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ACUPUNCTURE, TOUCH, AND THE PLACEBO RESPONSE
Anthony Campbell
Reprinted from Acupuncture, touch, and the placebo response;
8(1):43-46, March 2000, Complementary Therapies in Medicine, by
permission of the publisher
Churchill Livingstone. Users may not print out or otherwise reproduce
copies of the material without the written permission of the copyright
holder
Acupuncture practitioners who subscribe to the modern or non-traditional
version of the therapy maintain that what they do is scientific, in the
sense that it is founded on what mainstream science knows about the
nervous system and other physiological systems[1]. Moreover, they can
point to a modest but not insignificant body of research to support
their claim, and there are plausible physiological mechanisms that may
explain at least some of the observed phenomena[2]. And yet, if you talk
to such practitioners, you quickly get the impression that they regard
what they do as an art as well as a science. This is true of all of
medicine, of course, but it is especially true of manual techniques such
as acupuncture; most practitioners think that the skill with which the
treatment is applied makes a lot of difference to the outcome.
Admittedly there are a few who don't share this attitude. A consultant
neurologist who used acupuncture told me that he found the actual
needling of patients boring and therefore deputed it to
physiotherapists. However, this view is not widely held. Indeed, quite a
number of acupuncturists, not necessarily adherents of the traditional
system, can be induced to admit that they feel as if "something" were
being transmitted via the needle to the patient, although they generally
disavow, in the next breath, any suggestion of a mysterious or
paranormal "life force". It is the nature of this "something" that I
want to explore. My hope is that this can be done without plunging us
into irrationality. The clue, I suggest, is to be found in the quality
of touch.
Touch as a form of therapy
Touch is a form of communication, which differs from spoken language in
that it is "primitive" and pre-verbal and can produce a sense of
reassurance and calm in a patient. There are good reasons based in our
evolutionary history why this should be the case: grooming is a standard
method of social communication for our simian relatives and the rarity
with which most humans indulge in it, outside a sexual or a mother-baby
context, is probably an aberration from an evolutionary standpoint.
Conventional doctors do touch their patients in the course of a physical
examination but the ostensible function of the procedure is diagnostic,
although even here there may be an element of reassurance and acceptance
that has some therapeutic value. The psychological importance of touch
is more obvious in the case of the manual therapies, in which diagnosis
and treatment tend to overlap and begin to
blend into each other.
In the case of acupuncture, for example, it is natural to focus on the
needles as the central thing. But acupuncture generally also entails a
more or less comprehensive preliminary physical examination, which in
the traditional system includes palpation of the pulses and in the
modern version is likely to include manual palpation of the spine and
other areas for trigger points (TPs)[3]. I believe that this tactile
component, though it is primarily regarded as a diagnostic procedure,
may at times also have therapeutic effects independently of the needles.
One reason for this is that the manual pressure used for detection may
also inactivate the TPs when found, at least temporarily, by means of
so-called "acupressure". And even if this does not happen, the process
of examination is probably perceived unconsciously by the patient (and
perhaps the acupuncturist) as therapeutic. Pressing the trapezius
muscles to search for TPs is quite similar to giving a therapeutic
massage; indeed, many patients may have asked a spouse or other relative
to massage their shoulders in this way to relieve tension. The same
applies to pressure designed to elicit tenderness in other parts of the
body; this recalls the practice, widespread in Asian countries, of
asking a relative to walk on one's body with bare feet in order to
relieve pain.
There is probably a degree of touch-induced healing involved in every
successful episode of manual therapy, including acupuncture. This is the
theme of an important recent book by Bevis Nathan, an osteopath[4].
We may say that this or that technique is a local-tissue
technique only and devoid of meaning, and we may have reasonable
arguments upon which this statement rests. Nevertheless a
patient may experience our touch (consciously or unconsciously)
emotionally, whatever we may say... a positive experience of a
practitioner's touch will induce feelings of improved
self-image, increased self-worth and well-being. This will occur
where touch is caring, sensitive, confident, competent and
respectful, and is accompanied by requests for permission to
perform techniques. These positive feelings will generate and
reinforce the patient's belief that healing is taking place.
This, in turn, will generate bodily physiological healing
events. (p.125).
Conversely, of course, a practitioner whose touch is not caring,
sensitive, and so forth will not generate these desirable effects. This
may well be part of the reason why certain acupuncturists seem to obtain
consistently better results than others.
The case of self-acupuncture is interesting in this context. Patients
are sometimes taught to carry out their own acupuncture and this
generally works quite well. However, it is not unusual for them to say
that their own efforts are less successful than those of the therapist,
and they may ask for an occasional "booster" to maintain the
improvement. Such patients are usually doing the acupuncture perfectly
well from a technical point of view, and therefore it seems that there
is something extra that is being contributed by the therapist.
We could summarize all this by saying that success in acupuncture may
not be wholly due to the needles but may also depend on messages
transmitted and received, largely unconsciously, via the acupuncturist's
hands during the preliminary diagnostic examination. The fact that
touch appears to work at a more basic or primitive level than does
verbal suggestion would explain why patients' prior beliefs in
acupuncture seem to make no difference to the clinical outcome[5].
Verbal interaction no doubt plays a part, but is possibly less
important than the touch component. Both patient and therapist will
attribute all, or nearly all, the symptomatic relief to the needles,
perhaps with the addition of a degree of "suggestion", but this may not
be the whole story.
To put it differently, probably almost every successful episode of
manual therapy is also, to some extent, an episode of psychotherapy. The
reverse is also true: psychotherapy is likely to have effects on the
body. It might therefore seem rational to use touch as part of
psychotherapy, but this practice is almost entirely taboo in
conventional psychotherapy, no doubt for understandable reasons. In
recent years, however, there have been some attempts to overcome this
barrier; the subject is well discussed, with references, by Nathan (pp.
133-193)[4].
Does this mean that acupuncture is "just placebo"?
At this point, if not before, scientifically minded acupuncturists are
likely to feel uncomfortable, for we seem to be coming perilously near
to conceding the critics' case that acupuncture is nothing more than a
superior placebo. This is in fact still a possibility, as Ernst and
White have pointed out (p. 156)[6]. And what makes the critics' charge
even more telling is the fact that although there is a fair amount of
scientific evidence to show that acupuncture in the broad sense has
some effect, there is very little to show that any one method of doing
it is better than another. It is difficult to argue convincingly that
traditional acupuncture is better than modern acupuncture or vice versa,
or that one version of modern acupuncture is better than another.
Unanswered quite basic questions abound. Should the needles be left in
for half a minute or twenty minutes? Should the needle be placed
accurately in the trigger point or is superficial needling over the
site enough[3]? Is manual stimulation necessary? Is electrical
stimulation more or less effective than manual stimulation? Do classic
acupuncture points have any real existence or special properties? Not
much reliable guidance is to be found in the research literature on
these or a host of other practical questions. (Incidentally, the same is
true of many other kinds of unorthodox medicine, such as homeopathy,
which also exist in a number of allotropic forms.) But if they all work
to much the same extent, is it possible that none of them really works
at all?
There seem to be two main strategies that might be adopted by therapists
who wish to refute the charge that what they offer is "mere placebo".
The first is to take refuge in mysticism, and the second is to admit
that much of the effect may indeed be due to non-specific influences but
to question the generally received understanding of placebo. I shall
look at each of these in turn.
The mystical alternative
As Nathan points out, the mainstream manipulative professions have
sought to gain acceptance from orthodox medicine by explaining their
procedures in mechanical and physiological terms. The same is true of
modern, non-traditional, acupuncture. However, the founders of
osteopathy and chiropractic, Andrew Still and Daniel Palmer
respectively, were vitalists, as is a minority of their followers even
today. There are also several less conventional schools of manual
therapy that are explicitly vitalistic. Among the manual therapies that
are based on ideas of this kind are shiatsu, therapeutic touch, polarity
therapy, and the various schools of "laying on of hands". Traditional
Chinese acupuncture is expressly vitalistic, depending as it does on the
concepts of yin-yang polarity and chi.
The modern theories underlying such treatments often make mention of
"energy fields", a metaphor derived from physics, but the origins of
these ideas are much older. Nathan connects them, I am sure correctly,
with mystical teachings such as those that were elaborated in great
detail by the Neoplatonists in Alexandria in the early centuries of the
Christian era, although it would be a monumental undertaking to trace
the routes by which these ideas have descended to their present form in
unconventional medicine. A more immediate source can be found in the
work of Wilhelm Reich. He was an associate of Freud and worked with him
in Vienna after the First World War. Like Freud, he was much preoccupied
with sex and placed the attainment of satisfactory orgasm at the root of
his therapeutic theory. Later in life he went to the USA, where he
developed what sounds like a complex delusional system concerned with
"orgone", a kind of cosmic energy. This brought him into conflict with
the US Food and Drug Administration and eventually he was committed to
prison, where he died. Some of Reich's ideas were developed by others,
notably Alexander Lowen, and gave rise to a system of therapy called
Bioenergetics. Other offshoots include Biodynamic therapy and
Biosynthesis.
Nathan is prepared to regard "energetics, field theory, subtle-body
theory, spirituality and even theosophy" as ideas that deserve to be
researched and taken seriously, because they offer "the only possibility
for a comprehensive understanding of human life - one that explicitly
allows for the wealth of history of human experience". I can't follow
him in this. It seems to me that to allow oneself to be involved in
these murky areas is to risk submerging beyond hope of rescue in a sea
of confusion. I prefer to think that we will ultimately be able to offer
an explanation of the psychological and emotional effects of the manual
therapies in neurophysiological terms, though this will entail a
considerably better understanding of the way placebos work than we have
at present.
Don't be frightened of the placebo
The placebo concept still requires a lot of elucidation[7], and indeed
may not be easily applicable to the manual therapies, but meanwhile we
should at least remember that the "placebo effect" is a
neurophysiological phenomenon. This may seem obvious when one thinks
about it, but it is often forgotten. As I have argued elsewhere, there
seems to be an unwarranted assumption on the part of many doctors that
placebo effects are somehow unreal and not very reputable[8]. They
think in this way because they are unconsciously using a dualistic model
of the organism. They say, in effect, that there is the body, which is a
physiological system on which drugs and other medical treatments are
supposed to operate, and there is the mind, which can be affected by
suggestion to produce a spurious effect. Between the mind and the body
there is an ill-defined no-man's land rather inadequately occupied by
something called psychosomatic medicine. Doubtless few would admit to
holding a crude view of this kind, yet this is what seems to be implied
in the pronouncements of some medical critics of complementary medicine.
What is odd about it is that it is incompatible with the materialism
which otherwise characterizes most medical thinking, even (or perhaps
especially) in psychiatry. As a recent Lancet leading article remarked:
"With a few dissenters, psychiatry accepts that in principle its
disorders are disorders of the brain that can and should be investigated
as such."[9]. Exactly the same applies to the placebo phenomenon: it is
produced by the brain and should be approached from that direction.
There is good scientific evidence available to show that the endogenous
opioids are mediators of placebo analgesia although this may not be the
whole explanation, especially in view of the wide variations in what
constitutes a placebo[10]. We are not yet able to specify in any detail
which brain areas and mechanisms are important in relation to the
subjective phenomena that occur in patients receiving manual treatments.
I have elsewhere proposed that the limbic
system may be involved in the production of emotional phenomena such as
euphoria, laughter, and crying in acupuncture patients[11]. Should this
idea turn out to be even partially correct, there is no reason to think
that acupuncture would be the only treatment that is capable of
modifying the activity of the system. Other manipulative methods, such
as those used in physiotherapy, osteopathy, and chiropractic might act
in the same way, and so too might less conventional therapies, all of
which can on occasion give rise to emotional abreactions. There are
numerous descriptions by patients of emotionally charged experiences
while receiving such treatments, especially the more vigorous, such as
Rolfing. The limbic system might thus represent a final common path
(though probably not the only one) by which such treatments work. The
touching that is entailed in examining a patient for TPs would then be
simply one more means of accessing the limbic system. To ask whether
this is a placebo effect seems to be almost meaningless in this
context.
Nathan also favours the limbic system as the part of the brain that is
likely to be involved in psychophysical phenomena of this kind, for he
postulates that a state of chronic hyperarousal in the anterior
cingulate cortex (part of the limbic system) results in a "chronic but
incoherent efferent discharge into the soma... which not only explains
chronic muscular hypertonia, but also provides a baseline explanation
for all psychosomatic pathology"(p. 188)[4].
Conclusions
What I have suggested in this paper is that touch is important in manual
therapies, including acupuncture, but its effects depend on the brain
and are conditioned by a very wide range of influences, not all of which
are easy to identify or delineate. In the case of acupuncture, we need
to consider not only the patient's reactions to the insertion of the
needle but also the effects of the manual examination. There seems no
good reason to be alarmed or defensive about admitting the importance of
this for the final therapeutic outcome.
This analysis seems to offer plenty of scope for the quite widespread
impression among acupuncturists that there is "something else" involved
besides the effects of the needle. That "something else" may indeed
prove to be what is often called the placebo effect, but this should be
understood to be a neurophysiological phenomenon and hence as "real" as
anything else.
On a practical level, this has important implications for how
practitioners of modern medical acupuncture think about what they are
doing. Ernst and White suggest that if it turns out that sham
acupuncture is as effective as "real" acupuncture, research should
concentrate on how to maximize the placebo effect and therapists should
be trained in placebo acupuncture (p. 156)[6]. However, this seems to
pose a problem for modern therapists, for whom the placebo effect still
retains a certain element of charlatanry. Would it be ethical to deceive
patients (in effect), even if it were for their own good? And, if not,
would telling the patient that this was a placebo procedure negate its
effectiveness? There seem to be serious problems in the deliberate use
of placebo today, though the practice was widespread in medicine before
the Second World War[10].
Perhaps, therefore, we should consider abandoning the use of the word
"placebo" in this context. If we could establish some of the mechanisms
that underlie the subjective phenomena produced by manual treatments, we
might be able to offer a description that avoids the dreaded word
"placebo" in favour of one that was both more accurate and more
acceptable to both patients and therapists. We might, for example, find
ourselves able to say something like this:
Our therapy is designed to help your brain to reprogram itself
in a more healthy way. It takes advantage of the inbuilt healing
propensities of the body, so rather than manipulating the body
from outside we are working with the mechanisms that exist and
encouraging them to take over and restore health.
This would be more than a verbal sleight of hand. It would not be simply
a matter of relinquishing the "placebo" terminology; rather, it would
direct the attention of scientists towards the subjective phenomena, in
the hope that research on these could be integrated with research on the
local tissue phenomena which at present are the main focus of scientific
interest. Admittedly, these subjective phenomena are more difficult to
research, which is one reason why they have been relatively neglected,
but there seems to be no good reason why they should not be integrated
into our general theoretical framework.
References
- Campbell A. A doctor's view of acupuncture: traditional Chinese
theories are unnecessary. Complementary Therapies in Medicine
1998;6:152-155.
- White A, Neurophysiology of acupuncture analgesia. In: Ernst E,
White A (eds) Acupuncture: a scientific appraisal. Lnodn,
Butterworth-Heinemann, 1999.
- Baldry PE. "Acupuncture, Trigger Points and Musculoskeletal Pain'.
Edinburgh: Churchill Livingstone, 1998.
- Nathan B. "Touch and emotion in manual therapy'. Edinburgh:
Churchill Livingstone, 1999.
- Collier S, Phillips D, Camp V, Kirk A. The influence of attitudes to
acupuncture on the outcome of treatment. Acupuncture in Medicine
1995;13:74-77.
- Ernst E, White A. "Acupuncture: a scientific appraisal'. London:
Butterworth-Heinemann, 1999.
- ter Riet G, de Craen AJM, Kessels AGH. Is placebo analgesia mediated
by endogenous opioids? A systematic review. Pain 1998;76:272-275.
- Campbell A. Cartesian dualism and the concept of medical
placebos. Journal of Consciousness Studies 1994;1:230-233.
- Anon Editorial. Lancet 1994;343:681-682.
- Kaptchuk TJ. Powerful placebo: the dark side of the randomized
controlled trial. Lancet 1994l351:722-725.
- Campbell A. The limbic system and emotion in relation to
acupuncture. Acupuncture in Medicine 1999;17:124-130.
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