 28
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A strategy that can be used is to postpone the actual hypnosis induction until extensive "preliminary" arrangements have been made.
These consist of a
self-control program such as monitoring, self-reinforcement, and response cost, which have proved to be valuable in habit and addiction control. Let us assume that the patient has requested treatment by hypnosis. During the session it is discussed that hypnosis will be induced at the end of the hour. T h e chance that there will be resistance to these arrangements is minimized because of the patient's belief that treatment will really begin at the moment hypnosis begins. Therefore, the patient may be even more susceptible to suggestions such as the following: "There are patients who, once having begun treatment by means of hypnotherapy, notice that they become very sensitive to the hot, burning feeling in the throat caused by smoking," or, "Some patients notice that they sense a kind of distaste when they think of cigarettes and get a satisfied, pleasant feeling when they haven't smoked for a while. O r they immediately notice a sense of irritation when they light a cigarette and this makes them decide to stub it out."
T h e therapist can also express surprise at the effect that
hypnotherapy sometimes has, namely, that even confirmed smokers suddenly decide to give up. T h i s effect is then ascribed to the strong, unconscious, inner distaste for their habit.
29
When the trance induction finally begins, the behavioural treatment has already been provided. A registration assignment has been given, a self-control program has been designed and the indirect suggestions made. T h e trance induction then takes place in accordance with the patient's expectations. T h e method used is usually eye fixation. T h e induction is carried out to assure success. When introducing the trance it can be mentioned that some people do not enter into a deep trance the first time, that sometimes they achieve only a slightly relaxed state, but that that in itself is enough. Also, it is advisable to give the patient some information about the feeling of "being aware" during hypnosis, because many people have been led to believe that hypnosis induces a kind of deep sleep during which a cure is achieved. Preparation for this method is made during the preinduction talk: "It may be that, on fixation, your eyes will start to blink, feel heavy, and then close; it may also be that you will feel a strong desire to close your eyes." When the patient has entered into a trance, the various self-control instructions are repeated, together with the suggestion that the patient will feel a growing desire and capacity to execute the program and successfully rid h i m / herself of the smoking habit. Rather than being directed at the smoking behavior itself, the hypnotic element is aimed at strengthening motivation and positive expectations, while self-control procedures are relied upon to achieve the habit reversal. It remains to be demonstrated empirically that this is the process, actually occurring during "hypnotic self-control" for smoking cessation.
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6. CONCLUDING REMARKS In summary, the available evidence seems to be in support of the idea that, at least for some clinical disorders, hypnosis can be considered a nonplacebo. T h i s may
sound as something like an admission ticket to the League of Proper
Therapies or some other respectable body. However, Griinbaum's definition of a nonplacebo does not imply that we are dealing with a particularly effective treatment; the definition only requires that some elements in the way hypnosis operates are documented. As far as effectiveness is concerned, hypnotic techniques do not tend to be superior to comparable behavioral therapeutic interventions.
30
Conversely, some of the psychotherapeutic interventions of
proven efficacy, such as exposure in vivo for agoraphobia or cognitive therapy for depression, still lack an adequately documented explanation for their way of operating. So, the status of nonplacebo implies only a limited promotion. T h e conclusion that hypnosis is sometimes a nonplacebo should not make one forget that most of its effectiveness is probably derived from factors other than hypnotizability. Among these may be the principles that were mentioned earlier as part of the Ericksonian approach, or elements such as those pointed out by 12
erome F r a n k : the awareness of having been hypnotized supports the conviction that an effective therapy has been dispensed, which is the basis of the previously presented "hypnotic" treatment for smokers. T h i s principle has been 31
empirically demonstrated by Goldstein : she found that patients treated with hypnosis for overweight did slightly better when a hand-levitation induction was used rather than the more common relaxation induction. Since hand levitation by itself is not likely to cure obesity, it is probably the unusual sensation of a floating hand that convinced patients that they were truly hypnotized, which led to a better outcome. As of now, this state of affairs can best be accounted for in a provisional two-factor theory of hypnosis, consisting of hypnotizability as the first characteristic factor and a number of expectancy-related variables as the second, as yet less documented, factor. Depending upon the type of complaint that hypnosis is used for, relaxation may also be an important contributor to outcome. For example, it was found in a study on tension headache patients that in the short run, results of an hypnotic treatment were best predicted by hypnotizability, while in the long run subjective ratings for degree of relaxation proved to be more important. A final possibility that derives from the examination of the status of hypnosis in the light of Griinbaum's new definition of placebo is that hypnosis may have an interesting part to play in further psychotherapy research in the function of "credible placebo." I n psychotherapy research it is often problematic to develop a credible placebo if one wishes to make this comparison with a presumably more effective therapy. By offering hypnosis to unhypnotizable patients, provided they see it as a credible therapy, this requirement may be fulfilled. I n the previously mentioned study with agoraphobics,
10
such a comparison was possible and it
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Placebo or
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demonstrated that exposure in vivo was superior to a placebo in the form of hypnosis given to unhypnotizable phobic patients who had previously rated this treatment as credible. T h i s is to our knowledge the first time that the strict requirement for a "specific" psychotherapy as formulated by Rosenthal and F r a n k has been met. 9
SUMMARY According to Griinbaum's definition of placebo, a therapeutic procedure can be considered a nonplacebo if it can be demonstrated that its effects are produced according to the theory upon which the therapy is based. I f the theory is adopted that hypnotic effects depend upon mobilization of the patient's hypnotizability, which is a measurable characteristic, a testable theory is provided. Experimental literature is reviewed that shows that placebo effects are not related to hypnotizability. Clinical outcome studies make it clear that results of hypnotherapy are related to hypnotizability in some disorders such as pain and anxiety, but not in the treatment of addiction or habit disorders. A n example of a procedure is given in which hypnosis is nonetheless usefully applied for its placebo value as a method to generate positive expectancies. REFERENCES 1. Stokvis, B. Hypnose in de geneeskundige praktijk (Hypnosis in Medical Practice), 2nded. De tijdstroom, Lochem, 1953. 2. Stanton, H . E . The Hypnotic Placebo. In Hypnosis, Burrows, G . D., Collison, D. R., and Dennerstein, L . , Eds. Elsevier, Amsterdam, 1979, pp. 215-21. 3. Lazarus, A. A. "Hypnosis" as a Facilitator in Behavior Therapy. Int. J. Clin. Exp. Hypn., 21:25-31,1973. 4. Stanton, H . E . A Simple Hypnotic Technique to Reduce Anxiety. Aust. J. Clin. Exp. Hypn., 6:35-38,1978. 5. Grunbaum,A. The Placebo Concept. Behav. Res. Ther., 19:157-67, \9S\. 6. Griinbaum, A. The Placebo Concept in Medicine and Psychiatry. Psychol. Med., 16:19-38, 1986. 7. Orne, M . T . On the Construct of Hypnosis: How its Definition Affects Research and Clinical Application. In Handbook of Hypnosis and Psychosomatic Medicine, Burrows, G . D., and Dennerstein, L . , Eds. Elsevier, Amsterdam, 1980, pp 29-49. 8. Shapiro, A. K., and Morris, L . A. The Placebo Effect in Medical and Psychological Therapies. In Handbook of Psychotherapy and Behavior Change, Garfield, S. L . , and Bergin, A. E . , Eds. John Wiley & Sons, New York, 1978, pp 369-410. 9. Rosenthal, D., and Frank, J . D. Psychotherapy and the Placebo-Effect. Psychol. Bull, 53:294-302,1956. 10. Dyck, R. Van. Psychotherapie, Placebo en Suggestie (Psychotherapy, Placebo and Suggestion). University of Leiden, 1986. 11. Frank, J . D. Persuasion and Healing. A Comparative Study of Psychotherapy, (rev. ed.). Johns Hopkins University Press, Baltimore, 1973. 12. Erickson, M . H . Naturalistic Techniques of Hypnosis. Am. J. Clin. Hypn., 1:3-8,1958. 13. Barber, J . Rapid Induction Analgesia: A Clinical Report. Am. J. Clin. Hypn., 19:138-147, 1977.
404 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26.
27. 28.
29.
30. 31.
AMERICAN JOURNAL OF PSYCHOTHERAPY Barber, J . Hypnosis and the Unhypnotizable. Am. J. Clin. Hypn., 23:4-9,1980. E v a n s , F . J . Suggestibility in the Normal Waking State. Psychol. Bull., 67:114-29,1967. Hilgard, E . R. Hypnotic Susceptibility. Harcourt Brace Jovanovich, New York, 1965. Hilgard, E . R. The Stanford Hypnotic Susceptibility Scales as Related to Other Measures of Hypnotic Responsiveness. / . Am. Clin. Hypn., 21:68-83,1978. Bentler, P. M . , O'Hara, J . W., and Krusner, L . Hypnosis and Placebo. Psychol. Rep., 12:153-54,1963. Lasagna, L . , Mosteller, F . , Felsinger, I. von, and Beecker, H . K. A Study of the Placebo Response. Am. J. Med., 16:770,1954. Frank, J . D., Hoehn-Saric, R., Tonber, S. D., et al. Effective Ingredients of Successful Psychotherapy. Brunner/Mazel, New York, 1978. Morgan, A. H . , Johnson, D. C , and Hilgard, E . R. The Stability of Hypnotic Susceptibility. Int. J. Clin. Exp. Hypn., 222:249-57,1974. McGlashan, T . H . , Evans, F . J . , and Orne, M . T . The Nature of Hypnotic Analgesia and Placebo Response to Experimental Pain. Psychosom. Med., 31:227-46,1969. Stam, H . J . , and Spanos, N. P. Hypnotic Analgesia, Placebo Analgesia, and Ischemic Pain: the Effects of Contextual Variables. / . Abnorm. Psychol, 93:313-20,1989. Hilgard, E . R., and Hilgard, J . R. Hypnosis in the Relief of Pain. William Kaufman Inc., California; Los Altos, 1975. Wadden, T . A., and Anderton, C . H . The Clinical Use of Hypnosis. Psychol. Bull, 91:215-53, 1982. Spinhoven, Ph. Het therapeutisch Belang van Hypnotiseerbaarheid (The Therapeutic Importance of Hypnotizability). Kwartaalschrift voor Directieve Therapie en Hypnose, 2:329-65, 1982. Nace, E . P., Warwick, A. M . , Kelley, R. L . , and Evans F . J . Hypnotizability and Outcome in Brief Psychotherapy. / . Clin. Psychiatry, 43:129-33,1982. Hoogduin, C . A. L . Classical Trance Induction in Ericksonian Psychotherapy: Smoking Control. In Ericksonian Psychotherapy, Vol. II., Zeig, J . K . , Ed. Brunner/Mazel, New York, 1985, pp 292-99. Zeig, J . G . Ericksonian Approaches to Promote Abstinence from Cigarette Smoking. In Ericksonian Approaches to Hypnosis and Psychotherapy, Zeig, J . K . , Ed. Brunner/Mazel, New York, 1982. Spinhoven, Ph. Hypnosis and Behavior Therapy: A Review. Int. J. Clin. Exp. Hypn., 35:8-31, 1987. Goldstein, Y . The Effect of Demonstrating to a Subject that She Is in a Hypnotic Trance as a Variable in Hypnotic Interventions with Obese Women. Int. J. Clin. Exp. Hypn., 29:15-23, 1981.
Amsterdam, The Netherlands Nijmegen, The Netherlands
A review of the literature shows that placebo effects are not related to hypnotizability. Clinical outcome studies make it clear that results of hypnotherapy are related to hypnotizability in the treatment of anxiety, pain, and psychophysiological disorders, but not in the treatment of addiction or habit disorders. Finally a procedure is given in which hypnosis is usefully applied for its placebo value as a method to generate positive expectancies. 1. INTRODUCTION During the period preceding World W a r I I , hypnosis was used by the Dutch psychiatrist Stokvis for the treatment of soldiers who had become psychiatrically unfit for military service. With this therapy he had acquired a certain fame among the military. F o r practical reasons he carried out these treatment sessions in a room bearing the inscription "medical psychological laboratory," which contained a Faraday cage and several measuring instruments for psychophysiological experimentation. Mere sight of this set-up apparently made a deep impression, and Stokvis reports that for some patients it was enough to invite them to lie down on the couch in order to develop a deep "hypnotic sleep." M a n y therapists who use hypnosis will have experienced similar examples of strong patient expectancy capable of initiating a therapeutic process with minimal or no intervention from the therapist. 1
In psychotherapy research, effects that are obtained through expectancy rather than through a specified technique, are generally defined as placebo effects. It would seem consistent with this view to consider the immediate trances that Stokvis reported as examples of the power of placebo factors rather than the results of hypnosis. T h e literature offers other examples where expectancy rather than hypnosis seems the more applicable explanation. Stanton treated 20 patients with anxiety by a hand-levitation induction and kept silent for the remaining 20 minutes of the session. After repeating this procedure four times, participants reported on a questionnaire measuring anxiety significant reductions while waiting-list controls did not. L a z a r u s offered all patients requesting hypnosis an identical 2
3
* Professor of Psychiatry, Free University of Amsterdam. fProfessor of Psychopathology, University of Nijmegen. Mailing address: Department of Psychiatry, Reinier de Graaf Gasthuis, Postbus 5012, 2600 G A Delft, The Netherlands. A M E R I C A N J O U R N A L O F PSYCHOTHERAPY, Vol. X L I V , No. 3, July 1990
396
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Placebo or
Nonplacebo?
397
nonhypnotic behavior therapy. H a l f of the patients were told that they were treated with hypnosis, while the other half were informed that hypnosis would not be used for them. T h e patients who were led to believe that they were hypnotized reported a slightly better outcome than the others. Not too much should be made of this finding, however, since Lazarus himself was the rater, therapist, and researcher in this study. According to some authors the essence of hypnosis resides in its value as a ceremony for activating therapeutic expectancies. T h i s amounts to a view in which hypnosis is considered to be a placebo. T h e concept of placebo, however, is often vaguely defined and inconsistently used. I n recent years the definition of placebo has been discussed extensively by G r u n b a u m . T h e main purpose of this paper will be to examine the evidence for the view that hypnosis is a placebo in the light of Griinbaum's reconceptualization. 4
5,6
2. DEFINITIONS 7
For hypnosis Orne's definition will be used. It states that hypnosis is "that state or condition in which subjects are able to respond to appropriate suggestions with distortions of perception or memory." Essential elements in this definition are the responsivity to suggestions and the ability to distort perception or memory. T h e definition of placebo that was most currently used until recently can be found in an authoritative chapter on placebo in medicine and psychotherapy by Shapiro and Morris. They defined placebo as "any therapy or component of therapy that is deliberately used for its non-specific, psychological or psychophysiological effect, or that is used for its presumed specific effect, but is without specific effect for the condition being treated." I f one looks closely at this definition, it is clear that psychological interventions are by necessity of a placebo nature. Furthermore a definition by exclusion is always a weakness. Shapiro and Morris's definition was also criticized by Grunbaum ' because of the use of the term "specific" as synonymous for nonplacebo and "nonspecific" as interchangeable for placebo. Since placebo effects can very well be measured and specified, the term nonspecific obscures rather than clarifies the issue. Furthermore, the qualification of "specific" therapy has already received another meaning from Rosenthal and F r a n k . These authors defined a "specific" therapy as one which was proven to be more effective than a placebo with the same credibility. Obviously, this is a more stringent requirement than simply being effective. As a matter of fact, a widely used procedure with demonstrated effectiveness such as Systematic Desensitization appears not to be able to meet this criterium. 8
5
6
9
10
5
6
In his two thoughtful essays, Grunbaum ' offered an alternative definition for placebo that avoided the pitfalls previously discussed. H e maintained that the decision whether or not a therapy is a placebo, should be related to a disease and to a theory about the (characteristic) effects of the therapy on that disease. I n a somewhat abbreviated form, Griinbaum's definition held that a therapy was a
398
AMERICAN JOURNAL
OF PSYCHOTHERAPY
nonplacebo if it could be objectively demonstrated that its effect on a disease depended on its characteristic factors; i.e., if it operated according to the theory that described its activity. I f a treatment has an effect that does not depend on the characteristic factors, but on other elements, for which Griinbaum introduces the term "incidental" factors, then the therapy should be called a placebo for this disease. Grunbaum's definition calls for process rather than outcome studies in order to empirically demonstrate the nonplacebo nature of a treatment. If we wish to adopt his definition for the purpose of exploring whether or not hypnosis is a placebo, we must state a theory that predicts in which way hypnosis will promote therapeutic results. It is one of the merits of Grunbaum's approach that specific statements are required in a field that traditionally abounds in vagueness. T h e most widely accepted theory about hypnotherapy holds that therapeutic effects are obtained through the activation and employment of the ability to distort memory or perception, which was referred to in Orne's definition. I n Grunbaum's terminology, activation of this talent would be the characteristic factor of a therapy with hypnosis. Most practitioners and researchers believe that this talent is measurable. Setting aside discussions about the optimal instrument for measuring this ability, it is assumed that several scales more or less imperfectly represent the hypnotizability of a patient. T h e theory predicts that therapeutic outcome should be related to the hypnotizability score if hypnosis is to be credited for the therapeutic result. Otherwise, not the "characteristic," but an "incidental" element of the procedure should be held responsible for the outcome, and hypnosis would be a placebo. 7
There is an alternative view, which essentially states that hypnosis is a procedure to raise therapeutic expectancy, while placing little emphasis on the role of hypnotizability. T h i s view builds on Jerome F r a n k ' s work on general factors in psychotherapy. A related but somewhat different view is derived from the work of Milton H . Erickson. It is less clearly elaborated, but essentially states that measured hypnotizability is not a critical element, but therapeutic success depends entirely upon the flexibility that the therapist demonstrates in meeting widely varying patient needs. ' While no research is as yet available in which this characteristic of successfully meeting patients' needs has been operationalized and measured, this view should be kept in mind as an alternative to the explanation based on hypnotizability. However, these alternative views would need amendment if hypnotizability were shown to be a characteristic factor in hypnotherapy. 11
12
13
14
3. LABORATORY STUDIES Data for examining the relation between hypnosis and placebo come from several sources. E v a n s reviewed seven studies in which placebo pills were administered for varying complaints to patients who were tested for suggestibility. T h i s testing was usually done with a simple procedure such as the body sway 15
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test. T h e correlation between such tests and hypnotizability scores varies be16
tween .38 and .70. '
17
Only one of the seven studies reviewed showed a
significant correlation between the effect of the placebo and the suggestibility test. 1 8
T o Evans's review should be added a study by Bentler et a l . who employed a more elaborate hypnotizability score; these authors also failed to find a relation between hypnotizability and the analgesic effect of a placebo pill. I n summary, as far as placebo pills are concerned, hypnosis or hypnotizability do not appear to offer an adequate explanation of their effectiveness. Another piece of evidence that makes it improbable that placebo effects should be considered as related to hypnosis is the finding that the placebo reactivity appears to be variable. I n other words, positive reaction to a placebo does not predict the future reactions of that person.
19,20
Conversely, placebo reactivity
seems to be a state rather than a trait variable. Hypnotizability is documented as being a rather stable trait,
21
which makes it unlikely that the same processes are
operating in both hypnosis and placebo effects. T h e evidence reviewed so far is of an indirect nature: it fails to support the notion that placebo effects should be explained by hypnotizability. Only one direct comparison between hypnosis and a placebo pill is available in the research literature. It is the carefully designed but complex study by McGlashan et a l .
22
In this study, subjects with high and low hypnotizability were compared on the analgesic effects of a placebo pill versus hypnosis. Special precautions were taken to ensure that the pills were administrated as if they were effective analgesics and people with low hypnotizability were ingeniously led to believe that hypnosis had an effect on them. T h e outcome of this experiment was that they experienced a comparable amount of pain reduction under both conditions. Conversely, subjects with high hypnotizability showed a far greater pain reduction with hypnosis than with the placebo. T h i s study has recently been partially replicated and expanded by Stam and Spanos.
23
Instead of a placebo pill, these authors used a bogus apparatus. It was
designed to control for order effects as both placebo followed by hypnosis and hypnosis followed by placebo were tested. When placebo preceded hypnosis, Stam and Spanos found significantly more pain reduction in highly hypnotizable subjects, as had McGlashan et al. in their study. However, no such difference was found when hypnosis preceded placebo. T h i s appears to be due to the fact that highly hypnotizable subjects performed much better with placebo. As the authors point out, it is possible that these subjects still used the cognitive strategies of the hypnotic analgesia, as both conditions followed each other closely in time. In our opinion the results of their study essentially confirm the findings of McGlashan et al. rather than invalidate them, as Stam and Spanos seem to imply. These data once more illustrate the variable nature of placebo reactions. T h e findings so far reviewed are very compatible with a two-factor model of hypnotic analgesia,
24
that would consist of a weaker general effect found in
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subjects with high and subjects with low hypnotizability; and a stronger effect only found in those with high hypnotizability. 4.
CLINICAL STUDIES
T h e above data pertain to laboratory experiments with volunteers and not with clinical patients. They may not be predictive of processes encountered in clinical practice. Research in which hypnosis is compared to a placebo procedure in actual patients is not available. A considerable number of studies contain data on the contribution of hypnotizability to outcome of hypnotherapy for several disorders. These studies have been independently discussed in two reviews. ' T h e general picture emerging from these clinical studies is that therapeutic outcome is consistently related to hypnotizability in the treatment of anxiety, pain, and psychophysiological disorders, while it is unrelated in the treatment of habit and addiction problems. I n Griinbaum's terminology this would make hypnosis a placebo for behavioral and habit disorders but a nonplacebo for treatment of pain, anxiety, and some psychophysiological disorders such as asthma. 25
26
However, if one looks at the size of these correlations, the result is often not very impressive. For example, in a study with agoraphobics, V a n D y c k found that hypnotizability contributed between 6 and 19% to the variance of different outcome measures. T h i s means that at least 80% of the variance derives from sources other than the "characteristic" factor of this therapy. 10
A n intriguing finding is that hypnotizability may be predictive of the outcome of psychiatric therapy, even when no hypnosis is used in the treatment. I n the study with agoraphobics mentioned above, hypnotizability contributed between 0 and 6% of the variance to outcome measures in a condition without hypnosis. If this finding proved to be consistent, hypnotizability should—in addition to being a characteristic element of hypnotherapy—be considered as a (weak) general predictor of "treatability," perhaps through therapeutic compliance. 27
10
5. RATIONAL USE OF HYPNOSIS AS A PLACEBO: AN EXAMPLE It obviously makes sense to use hypnosis if a characteristic or nonplacebo effect can be expected. However, hypnosis can also be applied rationally and to the patient's advantage when no relation to hypnotizability is demonstrated, e.g., in the treatment of undesirable behaviors or habits, as is illustrated in the following procedure designed to help people to stop smoking. After several failed attempts to stop smoking, patients usually have become convinced that they are not capable of solving their problem without professional help. Articles in the popular press may have strengthened the belief that hypnosis has something special to offer; in its extreme form, people may expect to go into a deep sleep and wake up as nonsmokers. T h e therapist's suggestion for another approach may be experienced as a rejection. It is, therefore, often advisable to support rather than disregard or denigrate the patient's beliefs and expectations. 28
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A strategy that can be used is to postpone the actual hypnosis induction until extensive "preliminary" arrangements have been made.
These consist of a
self-control program such as monitoring, self-reinforcement, and response cost, which have proved to be valuable in habit and addiction control. Let us assume that the patient has requested treatment by hypnosis. During the session it is discussed that hypnosis will be induced at the end of the hour. T h e chance that there will be resistance to these arrangements is minimized because of the patient's belief that treatment will really begin at the moment hypnosis begins. Therefore, the patient may be even more susceptible to suggestions such as the following: "There are patients who, once having begun treatment by means of hypnotherapy, notice that they become very sensitive to the hot, burning feeling in the throat caused by smoking," or, "Some patients notice that they sense a kind of distaste when they think of cigarettes and get a satisfied, pleasant feeling when they haven't smoked for a while. O r they immediately notice a sense of irritation when they light a cigarette and this makes them decide to stub it out."
T h e therapist can also express surprise at the effect that
hypnotherapy sometimes has, namely, that even confirmed smokers suddenly decide to give up. T h i s effect is then ascribed to the strong, unconscious, inner distaste for their habit.
29
When the trance induction finally begins, the behavioural treatment has already been provided. A registration assignment has been given, a self-control program has been designed and the indirect suggestions made. T h e trance induction then takes place in accordance with the patient's expectations. T h e method used is usually eye fixation. T h e induction is carried out to assure success. When introducing the trance it can be mentioned that some people do not enter into a deep trance the first time, that sometimes they achieve only a slightly relaxed state, but that that in itself is enough. Also, it is advisable to give the patient some information about the feeling of "being aware" during hypnosis, because many people have been led to believe that hypnosis induces a kind of deep sleep during which a cure is achieved. Preparation for this method is made during the preinduction talk: "It may be that, on fixation, your eyes will start to blink, feel heavy, and then close; it may also be that you will feel a strong desire to close your eyes." When the patient has entered into a trance, the various self-control instructions are repeated, together with the suggestion that the patient will feel a growing desire and capacity to execute the program and successfully rid h i m / herself of the smoking habit. Rather than being directed at the smoking behavior itself, the hypnotic element is aimed at strengthening motivation and positive expectations, while self-control procedures are relied upon to achieve the habit reversal. It remains to be demonstrated empirically that this is the process, actually occurring during "hypnotic self-control" for smoking cessation.
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6. CONCLUDING REMARKS In summary, the available evidence seems to be in support of the idea that, at least for some clinical disorders, hypnosis can be considered a nonplacebo. T h i s may
sound as something like an admission ticket to the League of Proper
Therapies or some other respectable body. However, Griinbaum's definition of a nonplacebo does not imply that we are dealing with a particularly effective treatment; the definition only requires that some elements in the way hypnosis operates are documented. As far as effectiveness is concerned, hypnotic techniques do not tend to be superior to comparable behavioral therapeutic interventions.
30
Conversely, some of the psychotherapeutic interventions of
proven efficacy, such as exposure in vivo for agoraphobia or cognitive therapy for depression, still lack an adequately documented explanation for their way of operating. So, the status of nonplacebo implies only a limited promotion. T h e conclusion that hypnosis is sometimes a nonplacebo should not make one forget that most of its effectiveness is probably derived from factors other than hypnotizability. Among these may be the principles that were mentioned earlier as part of the Ericksonian approach, or elements such as those pointed out by 12
erome F r a n k : the awareness of having been hypnotized supports the conviction that an effective therapy has been dispensed, which is the basis of the previously presented "hypnotic" treatment for smokers. T h i s principle has been 31
empirically demonstrated by Goldstein : she found that patients treated with hypnosis for overweight did slightly better when a hand-levitation induction was used rather than the more common relaxation induction. Since hand levitation by itself is not likely to cure obesity, it is probably the unusual sensation of a floating hand that convinced patients that they were truly hypnotized, which led to a better outcome. As of now, this state of affairs can best be accounted for in a provisional two-factor theory of hypnosis, consisting of hypnotizability as the first characteristic factor and a number of expectancy-related variables as the second, as yet less documented, factor. Depending upon the type of complaint that hypnosis is used for, relaxation may also be an important contributor to outcome. For example, it was found in a study on tension headache patients that in the short run, results of an hypnotic treatment were best predicted by hypnotizability, while in the long run subjective ratings for degree of relaxation proved to be more important. A final possibility that derives from the examination of the status of hypnosis in the light of Griinbaum's new definition of placebo is that hypnosis may have an interesting part to play in further psychotherapy research in the function of "credible placebo." I n psychotherapy research it is often problematic to develop a credible placebo if one wishes to make this comparison with a presumably more effective therapy. By offering hypnosis to unhypnotizable patients, provided they see it as a credible therapy, this requirement may be fulfilled. I n the previously mentioned study with agoraphobics,
10
such a comparison was possible and it
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demonstrated that exposure in vivo was superior to a placebo in the form of hypnosis given to unhypnotizable phobic patients who had previously rated this treatment as credible. T h i s is to our knowledge the first time that the strict requirement for a "specific" psychotherapy as formulated by Rosenthal and F r a n k has been met. 9
SUMMARY According to Griinbaum's definition of placebo, a therapeutic procedure can be considered a nonplacebo if it can be demonstrated that its effects are produced according to the theory upon which the therapy is based. I f the theory is adopted that hypnotic effects depend upon mobilization of the patient's hypnotizability, which is a measurable characteristic, a testable theory is provided. Experimental literature is reviewed that shows that placebo effects are not related to hypnotizability. Clinical outcome studies make it clear that results of hypnotherapy are related to hypnotizability in some disorders such as pain and anxiety, but not in the treatment of addiction or habit disorders. A n example of a procedure is given in which hypnosis is nonetheless usefully applied for its placebo value as a method to generate positive expectancies. REFERENCES 1. Stokvis, B. Hypnose in de geneeskundige praktijk (Hypnosis in Medical Practice), 2nded. De tijdstroom, Lochem, 1953. 2. Stanton, H . E . The Hypnotic Placebo. In Hypnosis, Burrows, G . D., Collison, D. R., and Dennerstein, L . , Eds. Elsevier, Amsterdam, 1979, pp. 215-21. 3. Lazarus, A. A. "Hypnosis" as a Facilitator in Behavior Therapy. Int. J. Clin. Exp. Hypn., 21:25-31,1973. 4. Stanton, H . E . A Simple Hypnotic Technique to Reduce Anxiety. Aust. J. Clin. Exp. Hypn., 6:35-38,1978. 5. Grunbaum,A. The Placebo Concept. Behav. Res. Ther., 19:157-67, \9S\. 6. Griinbaum, A. The Placebo Concept in Medicine and Psychiatry. Psychol. Med., 16:19-38, 1986. 7. Orne, M . T . On the Construct of Hypnosis: How its Definition Affects Research and Clinical Application. In Handbook of Hypnosis and Psychosomatic Medicine, Burrows, G . D., and Dennerstein, L . , Eds. Elsevier, Amsterdam, 1980, pp 29-49. 8. Shapiro, A. K., and Morris, L . A. The Placebo Effect in Medical and Psychological Therapies. In Handbook of Psychotherapy and Behavior Change, Garfield, S. L . , and Bergin, A. E . , Eds. John Wiley & Sons, New York, 1978, pp 369-410. 9. Rosenthal, D., and Frank, J . D. Psychotherapy and the Placebo-Effect. Psychol. Bull, 53:294-302,1956. 10. Dyck, R. Van. Psychotherapie, Placebo en Suggestie (Psychotherapy, Placebo and Suggestion). University of Leiden, 1986. 11. Frank, J . D. Persuasion and Healing. A Comparative Study of Psychotherapy, (rev. ed.). Johns Hopkins University Press, Baltimore, 1973. 12. Erickson, M . H . Naturalistic Techniques of Hypnosis. Am. J. Clin. Hypn., 1:3-8,1958. 13. Barber, J . Rapid Induction Analgesia: A Clinical Report. Am. J. Clin. Hypn., 19:138-147, 1977.
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AMERICAN JOURNAL OF PSYCHOTHERAPY Barber, J . Hypnosis and the Unhypnotizable. Am. J. Clin. Hypn., 23:4-9,1980. E v a n s , F . J . Suggestibility in the Normal Waking State. Psychol. Bull., 67:114-29,1967. Hilgard, E . R. Hypnotic Susceptibility. Harcourt Brace Jovanovich, New York, 1965. Hilgard, E . R. The Stanford Hypnotic Susceptibility Scales as Related to Other Measures of Hypnotic Responsiveness. / . Am. Clin. Hypn., 21:68-83,1978. Bentler, P. M . , O'Hara, J . W., and Krusner, L . Hypnosis and Placebo. Psychol. Rep., 12:153-54,1963. Lasagna, L . , Mosteller, F . , Felsinger, I. von, and Beecker, H . K. A Study of the Placebo Response. Am. J. Med., 16:770,1954. Frank, J . D., Hoehn-Saric, R., Tonber, S. D., et al. Effective Ingredients of Successful Psychotherapy. Brunner/Mazel, New York, 1978. Morgan, A. H . , Johnson, D. C , and Hilgard, E . R. The Stability of Hypnotic Susceptibility. Int. J. Clin. Exp. Hypn., 222:249-57,1974. McGlashan, T . H . , Evans, F . J . , and Orne, M . T . The Nature of Hypnotic Analgesia and Placebo Response to Experimental Pain. Psychosom. Med., 31:227-46,1969. Stam, H . J . , and Spanos, N. P. Hypnotic Analgesia, Placebo Analgesia, and Ischemic Pain: the Effects of Contextual Variables. / . Abnorm. Psychol, 93:313-20,1989. Hilgard, E . R., and Hilgard, J . R. Hypnosis in the Relief of Pain. William Kaufman Inc., California; Los Altos, 1975. Wadden, T . A., and Anderton, C . H . The Clinical Use of Hypnosis. Psychol. Bull, 91:215-53, 1982. Spinhoven, Ph. Het therapeutisch Belang van Hypnotiseerbaarheid (The Therapeutic Importance of Hypnotizability). Kwartaalschrift voor Directieve Therapie en Hypnose, 2:329-65, 1982. Nace, E . P., Warwick, A. M . , Kelley, R. L . , and Evans F . J . Hypnotizability and Outcome in Brief Psychotherapy. / . Clin. Psychiatry, 43:129-33,1982. Hoogduin, C . A. L . Classical Trance Induction in Ericksonian Psychotherapy: Smoking Control. In Ericksonian Psychotherapy, Vol. II., Zeig, J . K . , Ed. Brunner/Mazel, New York, 1985, pp 292-99. Zeig, J . G . Ericksonian Approaches to Promote Abstinence from Cigarette Smoking. In Ericksonian Approaches to Hypnosis and Psychotherapy, Zeig, J . K . , Ed. Brunner/Mazel, New York, 1982. Spinhoven, Ph. Hypnosis and Behavior Therapy: A Review. Int. J. Clin. Exp. Hypn., 35:8-31, 1987. Goldstein, Y . The Effect of Demonstrating to a Subject that She Is in a Hypnotic Trance as a Variable in Hypnotic Interventions with Obese Women. Int. J. Clin. Exp. Hypn., 29:15-23, 1981.
