Paper 1, Week 6, MSc Medical Anthropology
Tutorial on Treatment Evaluation, 18.11.2002
Barbara Gerke
Q: Discuss methods used for evaluating the efficacy of medical treatment, present their
advantages, and explain why they are not entirely satisfactory.
There is no a priori reason to claim that one kind of knowledge
is more authentic or autonomous than the other forms.
ALLAN YOUNG (1981:380)
Introduction
Blind assessment and the use of placebos, which look back to a history of over two hundred
years, developed mainly after World War II into a method used in biomedicine for the
evaluation of medical treatment. This essay will deconstruct briefly the history of placebos in
the context of the development of treatment evaluation, and will highlight the advantages of
randomised clinical trials (RCT). I will also discuss the limits of RCT in terms of doctorpatient relationships and why RCT are not satisfactory when applied to traditional medical
systems, taking the example of Tibetan medicine. Finally, two methods that have been
proposed by scholars (Montellano 1975 and Browner et al 1988) to assess the efficacy of
traditional medicine will be critically evaluated.
1. Deconstructing the History of Placebo
Placebo (lit. “I will please you”) has a been viewed differently at different times in history. A
historical deconstruction of the use of placebo in blind assessments is necessary to understand
the impact it had on the process of marginalising the therapeutic success of placebos as well
as traditional medical treatment methods in favour of a biomedical supremacy.
In order for biomedicine to establish itself as an authoritative medical system in Europe and
North America, it needed a method to “isolate ‘hard’ knowledge and material causality from
the contamination of mental delusion, enthusiastic bias, or even calculated deceit.” (Kaptchuk
1998:391). Only with an unbiased scientific method, biomedicine was able to gain the
financial and political control over medical education and practice. Once the cultural authority
was gained through a “rigorous but open, a thorough but unbiased approach to health and
disease” (Sullivan 1993:217), biomedicine could claim to be the most successful and only
valid medicine. It is an irony in itself that blind assessment and placebos, which have proven
to “produce actual but unexplained therapeutic success” and rely upon a “direct link between
knowing and healing” (Sullivan 1993:213), have been illegitimatised in favour of providing
the clearest proof that a biomedical drug is producing a therapeutic effect observed.
Not undermining the usefulness of RCT for biomedical drug evaluation, its effect on other
medical systems should not be underestimated. The medical authorities of the 20th century
proved the therapeutic efficacy of ‘simulation’ – a word carefully avoided in the blind
assessment process – and used it for their own ends by imprisoning its valuable therapeutic
means. However, recent publications (Moermann 2002) have unravelled the practicability of
placebo effects for medical therapy, 107 years after the Polish physiologist, Waclaw
Sobieranski, revealed that “autosuggestion played a large role in healing” and that “much of
the healing properties of chemical medicine is in reality attributed to autosuggestion”
(Sobieranski 1895, quoted from Kaptchuk 1998:418).
2. Advantages and Limitations of RCTs
RCTs are designed to identify and isolate therapies. They can precisely test biomedical
pharmacological knowledge that is extrinsic to the clinical encounter, excluding effects of
belief, expectations, emotions, etc. (Sullivan 1993:225).
In the process of testing the efficacy of a drug, the element of ‘chance’ is the biggest problem.
How to account for the chances that someone may get better with or without taking the drug?
Clinical trials have tried to get as close to the ‘truth’ by including large numbers of people of
the same age, sex and with single diseases. Randomisation avoids any bias during the trial and
double-blind methodology excludes influences of suggestion, as neither the doctor nor the
patient knows whether the placebo or the drug is given (Ryan T. R., lecture 12.11.2002).
Because of the complexities involved in medicines, which are hard to verify, biomedicine
prefers looking at a single substance. Thus, biomedical pharmacology identifies the single
active ingredient in a drug and usually selects a single drug for trials (one reason why its
methods is difficult to apply to multi-compounded traditional remedies). The three main
factors involved in designing RCTs are low-cost, sustainability and local availability (Ryan T.
R., lecture 12.11.2002).
Several authors have criticised RCTs for their limited biomedical approach. Mark Sullivan’s
main point against RCT is that this method has diminished the “therapeutic potential of the
doctor-patient relationship and of the potential human recourses available in healing.”
(Sullivan 1993:213)
Till the 19th century, when medical authority was still unestablished among physicians,
patients had a major influence in directing the treatment process and making medical
decisions (Duden 1991). Along with biomedical authority taking charge, RCTs have
eliminated the patient involvement, because the experimental factors have to be as
‘impersonal’ and ‘controlled’ as possible.
Elisabeth Hsu argues that “efficacy” belongs to the “language” of biomedicine and should be
understood as a “means to exert control over medical knowledge.” (Hsu 1996:37). Giving
more importance to the actor’s position to evaluate the treatment process, she introduces the
aspect of “therapeutic quality” for the patient’s subjective perspective, as distinct from the
“therapeutic results” of the practitioner’s point of view, regardless of biomedical or alternative
backgrounds. The observers of the treatment evaluation are accounted for in the “therapeutic
efficacy” of the biomedical scientist and the “therapeutic success” of the medical
anthropologist, who takes into account the social, cultural, political and economic
circumstances in which the treatment takes place (Hsu 1996:38), thus enlarging the thrust area
of treatment efficacy within the disease-illness context.
Several studies proved that the doctor’s personality and empathic understanding of the patient
affects the treatment outcome (Moermann 2002:36-7). He also proved that merely the
physician’s knowledge during a RCT can bring about pain relief (Moermann 2002:32-3),
which shows the influence of thought in therapies that are not accounted for in RCTs, but are
often used in traditional medical systems.
Moermann could be criticised for neglecting the influence of the cultural and social status of
the medical profession. Medical anthropologists would argue that the doctor’s social status
and authority has an even stronger placebo effect. This would apply to various medical
cultures. Also the shaman in his special costume or the priest on his temple seat act from a
place of authority from the patient’s point of view.
3. Critical Appreciation of RCT in Traditional Tibetan Medicine
In Ayurveda and Tibetan medicine, the diagnosis of illness is made in terms of the balance
between five elements (Sanskrit panca mahabhuta; Tibetan `byung ba lnga) and three
humoural principles (Sanskrit dosa, Tibetan nyes pa). This balance is assessed through
skilled questioning about the patient's symptoms, behaviour and state of mind, feeling their
pulse, and observing their urine, tongue, and external appearance. “Feeling” and “observing”
constitute culturally valid epistemological means to arrive at therapeutic conclusions.
Tibetan pharmacology is based on the ability of the doctor to ‘taste’ the right combination of
plants. The Tibetan laboratory, so to speak, is on the tongue. The six tastes (sweet, salty,
bitter, astringent, hot and sour) determine how the ingredients will affect the five elements.
Sensitising the individual taste perception is part of the medical education. As part of their
examination, students have to identify plants with blind-folded eyes, simply by their taste.
The combination of the ingredients (varying from 4 to 100) is carefully calculated according
to the taste of the substances and their consequent effects on the humoural balance.
Moreover, “a medicinal plant has to be picked at a certain time of the year at which the
configuration of the five elements and three humoural principles in the environment
maximises its medicinal value. Other factors to be considered in gathering medicinal plants
include the compass direction of the slope on which they are found, the position of lunar and
planetary constellations at the time of gathering, the time of the day, the signs of specific birds
and animals in the natural surroundings as well as the state of mind of the person collecting
the plant. Different plants have to be washed, dried and preserved in different ways.” (Gerke,
Jacobson 1996:17). All of these factors are understood to effect the medicinal power of the
final drug. Spiritual practices such as consecrations through the recitation of mantras are often
seen as essential contributions to the final drug. Consecration can be understood as an
‘intentional suggestion’ and a ‘projection of concentrated thought’ onto the drug, involving
ritual practice. ‘Blessed’ medicines by a ‘high lama’ are considered ‘highly effective’ among
Tibetans. The principal appears similar to ‘suggestion’ in intended placebo effects.
Interestingly, RCT has been used to evaluate the efficacy of a Tibetan medical drug, Padma
28, produced by a Swiss company (Drabaek et al 1993, in Aschoff 1996, no. 525):
"36 patients with a median age of 67 years and a median duration of intermittent claudicatio of five years
were randomised to either active treatment with Padma 28 or placebo. The effect of treatment was quantified
by measurements of systemic and peripheral systolic blood pressures and by measurements of the pain-free
and the maximal walking distance on a treadmill. ...The group randomised to active treatment received two
tablets bid containing 340 mg of a dried herbal mixture ... of Padma 28. After active treatments, administered
over a period of four months in a double-blinded, randomised design, the patients allocated to this group
attained a significant increase in the pain-free walking distance. The patient-group receiving placebo
treatments did not show any significant changes in either the pain-free or the maximal walking distance."
This trial suggests that RCT can be used in evaluating traditional Tibetan medicine for
classified biomedical diseases and thus make it available to the European market, which
would otherwise remain closed due to legal restrictions. In fact, adopting RCT and Western
medical research methodologies is the only legal and possible way for Tibetan drugs to be
produced and accepted in most of Europe and North America.
I have to add here that all 28 ingredients of Padma 28 have been botanically identified and the
chemical active components have been isolated and classified. The drug has been
manufactured under Western standard laboratory conditions in Switzerland. Considering the
earlier exposition on traditional Tibetan pharmacology, it becomes clear that the
manufacturing process as well as the RCT does not account for any of the principles of the
Tibetan pharmacological epistemic system and that the trial does not measure the therapeutic
effect on the balance of the humours and elements.
Moreover, the individual constitution is ignored in the RCT. But it is considered important in
the traditional system and includes disease classifications of ‘hot’ and ‘cold’, which implies
that patients having the same disease could be treated differently because of their ‘hot’ or
‘cold’ nature. We also need to consider that none of the isolated active principles is relevant in
the cultural setting and knowledge system of a Tibetan pharmacologist, who is concerned
with the taste of the raw ingredients and the final drug for its effects on the humours.
Still, RCT proved that the recipe Padma 28, which is of Buryat origin, is effective in cases of
stable intermitted claudicatio. Whether this is ethically, culturally, medically or
anthropologically an acceptable path to introduce Tibetan medicine to Western patients is still
widely debated. Medical anthropologists argue that medicines should be evaluated within the
framework where they were established. For Tibetan medicine this would mean that it would
never be introduced to the West on a large scale, unless the biomedical legal establishment
changes. This brings us back to the first note of how biomedicine established its supreme
authority and decision power in Europe and America through illegitimatising the ‘placebo
effect’ which has a direct link between knowledge/mind and healing. Consequently, all
medical traditions which are characterised by direct links between knowledge and healing
have been illegitimatised in the same way by the biomedical definition of ‘therapeutic
efficacy’.
Incidentally, human ‘ignorance’ (Tib. ma rig pa) is mentioned as primary cause of illness in
Tibetan medical texts. Having realised the ‘power of mind’ as causing illness, its therapeutic
qualities have also been utilised effectively in Tibetan healing rituals.
4. Proposals for the Evaluation of Efficacy of Ethnomedicinal Plants
Bernard Ortiz de Montellano made an interesting proposal to evaluate Aztec medicinal plants
as early as 1975. He was interested in the pure native view on medicine, but used modern
knowledge to evaluate the effectiveness of Aztec medicinal plants. Montellano argued that
with 16 of the 25 tested plants producing the effects claimed in Aztec sources, that – apart
from magic and religion - there must have been a strong empirical knowledge among the
Aztecs, which should receive more attention (Montellano 1975: 220). In anticipation of his
early research, Montellano (1981) and Browner et al (1988) proposed “four levels of
confidence” according to which herbal medicines could be evaluated. Their data showed that
“two distinct ethnomedical systems can reach similar therapeutic understandings through
different analytical routes” (Browner et al 1988:686-8). The authors claim that their approach
can be utilised to organise culture-specific material into standardised comparable units, and
that biomedicine - despite all its limitations and culture-constructed categories - still offers
useful methodologies to analyse and compare ethnographic materials. (Browner et al
1988:689).
This approach of traditional treatment evaluation was heavily criticised by Byron Good who
accused Browner et al for “mapping local cultural phenomena onto a biomedical grid”. Good
argued that “the task of medical anthropology can never be simply to discover links between
medical cultures and biology”, and that “illness realities are never reflections of biology.
Biology becomes human illness only as it is given meaning....” (Browner et al 1988:693-4).
Conclusion
Evaluating treatment efficacy is a very complex undertaking. Biomedicine has developed
approaches, such as double-blind randomised clinical trials, which are useful to evaluate the
efficacy of single drugs in a biomedical context. Apart from being expensive, trials only take
into account isolated active substances and their effect on disease, ignoring patient-doctor
relationships and socio-political aspects of illness (Sullivan 1993, Hsu 1996).
The deconstruction of the role of the ‘placebo effect’ in history (Kaptchuk 1998) revealed its
abuse in the design of clinical trials, undermining and illegitimatising its therapeutic effect.
Recent studies on placebos (Moermann 2002) led again to an increasing integration of
‘suggestion’ into medical practice, though keeping an extrinsic biomedical view. The effect of
intentional thought and suggestion, apart from use in placebos, has not yet received sufficient
attention, especially in traditional medical systems which often have a detailed knowledge
system on the healing power of the mind.
The selective ’disease-drug view’ of RCTs is necessary for arriving at an unbiased evaluation,
and perhaps useful for comparison and classification of data, but seems highly inappropriate
for evaluating traditional medical drugs from their indigenous cultural view point. The
examples of Aztec medicine (Montellano 1975) and cross-cultural ethnomedical research
(Browner et al 1988) show that biomedical methodologies can be used to evaluate the
efficacy of medicinal plants to a certain extent if the native aetiology of the drug use is taken
into account. However, this applies to single herbs only and still uses a biomedical restricted
model.
The epistemology of the Tibetan multi-compound pharmacology, for example, is much more
complex. Any conducted RCT will account only for the efficacy of the ‘traditional’ drug
according to biomedical disease categories, which is essential if the tradition wants to find a
legal entry to the Western health market. However, native aetiologies of the individual
constitution, the three humours, five elements and six tastes are ignored in such trials. Medical
anthropologists may be able to create more awareness on these evaluation issues and may take
part in designing new methodologies to evaluate therapeutic efficacy involving categories of
indigenous knowledge systems for assessing and evaluating the therapeutic effect on the
principles used in the traditional medical system itself.
References
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