Evidence and Non-Evidence Based Treatment Options
tashrifie
4
Limitations to Evidence-
Based Practice
THOMAS MAIER
The promotion of evidence-based medicine
(EBM) or, more generally, of evidence-based
practice (EBP) has strongly characterized
most medical disciplines over the past 15 to 20
years. Evidence-based medicine has become a
highly influential concept in clinical practice,
medical education, research, and health
policy. Although the evidence-based approach
has also been increasingly applied in related
fields such as psychology, education, social
work, or economics, it was and still is pre-
dominantly used in medicine and nursing.
Evidence-based practice is a general and
nonspecific concept that aims to improve
and specify the way decision makers should
make decisions. For this purpose it delineates
methods of how professionals should retrieve,
summarize, and evaluate the available empir-
ical evidence in order to identify the best
possible decision to be taken in a specific
situation. So EBP is, in a broader perspective,
a method to analyze and evaluate large
amounts of statistical and empirical infor-
mation to understand a particular case. It is
therefore not limited to specific areas of sci-
ence and is potentially applicable in any field
of science using statistical and empirical data.
Many authors often cite Sackett, Rosenberg,
Muir Gray, Haynes, and Richardson’s (1996)
article entitled “Evidence-based medicine:What
it is and what it isn’t” as the founding deed of
evidence-based practice. David L. Sackett (born
1934), an American-born Canadian clinical
epidemiologist, was professor at the Department
of Clinical Epidemiology and Biostatistics of
McMaster University Medical School of Ham-
ilton, Ontario, from 1967 to 1994. During that
time, he and his team developed and propagated
modern concepts of clinical epidemiology.
Sackett later moved to England, and from 1994
to 1999,he headed the NationalHealth Services’
newly founded Centre for Evidence-Based
Medicine at Oxford University. During that
time, he largely promoted EBM in Europe by
publishing articles and textbooks as well as
by giving numerous lectures and training
courses. David Sackett is seen by many as the
founding father of EBM as a proper discipline,
although he would not at all claim this position
for himself. In fact, Sackett promoted and elab-
orated concepts that have been described and
used by others before; the origins of EBM are
rooted back in much earlier times.
The foundations of clinical epidemiology
were already laid in the 19th century mainly by
French, German, and English physicians sys-
tematically studying the prevalence and course
of diseases and the effects of therapies.
As important foundations of the EBM-
movement, certainly the works and insights
of the Scottish epidemiologist Archibald
(Archie) L. Cochrane (1909–1988) have to be
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mentioned. Cochrane, probably the true
founding father of modern clinical epidemi-
ology, had long before insisted on sound epi-
demiological data, especially from RCTs, as the
gold standard to improve medical practice
(Cochrane, 1972). In fact, the evaluation of
epidemiological data has always been one of
the main sources of information in modern
academic medicine, and many of the most
spectacular advances of medicine are direct
consequences of the application of basic epi-
demiologicalprinciplessuchas hygiene,aseptic
surgery, vaccination, antibiotics, and the iden-
tification of cardiovasular and carcinogenic risk
factors. One of the most frequent objections
against the propagation of EBM is, “It’s nothing
new, doctors have done it all the time.”
Rangachari, for example, apostrophized EBM
as “old French wine with a new Canadian
label” (Rangachari, 1997,p. 280) alluding to the
French 19th century epidemiology pioneer
Pierre Louis, who was an influencing medical
teacher in Europe and North America, and to
David L. Sackett, the Canadian epidemiologist.
Even though the “conscientious, explicit and
judicious use of the current best evidence in
making decisions about the care of individual
patients”(Sackettetal.,1996,p.71)seemstobea
perfectly reasonable and unassailable goal, EBM
has been harshly criticized from the very begin-
ningof its promotion(Berk&Miles Leigh,1999;
B. Cooper, 2003; Miles, Bentley, Polychronis,
Grey, and Price, 1999; Norman, 1999; Williams
& Garner, 2002). In 1995, for example, the edi-
tors of The Lancet chose to publish a rebuking
editorial against EBM entitled “Evidence-based
medicine, in its place” (The Lancet, 1995):
The voice of evidence-based medicine has
grown over the past 25 years or so from a
subversive whisper to a strident insistence that
it is improper to practise medicine of any
other kind. Revolutionaries notoriously exag-
gerate their claims; nonetheless, demands to
have evidence-based medicine hallowed as
the new orthodoxy have sometimes lacked
finesse and balance, and risked antagonising
doctors who would otherwise have taken
many of its principles to heart. The Lancet
applauds practice based on the best available
evidence–bringing critically appraised news
of such advances to the attention of clinicians
is part of what peer-reviewed medical journals
do–but we deplore attempts to foist evidence-
based medicine on the profession as a discip-
line in itself. (p. 785)
This editorial elicited a fervid debate carried
on for months in the letter columns of The
Lancet. Indeed, there was a certain doggedness
on both sides at that time, astonishing neutral
observers and rendering the numerous critics
even more suspicious. The advocates of EBM
ontheir partactedwith great self-confidence and
claimed noless than to establish a new discipline
and to put clinical medicine on new fundaments;
journals, societies, conferences, and EBM
training courses sprang up like mushrooms;
soon academic lectures and chairs emerged;
however, this clamorous and pert appearance of
EBM repelled many. A somehow dogmatic,
almost sectarian, tendency of the movement was
noticed with discontent, and even the deceased
patron saint of EBM, Archie Cochrane, had to
be invoked in order to push the zealots back:
How would Archie Cochrane view the
emerging scene? His contributions are
impressive, particularly to the development
of epidemiology as a medical science, but
would he be happy about all the activities
linked with his name? He was a freethinking,
iconoclasticindividualwithahealthycynicism,
who would not accept dogma. He brought an
open sceptical approach to medical problems
and we think that he would be saddened
to find that his name now embodies a
new rigid medical orthodoxy while the real
impact of his many achievments might be
overlooked. (Williams & Garner 2002, p. 10)
THE DEMOCRATIZATION
OF KNOWLEDGE
How could such an emotional controversy
arise about the introduction of a scientific
56 Overview and Foundational Issues
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method (Ghali, Saitz, Sargious, & Hershman,
1999)? Obviously, the propagation and refusal
of EBM have to be seen not only from a
rational scientific standpoint but also from
a sociological perspective (Miettinen, 1999;
Norman, 1999): The rise of the EBM move-
ment fundamentally reflects current develop-
ments in contemporary health care concerning
the allocation of information, knowledge,
authority, power, and finance (Berk & Miles
Leigh, 1999), a process becoming more and
more critical during the late 1980s and the
1990s. Medicine has, for quite some time, been
losing its prestige as an intangible, moral
institution. Its cost-value ratio is questioned
more and more and doctors are no longer
infallible authorities. We do not trust doctors
anymore to know the solution for any problem;
they are supposed to prove and to justify
what they do and why they do it. These
developments in medicine parallel similar
tendencies in other social domains and
indicate general changes in Western soci-
eties’ self-conception. Today we are living
in a knowledge society, where knowledge
and information is democratized, available and
accessible to all. There is no retreat anymore
for secret expert knowledge and for hidden
esoteric wisdom. The hallmarks of our time
are free encyclopedic databases, open access,
the World Wide Web, and Google©. In the
age of information, there are no limitations for
filing, storage, browsing, and scanning of
huge amounts of data; however, this requires
more and more expert knowledge to handle it.
So, paradoxically, EBM represents a new
specialized expertise that aims to democratize
or even to abolish detached expert knowledge.
The democratization of knowledge increas-
ingly questions the authority and self-
sufficiency of medical experts and has deeply
unsettled many doctors and medical scientists.
Of course, this struggle is not simply about
authority and truth; it is also about influence,
power, and money. For all the unsettled doc-
tors, EBM must have appeared like a guide for
the perplexed leading them out of insecurity
and doubt. Owing to its paradoxical nature,
EBM offers them a new spiritual home of
secluded expertise allowing doctors to regain
control over the debate and to reclaim
authority of interpretation from bold laymen.
For this purpose, EBM features and empha-
sizes the most valuable label of our time that is
so believable in science: science- or evidence-
based. In many areas of contention, terms like
evidence-based or scientifically proven are
used for the purpose of putting opponents on
the defensive. Nobody is entitled to question a
fact, which is declared evidence-based or
scientifically proven. By definition, these
labels are supposed to convey unquestioned
and axiomatic truth. It requires rather com-
plex and elaborate epistemological reasoning
to demonstrate how even true evidence-based
findings can at the same time be wrong,
misleading, and/or useless.
All these accounts and arguments apply in
particular to the disciplines of psychiatry and
clinical psychology, which have always had a
marginal position among the apparently
respectable disciplines of academic medicine.
Psychiatrists and psychologists always felt
particularly pressured to justify their actions
and are constantly suspected to practice
quackery rather than rational science. It is
therefore not surprising that among other
marginalized professionals, such as the general
practitioners, psychiatrists and psychotherapists
made particularly great efforts over the last
years to establish their disciplines as serious
matters of scholarly medicine by diligently
adopting the methods of EBM (Geddes &
Harrison, 1997; Gray & Pinson, 2003; Oakley-
Browne, 2001; Sharpe, Gill, Strain, & Mayou,
1996). Yet, there are also specific problems
limiting the applicability of EBP in these
disciplines.
EMPIRICISM AND REDUCTIONISM
In order to understand the role and function of
EBP within the scientific context, it may be
Limitations to Evidence-Based Practice 57
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helpful to give a brief overview of the theo-
retical backgrounds of science in general.
What is science and how does it proceed?
Science can be seen as a potentially endless
human endeavour that aims to understand
and determine reality. Not only are physical
objects matters of science, but also immate-
rial phenomena like language, history, soci-
ety, politics, economics, human behavior,
thoughts, or emotions. Starting with the Greek
scientists in the ancient world, but progress-
ing more rapidly with the philosophers of
the Enlightenment, modern science adopted
defined rules of action and standards of rea-
soning that delineate science from non-
scientific knowledge such as pragmatics, art,
or religion. Unfortunately, notions like sci-
ence, scientific, or evidence are often wrongly
used in basically nonscientific contexts caus-
ing unnecessary confusion.
The heart and the starting point of any
positive science is empiricism, meaning the
systematic observation of phenomena. Scien-
tists of any kind must start their reasoning with
observations, possibly refined through sup-
portive devices or experimental arrangements.
Although positive science fundamentally
believes in the possibility of objective per-
ception, it also knows the inherent weaknesses
of reliability and potential sources of errors.
Rather than have confidence in single obser-
vations, science trusts repeated and numer-
ous observations and statistical data. This
approach rules out idiosyncratic particularities
of single cases to gain the benefit of identifying
the common characteristics of general phe-
nomena (i.e., reductionism). This approach of
comprehending phenomena by analytically
observing and describing them has in fact
produced enormous advancements in many
fields of science, especially in technical dis-
ciplines; however, contrasting and confusing
gaps of knowledge prevail in other areas
such as causes of human behavior, mind–body
problems, or genome–environment inter-
action. Some areas of science are apparently
happier and more successful using the classical
approach of positive science, while other dis-
ciplines feel less comfortable with the reduc-
tionist way of analyzing problems. The less
successful areas of science are those studying
complex phenomena where idiosyncratic fea-
tures of single cases can make a difference, in
spite of perfect empirical evidence. This
applies clearly to medicine, but even more to
psychology, sociology, or economics. Medi-
cine, at least in its academic version, usually
places itself among respectable sciences,
meeting with and observing rules of scientific
reasoning; however, this claim may be wishful
thinking and medicine is in fact a classical
example of a basically atheoretical, mainly
pragmatic undertaking pretending to be based
on sound science. Inevitably, it leads to con-
tradictions when trying to bring together
common medical practice and pure science.
COMPLEXITY
Maybe the deeper reasons for these contradic-
tions are not understood well enough. Maybe
they still give reason for unrealistic ideas to
some scientists. A major source of misconcep-
tion appears to be the confused ontological
perception of some objects of scientific inves-
tigation. What is a disease, a disorder, a diag-
nosis? What is human behavior? What are
emotions? Answering these questions in a
manner to provide a basis for scientific reason-
ing in a Popperian sense (see later) is far from
trivial. Complex objects of science, like human
behavior, medical diseases, or emotions, are in
fact not concrete, tangible things easily acces-
sible to experimental investigation. They are
emergent phenomena, hence they are not stable
material objects, but exist only as transitory,
nonlocal appearances fluctuating in time. They
continuously emerge out of indeterminable
complexity through repeated self-referencing
operations in complex systems (i.e., autopoietic
systems). Indeterminable complexity or deter-
ministic chaos means that a huge number of
mutually interacting parameters autopoietically
58 Overview and Foundational Issues
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forma system, renderingany precise calculation
of the system’s future conditions impossible.
Each single element of the system perfectly
follows the physical rules of causality; however,
the system as a whole is nevertheless unpre-
dictable. Its fluctuations and oscillations can be
described only probabilistically. In order to
obtain reasonable and useful information about
a system, many scientific disciplines have
elaborated probabilistic methods of approach-
ing their objects of interest. Thermody-
namics, meteorology, electroencephalography,
epidemiology, and macroeconomics are only a
few such examples. Most structures in bio-
logical, social, and psychological reality can be
conceived as emergent phenomena in this sense.
Just as the temperature of an object is not a
quality of the single molecules forming the
object—a singlemoleculehas notemperature—
but a statistic description of a huge number of
molecules, human behavior cannot be deter-
mined through the description of composing
elements producing the phenomenon—for
example, neurons—even if these elements are
necessary and indispensable preconditions for
the emergence of the phenomenon. The char-
acteristics of the whole cannot be determined by
the description of its parts. When the precise
conditions of complex systems turn out to be
incalculable, the traditional reaction of positive
science is to intensify analytical efforts and to
compile more information about the compon-
ents forming the system. This approach allows
scientists to constantly increase their knowledge
about the system in question without ever
reaching a final understanding and a complete
determinationofthefunctionofthesystem.This
is exactly what happens currently in neurosci-
ences. Reductionist approaches have their
inherent limitations when it comes to the
understanding of complex systems.
A similar problem linked to complexity that
is particularly important is the assumed com-
parability of similar cases. In order to under-
stand an individual situation, science routinely
compares defined situations to similar situ-
ations or, even better, to a large number of
similar situations. Through the pooling of large
numbers of comparable cases, interfering
individual differences are statistically elimi-
nated, and only the common ground appears.
The conceptual assumption behind this pro-
cedure is that similar—but still not identical—
cases will evolve similarly under identical
conditions. One of the most important insights
from the study of complex phenomena is that
in complex systems very small differences in
initial conditions may lead to completely dif-
ferent outcomes after a short time—the so-
called butterfly effect. This insight is well
known to natural scientists; however, clinical
epidemiologists do not seem to be completely
aware of the consequences of the butterfly
effect to their area of research.
FROM KARL POPPER TO
THOMAS S. KUHN
Based on epistemological considerations, the
Anglo-Austrian philosopher Karl Popper
(1902–1994) demonstrated in the 1930s the
limitations of logical empiricism. He reaso-
ned that general theories drawn from empiri-
cal observations can never be proven to be
true. So, all theories must remain tentative
knowledge, waiting to be falsified by contrary
observations. In fact, Popper conceived the
project of science as a succession of theories to
be falsified sooner or later and to be replaced
by new theories. This continuous succession of
new scientific theories is the result of natural
selection of ideas through the advancement of
science. According to Popper, any scientific
theory must be formulated in a way to render it
potentially falsifiable through empirical test-
ing. Otherwise, the theory is not scientific:
It may be metaphysical, religious, or spiritual
instead. This requires that a theory must be
formulated in terms of clearly defined notions
and measurable elements.
Popper’s assertions were later qualified as
being less absolute by the American philoso-
pher of science Thomas S. Kuhn (1922–1996).
Limitations to Evidence-Based Practice 59
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Hersen, M., & Sturmey, P. (2012). Handbook of evidence-based practice in clinical psychology, adult disorders : Adult disorders. John Wiley & Sons, Incorporated. Created from ashford-ebooks on 2021-11-23 18:29:03.
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h n W
ile y
& S
o n s,
I n co
rp o ra
te d . A
ll ri g h ts
r e se
rv e d .
Kuhn, originally a physicist, pointed out that in
real science any propagated theory could be
falsified immediately by contrary observations
because contradicting observations are always
present; however, science usually ignores or
even suppresses observations dissenting with
the prevailing theory in order to maintain the
accepted theory. Kuhn calls the dissenting
observations anomalies, which are—according
to him—always obvious and visible to all, but
nevertheless blinded out of perception in order
to maintain the ruling paradigm. In Kuhn’s
view, science will never come to an end and
there will never be a final understanding of
nature. No theory will ever be able to integrate
and explain consistently all the observations
drawn from nature. At this point, even the
fundamental limitations to logical scientific
reasoning demonstrated by Gödel’s incom-
pleteness theorems become recognizable (cf.
also Sleigh, 1995). Based on his considerations,
Kuhn clear-sightedly identified science to be a
social system, rather than a strictly logical and
rational undertaking. Science, as a social phe-
nomenon, functions according to principles of
Gestalt psychology. It sees the things it wants to
see and overlooks the things that do not fit.
In his chief work The Structure of Scientific
Revolutions, Kuhn (1962) gives several
examples from the history of science support-
ing this interpretation. It is in fact amazing to
see how difficult it was for most important
scientific breakthroughs to become acknowl-
edged by the contemporary academic estab-
lishment. Kuhn uses the notion normal science
to characterize the established academic sci-
ence and emphasizes the self-referencing
nature of its operating mode. Academic teach-
ers teach students what the teachers believe is
true. Students have to learn what they are taught
by their teachers if they want to pass their
exams and get their degrees. Research is mainly
repeating and retesting what is already known
and accepted. Journals, edited and peer-
reviewed by academic teachers, publish what
conforms with academic teachers’ ideas. Soci-
eties and associations—headed by the same
academic teachers—ensure the purity of doc-
trine by sponsoring those who confirm the
prevailing paradigms. Dissenting opinions are
unwelcome. Based on Kuhn’s view of normal
science, EBP and EBM can be identified as
classical manifestations of normal science. The
EBP helps to ensure the implementation of
mainstream knowledge by declaring to be most
valid what is best evaluated. Usually the cur-
rently established practices are endorsed by the
best and most complete empirical evidence;
dissenting ideas will hardly be supported by
good evidence, even if these ideas are right.
Since EBP instructs its adherers to evaluate the
available evidence on the basis of numerical
rules of epidemiology, arguments like plausi-
bility, logic consistency, or novelty are of little
relevance.
AN EXAMPLE FROM RECENT
HISTORY OF CLINICAL MEDICINE
When in 1982 the Australian physicians
Barry Marshall and Robin Warren dis-
covered Helicobacter pylori in the stomachs
of patients with peptic ulcers, their findings
were completely ignored and neglected by
the medical establishment of that time. The
idea that peptic ulcers are provoked by an
infectious agent conflicted with the prevail-
ing paradigm of academic gastroenterology,
which conceptualized peptic ulcers as a
consequence of stress and lifestyle. Although
there had been numerous previous reports of
helicobacteria in gastric mucosa, all these
findings were completely ignored because
they conflicted with the prevailing paradigm.
As a consequence Marshall and Warren’s
discovery was ignored for years because
it fundamentally challenged current scien-
tific opinion. They were outcast by the
scientific community, and only 10 years later
their ideas slowly started to convince more
and more clinicians. Now, 25 years later, it
is common basic clinical knowledge that
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Helicobacter pylori is one of the major causes
of peptic ulcers, and eradication therapy is
the accepted and rational therapy for gastric
ulcers. Finally, in 2005 Barry Marshall and
Robin Warren gained the Nobel Price for
their discovery (Parsonnet, 2005).
BENEFITS AND RISKS OF
EVIDENCE-BASED PRACTICE
The true benefits of EBP for patients and
society in terms of outcomes and costs have
not been proven yet—at least not through
sound empirical evidence (B. Cooper, 2003;
Geddes & Harrison, 1997). Nevertheless, there
is no doubt that the method has a beneficial
and useful potential. Many achievements of
EBP are undisputable and undisputed, hence
they are evident.
Owing to the spread of methodical skills in
retrieving and evaluating the available epi-
demiological evidence, it has become much
harder to apply any kind of obscure or
idiosyncratic practices. The experts’ commu-
nity, as well as the customers and the general
public, are much more critical toward
pretended effects of treatments and ask for
sound empirical evidence of effectiveness
and safety. It is increasingly important not
only to know the best available treatment, but
also to prove it. The EBP is therefore a helpful
instrument for doctors and therapists to justify
and legitimate their practices to insurance,
judiciary, politics, and society.
Furthermore, individual patients might be
less at risk to wrong or harmful treatment due to
scientific misapprehension. Of course, common
malpractice owing to inanity, negligence, or
viciousness will never be eliminated, not even
by the total implementation of EBP; however,
treatment errors committed by diligent and
virtuous doctors are minimized through careful
adherence to rational guidelines.
In general, clinical decision-making paths
have become more comprehensible and
rational, probably also due to the spread of
EBP. As medicine is in fact not a thoroughly
scientific matter (Ghali et al. 1999), continuous
efforts are needed to enhance and renew
rationality. The EBP contributes to this task
and helps clinicians to maintain rationality in a
job where inscrutable complexity is daily
business. In current medical education, the
algorithms of EBP are now instilled into stu-
dents as a matter of course. Seen from that
perspective, EBP is also an instrument of dis-
cipline and education, for it compels medical
students and doctors to reflect continuously all
their opinions and decisions scientifically
(Norman, 1999). Today EBP has a great
impact on the education and training of future
doctors, and it thereby enhances the uniformity
and transparency of medical doctrine. This
international alignment of medical education
with the principles of EBP will, in the long run,
allow for better comparability of medical
practice all over the world. This is an important
precondition for the planning and coordination
of research activities. Thus, the circle of nor-
mal science is perfectly closed through the
widespread implementation of EBP.
GENERAL LIMITATIONS TO
EVIDENCE-BASED PRACTICE
It has been remarked, not without reason,
that the EBP movement itself has adopted
features of dogmatic authority (B. Cooper,
2003; Geddes et al., 1996; Miles et al., 1999).
This appears particularly ironic, because EBP
explicitly aims to fight any kind of orthodox
doctrine. The ferocity of some EBP adherents
may not necessarily hint at conceptual weak-
nesses of the method; rather, it is more likely
a sign of an iconoclastic or even patricidal
tendency inherent to EBP. Young, diligent
scholars, even students, possibly without any
practical experience, are now entitled to criti-
cize and rectify clinical authorities (Norman,
1999). This kind of insurgence must evoke
resistance from authorities. If the acceptance
of EBP among clinicians should be enhanced,
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Hersen, M., & Sturmey, P. (2012). Handbook of evidence-based practice in clinical psychology, adult disorders : Adult disorders. John Wiley & Sons, Incorporated. Created from ashford-ebooks on 2021-11-23 18:29:03.
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te d . A
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it is advisable that the method is not only
propagated by diligent theoreticians, but
mainly by experienced practitioners.
One of the first and most important argu-
ments against EBP is reductionism (see earl-
ier, Welsby, 1999). Complex and maybe
fundamentally diverse clinical situations of
individual patients have to be condensed and
aggregated to generalized questions in order to
retrieve empirical statistical evidence. Import-
ant specific information about the individual
cases is inevitably lost owing to this general-
ization. The usefulness of the retrieved evidence
is therefore inevitably diluted to a very general
and dim level. Of course, there are some fre-
quently used standard interventions, which are
really based upon good empirical evidence
(Geddes et al., 1996).
EXAMPLES FROM CLINICAL
MEDICINE
Scabies, a parasitic infection of the skin, is
an important public health problem, mainly
in resource-poor countries. For the treatment
of the disease, two treatment options are
recommended: topical permethrin and oral
ivermectin. Both treatments are known to be
effective and are usually well tolerated.
The Cochrane Review concluded from the
available empirical evidence that topical
permethrin appears to be the most effective
treatment of scabies (Strong & Johnstone,
2007). This recommendation can be found
in up-to-date medical textbooks and is
familiar to any well-trained doctor.
Acute otitis media in children is one of the
mostcommondiseases,oneofthemaincauses
for parents to consult a pediatrician, and a
frequent motive for the prescription of antibi-
otics, even though spontaneous recovery is
the usual outcome. Systematic reviews have
shown that the role of antibiotic drugs for the
course of the disease is marginal, and there is
no consensus among experts about the
identification of subgroups who would poten-
tially profit from antibiotics. In clinical prac-
tice, in spite of lacking evidence of its benefit,
the frequent prescription of antibiotic drugs is
mainly the consequence of parents’ pressure
and doctors’ insecurity. A recent meta-analy-
sis (Rovers et al., 2006) found that children
youngerthan2yearsofagewithbilateralacute
otitis media and those with otorrhea benefited
to some extent from antibiotic treatment;
however, even for these two particular condi-
tions, differences were moderate: After 3–7
days, 30% of the children treated with antibi-
otics still had pain, fever, or both, while in the
control group the corresponding proportion
was 55%. So,the available evidence to guide a
clinicianwhentreatinga childwith acuteotitis
media is not really significant and the decision
willmostlydependonsoftfactorslikeparents’
preferences or practical and economical
considerations.
Evidently, clinicians choosing these inter-
ventions do not really need to apply the algo-
rithms of EBP to make their decisions. They
simply administer what they had learned in
their regular clinical training. The opponents
of EBP rightly argue that the real problems in
clinical practice arise from complex, multi-
morbid patients presenting with several ill-
nesses and other factors that have to be taken
into account by the treating clinician. In order
to manage such cases successfully there is
usually no specific statistical evidence avail-
able to rely on. Instead, clinicians have to put
together evidence covering some aspects of the
actual case and hope that the resulting treat-
ment will still work even if it is not really
designed and tested for that particular situ-
ation. Good statistical evidence meeting the
highest standards of EBP is almost exclusively
derived from ideal monomorbid patients, who
are rarely seen in real, everyday practice
(Williams & Garner, 2002). It is not clear at
all—and far from evidence-based—whether
evidence from ideal cases can be transferred to
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more complex cases without substantial loss of
validity.
Another argument criticizing EBP points at
an epistemological problem. Because the EBP
operates retrospectively by evaluating what
was done in the past, it cannot directly con-
tribute to developing new strategies and to
finding new therapies. The EBP helps to
consolidate well-known therapies, but cannot
guide researchers toward scientific inno-
vations. No scientific breakthrough will ever
be made owing to EBP. On the contrary, if all
clinicians strictly followed recommendations
drawn from available retrospective evidence
and never dared to try something different,
science would stagnate in fruitless self-
reference. There is a basically conservative and
backward tendency inherent to the method.
Although it cannot exactly be called anti-
scientific on that account (B. Cooper, 2003;
Miles et al., 1999), EBP is a classical phe-
nomenon of normal science (Kuhn, 1962). It
will not itself be the source of fundamental
new insights.
Finally, there is an external problem with
EBP, which is probably most disturbing of all:
Production and compilation of evidence
available to clinicians is highly critical and
exposed to different nonscientific influences
(Miettinen, 1999). Selection of areas of
research is based more and more on economic
interests. Large, sound, and therefore scien-
tifically significant epidemiologic studies are
extremely complex and expensive. They can
be accomplished only with the support of
financially potent sponsors. Compared with
public bodies or institutions, private com-
panies are usually faster and more flexible in
investing important amounts of money into
medical research. So, for many ambitious sci-
entists keen on collecting publishable findings,
it is highly appealing to collaborate with
commercial sponsors. This has a significant
influence on the selection of diseases and
treatments being evaluated. The resulting body
of evidence is necessarily highly unbalanced
because mainly diseases and interventions
promising important profits are well evaluated.
For this reason, more money is probably put
into trials on erectile dysfunction, baldness, or
dysmenorrhea than on malaria or on typhoid
fever. So, even guidelines based on empirical
evidence—considered to be the ultimate gold
standard of clinical medicine—turn out to be
arbitrary and susceptible to economical, po-
litical, and dogmatic arguments (Berk & Miles
Leigh, 1999). So, EBP’s goals to replace
opinion and tendency by knowledge are in
danger of being missed, if the relativity of
available evidence is unrecognized. The
uncritical promotion of EBP opens a clandes-
tine gateway to those who have interests in
controlling the contents of medical debates and
have the financial means to do so. Biasing
clinical decisions in times of EBP is probably
no longer possible by false or absent evidence;
however, the selection of what is researched
in an EBP-compatible manner and what is
published may result in biased clinical deci-
sions (Miettinen, 1999). One of the most
effective treatment options in many clinical
situations—watchful waiting—is notoriously
under-researched because there is no com-
mercial or academic interest linked to that
treatment option. Unfortunately, there will
never be enough time, money, and workforce
to produce perfect statistical evidence for
all useful clinical procedures. So, even in
the very distant future, clinicians will still
apply many of their probably effective inter-
ventions without having evidence about
their efficacy and effectiveness; thus, EBP is a
technique of significant but limited utility
(Green & Britten, 1998; The Lancet, 1995;
Sackett et al., 1996).
EXAMPLE FROM CLINICAL
MEDICINE
Lumbar back pain is one of the most frequent
health problems in Western countries. About
5% of all low back problems are caused by
prolapsed lumbar discs. The treatment is
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mainly nonsurgical and 90% of acute attacks
of nerve root pain (sciatica) settle without
surgical intervention; however, different
forms of surgical treatments have been
developed and disseminated. Usually these
methods are considered for more rapid relief
in patients whose recovery is unacceptably
slow. The Cochrane reviewers criticize that
“despite the critical importance of knowing
whether surgery is beneficial for disc pro-
lapse, only four trials have directly compared
discectomy with conservative management
and these give suggestive rather than con-
clusive results” (Gibson & Waddell, 2007,
p. 1). They concluded:
Surgical discectomy for carefully selected
patients with sciatica due to lumbar disc
prolapse provides faster relief from the
acute attack than conservative management,
although any positive or negative effects on
the lifetime natural history of the underlying
disc disease are still unclear. (p. 2)
Surgical treatments of low back pain hold an
enormous commercial potential due to
the worldwide frequency of the problem. It
appears obvious that there are only a few
trials comparing conservative treatment
with surgery.
SPECIFIC LIMITATIONS TO EBP IN
PSYCHIATRY, PSYCHOTHERAPY,
AND CLINICAL PSYCHOLOGY
In psychiatry and psychotherapy, there is an
ambivalent attitude toward EBP. Attempting to
increase their scientific respectability, some
psychiatrists and clinical psychologists zeal-
ously adopted EBP algorithms (Geddes &
Harrison, 1997; Gray & Pinson, 2003; Oakley-
Browne, 2001; Sharpe et al., 1996) and started
evidence-based psychiatry. Others remain
hesitant or doubtful about the usefulness of EBP
in their field, and several authors have addressed
different critical aspects of evidence-based
psychiatry (Berk & Miles Leigh, 1999; Bilsker,
1996; Brendel, 2003; Geddes & Harrison, 1997;
Goldner & Bilsker, 1995; Harari, 2001; Hotopf,
Churchill, & Lewis, 1999; Lawrie, Scott, &
Sharpe, 2000; Seeman, 2001; Welsby, 1999;
Williams & Garner, 2002) with all of them
fundamentally concerning practical and scien-
tific particularities of psychiatry and clinical
psychology. Next, we shall try to clarify these
arguments.
The evidence-based approach to individual
cases is critically dependent on the validity of
diagnoses. This is an axiomatic assumption
of EBP, which is rarely analysed or scrutinized
in detail. If in a concrete case no diagnosis
could be attributed, the case would not be
amenable to EBP, and no evidence could
support decisions in such a case. If the diag-
nosis is wrong, or—even more intricate—if
cases labeled with a specific diagnosis are
still not homogenous enough to be comparable
in relevant aspects, EBP will provide useless
results.
EXAMPLE FROM PSYCHIATRY
According to DSM-IV, eating disorders are
classified in different categories: anorexia
nervosa (AN), bulimia nervosa (BN), binge
eating disorder (BED), and eating disorder
not otherwise specified (EDNOS). These
categories are clinically quite distinct and
diagnostic criteria are clear and easily
applicable. In spite of the phenomenological
diversity of the disease patterns, there is a
close relationship between the different forms
of eating disorders. In clinical practice,
switches between different diagnoses and
temporary remissions and relapses are fre-
quent. In the course of time, patients may
change their disease pattern several times:
At times they may not meet the criteria for
a diagnosis anymore, although they are not
completely symptom free, and later they may
relapse to a full-blown eating disorder again
or may be classified as having EDNOS.
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Corresponding to these clinical impressions,
longitudinal studies demonstrate that the sta-
bility of eating disorder diagnoses over time is
low ( Fichter & Quadflieg, 2007; Grilo et al.,
2007; Milos, Spindler, Schnyder, & Fairburn,
2005). Based on systematic evaluation of
the available evidence, however, treatment
guidelines give specific recommendations for
the different conditions (National Institute
for Clinical Excellence [NICE], 2004). For
patients with AN, psychological treatment on
an outpatient basis is recommended. The
treatment should be offered by “a service that
is competent in giving that treatment and in
assessing the physical risk of people with
eating disorders” (p. 60). For patients with
BN, the NICE guideline proposes as a pos-
sible first step to follow an evidence-based
self-help program. As an alternative, a trial
with an antidepressant drug is recommended,
followed by cognitive behavior therapy for
bulimia nervosa. In the absence of evidence to
guide the treatment of EDNOS, the NICE
guideline recommends pragmatically that
“the clinician considers following the guid-
ance on the treatment of the eating problem
that most closely resembles the individual
patient’s eating disorder” (p. 60). So even
though specific diagnoses of eating disorders
are not stable and a patient with AN might be
diagnosed with BN a few months later,
treatment recommendations vary consider-
ably for the two conditions. It becomes
obvious that different treatment recommen-
dations for seemingly different conditions
reflect rather accidental differences in the
availability of empirical evidence than real
differences in the response of certain condi-
tions to specific treatments. Hence, the guid-
ance offered by the guideline is basically a
rather unstable crutch, and of course, cogni-
tive behavior therapy or an evidence-based
self-help program might be just as beneficial
in AN or in EDNOS than it is in BN, even
though nobody has yet compiled the statis-
tical evidence to prove this.
What does the validity of a diagnosis mean?
The question concerns epistemological issues
and requires a closer look to the nature of
medical diagnoses with special regard to psy-
chiatric diagnoses. R. Cooper (2004) questioned
if mental disorders as defined in diagnostic
manuals are natural kinds. In her thoughtful
paper, the author concluded that diagnostic
entities are in fact theoretical conceptions,
describing complex cognitive, behavioral, and
emotional processes (R. Cooper, 2004; Harari,
2001). Diagnostic categories are based upon
observations, still they are strongly influenced
by theoretical, social, and even economical
factors. The ontological structure of psychi-
atric diagnoses is therefore not one of natural
kinds. They are not something absolutely
existing that can be observed independently.
Rather they are comprehensive theoretical
definitions serving as tools for communication
and scientific observation. Kendell and
Jablensky (2003) have also recently addressed
the issue of diagnostic entities and concluded
that the validity of psychiatric diagnoses is
limited. They analysed whether diagnostic
entities are sufficiently separable from each
other and from normality by zones of rarity.
They concluded that this was not the
case; rather, they concluded that psychiatric
diagnoses often overlap (R. Cooper, 2004;
Welsby, 1999), shift over time within the same
patient, and several similar diagnoses can be
present in the same patient at the same time
(comorbidity). Not surprisingly, diagnosis
alone is a poor predictor of outcome (Williams
& Garner, 2002). Acknowledging this hazi-
ness of diagnoses, one realizes these problems
when trying to match individual cases to
empirical evidence. When even the presence
of a correctly assessed diagnosis does not
assure comparability to other cases with the
same diagnosis, empirical evidence about
mental disorders is highly questionable
(Harari, 2001). Of course, limited validity does
not imply complete absence of validity, and
empirical evidence on mental disorders is
still useful to some extent; however, insight
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into the limitations is important and that
insight points out that psychiatric diagno-
ses represent phenomenological descriptions
rather than natural kinds. Several authors
have treated the same issue when writing
about the complexity of cases, the problem of
subsyndromal cases, and of single cases versus
statistical evidence (Harari, 2001; Welsby,
1999; Williams & Garner, 2002).
NONLINEAR DYNAMICS IN THE
COURSE OF DISEASES
It might be fruitful to look at evidence-based
psychiatry from another perspective and to
address the issues of complexity and nonlinear
dynamics. With regard to their physical and
mental functioning, humans can be conceptu-
alized as systems of high complexity
(Luhmann, 1995). This means that they cannot
be determined precisely, but only in a prob-
abilistic manner; however, probabilistic
determination is sufficient for most purposes in
observable reality. Human life consists fun-
damentally in dealing with probabilities.
Social systems and human communication are
naturally designed to manage complexity more
or less successfully. Medicine itself is a social
system (Luhmann, 1995) trying to handle the
effects of complexity (Harari, 2001), for
example, by providing probabilistic algo-
rithms for treatments of diseases. In most
situations, medicine can ignore the particular
effects emerging from the complex nonlinear
structure of its objects, although such effects
are always present. Only sometimes do these
effects become obvious and irritating, as for
example in fluctuations of symptoms in
chronic diseases, variations in response to
treatment, unexpected courses in chronic dis-
eases, and so on. Such phenomena can be seen
as manifestations of the butterfly effect (see
earlier). This insight questions deeply the core
principle of EBP that assumes that it is rational
to treat similar cases in the same manner
because similarity in the initial conditions will
predict similar outcomes under the identical
treatment. The uncertainty of this assumption
is particularly critical in psychiatry and psy-
chotherapy. In these fields similar appearance
is just a palliation for untraceable difference,
and this exact difference may crucially influ-
ence the outcome.
Addressing such problems is daily busi-
ness for psychiatrists and psychotherapists,
so their disciplines have developed special
approaches. Diagnostic and therapeutic pro-
cedures in these disciplines are much less
focused on critical momentary decisions, but
more on gradual, iterative procedures. Psy-
chiatric treatments and even more psycho-
therapy are self-referencing processes, where
assessments and decisions are constantly re-
evaluated. Instead, EBP focuses primarily on
decision making as the crucial moment of good
medical practice. One gets the impression that
EBM clinicians are constantly making critical
decisions, and after having made the right
decision, the case is solved. Maybe it is
because of this misfit between the proposals of
the method and real daily practice that many
psychiatrists are not too attracted by EBP.
EXAMPLE FROM PSYCHIATRY
The diagnosis of posttraumatic stress dis-
order (PTSD) was first introduced in the
third edition of the Diagnostic and Statis-
tical Manual of Mental Disorders (DSM-III)
in 1980. Before that time, traumatized
individuals were either diagnosed with dif-
ferent nonspecific diagnoses (e.g., anxiety
disorders, depression, neurasthenia) or not
declared ill at all. Astonishingly, the
newly discovered entity appeared to be a
clinically distinct disorder and the corre-
sponding symptoms (re-experiencing, avoid-
ance, hyperarousal) were quite characteristic
and easily identifiable. Within a short
time after its invention (Summerfield, 2001),
PTSD became a very popular disorder;
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clinicians and even patients loved the new
diagnosis (Andreasen, 1995). The key point
for the success of the new diagnosis was that
it is explicitly based on the assumption of an
external etiology; that is, the traumatic
experience. This conception makes PTSD so
appealing for the attribution of cause,
responsibility, and guilt is neatly separated
from the affected individual. PTSD allows
for the exculpation of the victim, a feature
that was particularly important when caring
for Holocaust survivors and Vietnam War
veterans. But what was almost proscribed
for some time after the introduction of PTSD
is now evidence-based: Preexisting individ-
ual factors play an important role in the
shaping of posttraumatic response. Whether
or not an individual develops PTSD after a
traumatic experience is not only determined
by the nature and the intensity of the
traumatic impact, but also by various
pretraumatic characteristics of the affected
individual. Furthermore, PTSD is not the
only posttraumatic mental disorder. A whole
spectrum of mental disorders is closely
linked to traumatic experiences, although
they lack the monocausal appearance of
PTSD. Anyway, the most frequent outcome
after traumatic experiences is recovery. In
the second rank of frequency comes major
depression. Borderline personality disorder
is fully recognized now as a disorder pro-
voked by traumatic experiences in early
childhood. Dissociative disorders, chronic
somatoform pain, anxiety disorders, sub-
stance abuse, and eating disorders are
equally related to traumatic experiences.
Not surprisingly, PTSD is often occurring as
a comorbid condition with one or more
additional disorder or vice versa. In clinical
practice, traumatized patients usually pre-
sent more complex than expected. This may
explain to some extent why PTSD was vir-
tually overlooked by clinicians for many
decades before its introduction, a fact that is
sometimes hard to understand by younger
therapists who are so familiar with the PTSD
diagnosis. At any rate, the high-functioning,
intelligent, monomorbid PTSD patient is
indeed best evaluated in clinical trials, but
rarely seen in everyday practice.
PTSD was right in the focus of research
since its introduction. Also from a scientific
point of view, the disorder is appealing
because it is provoked by an external event.
PTSD allows ideally for the investigation of
thehuman-environmentinteraction,whichisa
crucial issue for psychiatry and psychology in
general. The number of trials on diagnosis and
treatment of PTSD is huge, and the disorder is
now probably the best evaluated mental dis-
order. What is the benefit of the accumulated
large body of evidence on PTSD for cli-
nicians? There are several soundly elaborated
guidelines on the treatment of PTSD (Ameri-
can Psychiatric Association, 2004; Australian
Centre for PosttraumaticMentalHealth,2007;
NICE, 2005), meta-analyses, and Cochrane
Reviews providing guidance for the assess-
ment and treatment of the disorder. When we
look at the existing conclusions and recom-
mendations, we learn that:
� Debriefing is not recommended as routine practice for individuals who have
experienced a traumatic event.
� When symptoms are mild and have been present for less than 4 weeks after the
trauma, watchful waiting should be
considered.
� Trauma-focused cognitive behavior therapy on an individual outpatient basis
should be offered to people with severe
posttraumatic symptoms.
� Eye movement desensitization and repro- cessing is an alternative treatment option.
� Drug treatment should not be used as a routine first-line treatment in preference to
a trauma-focused psychological therapy.
� Drug treatment (Specific Serotonin Reuptake Inhibitors) should be considered
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for the treatment of PTSD in adults
who express a preference not to engage
in trauma-focused psychological
treatment.
� In the context of comorbid PTSD and depression, PTSD should be treated first.
� In the context of comorbid PTSD and substance abuse, both conditions should
be treated simultaneously.
These recommendations are obviously
clear, useful, and practical. They give real
guidance to therapists and do not leave much
room for doubts or insecurity. On the other
hand, they are basically very simple, almost
trivial. For trauma therapists, these recom-
mendations are commonplace and serve
mainly to endorse what they are practicing
anyway. The main points of the guidelines
for the treatment of PTSD could be taught in
a 1-hour workshop. The key messages of the
guidelines represent basic clinical knowl-
edge on a specific disorder as it has been
instructed in times before EBP. Through
their standardizing impact on the therapeutic
community, guidelines may in fact align and
improve the general service quality offered
to traumatized individuals, although this
effect has not yet been demonstrated by
empirical evidence.
The treatment of an individual patient
remains a unique endeavor where interper-
sonal relationship, flexibility, openness, and
cleverness are crucial factors. This challenge is
not lessened by evidence or guidelines.
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Limitations to Evidence-Based Practice 69
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Hersen, M., & Sturmey, P. (2012). Handbook of evidence-based practice in clinical psychology, adult disorders : Adult disorders. John Wiley & Sons, Incorporated. Created from ashford-ebooks on 2021-11-23 18:29:03.
C o p yr
ig h t ©
2 0 1 2 . Jo
h n W
ile y
& S
o n s,
I n co
rp o ra
te d . A
ll ri g h ts
r e se
rv e d .
c04 18 April 2012; 19:44:31
Hersen, M., & Sturmey, P. (2012). Handbook of evidence-based practice in clinical psychology, adult disorders : Adult disorders. John Wiley & Sons, Incorporated. Created from ashford-ebooks on 2021-11-23 18:29:03.
C o p yr
ig h t ©
2 0 1 2 . Jo
h n W
ile y
& S
o n s,
I n co
rp o ra
te d . A
ll ri g h ts
r e se
rv e d .