Placebo Treatments, Informed Consent, and ‘The Grip of a False Picture’
ABSTRACT:
It is widely supposed that the prescription of placebo treatments to patients for
therapeutic purposes is ethically problematic, on the grounds that the patient cannot give
informed consent to the treatment, and is therefore deceived by the physician. This claim, I
argue, rests on two confusions; one concerning the meaning of “informed consent” and its
relation to the information available to the patient, and one concerning the relation of body
and mind.
Taken together, these errors lead naturally to the conclusion that the prescription of
placebos to unwitting patients is unethical. Once they are dispelled, I argue, we can see that
providing “full” information against a background of metaphysical confusion may make a
patient less informed; and that the “therapeutic” goal of relieving the patient of such
confusions is properly the duty of the philosopher rather than the physician. Therapeutic
placebos therefore do not violate the patient’s informed consent, or the ethical duties of the
doctor.
I. INTRODUCTION
It is widely supposed that the prescription of placebo treatments to patients for
therapeutic purposes (rather than in the context of placebo-controlled trials) is ethically
problematic, on the grounds that the patient cannot give informed consent to the treatment.i
i
For the purpose of isolating the ethical issue, I will disregard the growing evidence that even “open”
placebos, where the patient is fully aware of their inert nature, can be efficacious.[1] I will also limit
the discussion, for purposes of conceptual clarity, to “pure” placebos. While physicians sometimes
prescribe so-called “impure” placebos – substances which are not pharmacologically inert but have
no known effect on the patient’s specific condition – the soundness of this concept has been
This claim, I argue, rests on two confusions; once these are dispelled, it can be maintained
only by taking an implausible view of the physician’s duties, qua physician, to the patient.
The first confusion primarily affects theorising about the meaning of “informed
consent”, and has to do with the relation between information and informedness. The second
affects both the patient purportedly “deceived” by receiving a placebo treatment, and those
of us who speculate about his or her decision-making; and it concerns the relation of body
and mind. Taken together, they lead naturally to the conclusion that the prescription of
placebos to unwitting patients is unethical; however, as I shall show, they are both false.
There are some similarities between my approach and that recently advanced by Gold
and Lichtenberg in these pages;[4] however, there are also significant differences. While
both views target “Cartesian” accounts of the mind-body relation, mine is concerned
specifically with an underlying Cartesian intuition, rather than with any particular
theoretical position. And whereas Gold and Lichtenberg distinguish between lying and
deceiving a patient in order to defend a virtues-based paternalism against concerns about
patient autonomy, my approach denies that any such deception, or violation of autonomy,
takes place.
I begin by briefly sketching the main ethical case against placebo treatments, to which
my argument responds. Following this sketch, I discuss in turn the two confusions which the
case involves, before examining the remaining duties towards her patient which a physician
could reasonably be thought to break by the provision of placebo treatments.
For purposes of argument, I assume here that at least some placebo treatments are
efficacious in at least some circumstances. This is not uncontroversial. Likewise, while the
conceptual soundness of the term “placebo” has been forcefully challenged [2, 3, 5, 6], I do
not address those concerns in the present paper; my analysis here focusses on the concepts
disputed. [2, 3] I therefore discuss only “pure” placebos in what follows, and reserve judgement
about whether the arguments are similarly applicable to a wider class of treatments.
of information and informed consent as they pertain to placebo treatments, rather than on
the placebo concept itself.
II. THE CASE AGAINST PLACEBO TREATMENTS
The American Medical Association is unambiguous in condemning the prescription of
placebos to unwitting patients; the physician may administer a substance that “has no
specific pharmacological effect upon the condition being treated … for diagnosis or treatment
only if the patient is informed of and agrees to its use.”[7] Such treatments are widely
regarded as deceptive, and therefore as infringing on the autonomy and informed consent of
the patient.[8] In Britain, the House of Commons Select Committee on Science and
Technology likewise concluded that placebo treatment “removes informed patient choice,
because the patient is being asked to make decisions under false pretences”, rendering that
choice “meaningless”.[9] Nevertheless, these conclusions have been challenged,[4, 10-12]
and the practice of physicians reflects reasonably widespread ethical approval; 62% of US
rheumatologists and internists responding to a recent survey believed the practice to be
permissible, 3-5% reported administering such treatments on a regular basis, and only 5% of
those explicitly described them to patients as placebos when doing so.[13] In the UK, 12% of
general practitioners report using “pure” placebos at least once in their career, and 1% at
least once per week; 66% regarded the practice as ethical.[14]ii
The objections revolve around the familiar principle of “informed consent”; or the
notion, first explicitly articulated in Salgo v. Leland Stanford, Jr. University Board of
Trustees,[15] that a patient must “with substantial understanding and in substantial absence
of control by others, intentionally [authorize] a health professional to do something” before
any such procedure can be carried out.[16] The reasoning is not hard to see; if I am not told,
ii
It should be noted that these empirical studies have been criticised in the literature.[2,3]
Nevertheless, the ethical and conceptual issues discussed here are worth pursuing even if the actual
use of placebo treatments turns out to be very rare indeed.
as a patient, that the proposed treatment is pharmacologically inert, then I am not in an
epistemic position to consent to being administered such a substance. A salient piece of
information, which we have good reason to think might affect my decision, has been
consciously withheld from me by my physician. I therefore lack, in making my decision,
substantial understanding of the treatment; arguably, too, I lack substantial absence of
control by another, since my doctor is manipulating my decision by restricting information
in this way.
Put this way, the argument is an intuitively attractive one, and closely parallels a
central line of reasoning in Kant’s ethics. As he argues in the Groundwork of the
Metaphysics of Morals, a lying promise is not possible under the Formula of Humanity,
since “the man whom I seek to use … by such a promise cannot possibly agree with my way
of behaving to him, and so cannot himself share the end of the action.”[17] In the placebo
case, we may presume that the patient does share the doctor’s end, which is to treat him, or
at least to relieve his symptoms; nevertheless, the argument goes, it is impossible for him to
agree with the treatment, since by definition he does not know what it is he is agreeing to.
Defenders of placebo treatments have tended, in the main, to reject this deontological
reasoning, and to argue that such violations of informed consent as are involved in their
prescription are morally justified in view of other considerations, and that patient autonomy
is therefore not a moral absolute.[e.g. 4, 10, 12, 18] Nevertheless, physicians’ intuitions do
not appear to support such claims; 82% of British general practitioners reported that they
believed placebos to be ethically unacceptable when they involved deception.[14] I have no
wish to further prosecute the venerable debate between deontological, virtue-theoretic, and
consequentialist views of ethics here; what I wish to demonstrate is that even deontological
arguments against deception of a patient do not preclude placebo treatments, properly
understood.iii
iii
The argument thus also obviates the felt need for “negatively informed consent” as an alternative to
informed consent in placebo cases. [19]
Accordingly, I won’t attempt here to refute a second influential and widely-held [14]
line of ethical argument against placebo treatments, which concerns the resulting potential
for a breakdown of trust between patients and physicians.[6, 11] This seems to me a
significant objection, but not one that establishes the moral impermissibility of placebo
treatments. As a piece of consequentialist rather than deontological reasoning, what it shows
instead is that physicians must carefully and cautiously weigh up the pros and cons of
prescribing placebo treatments in individual circumstances; it does not forbid placebo
treatments as such. Indeed, it won’t affect the reasoning of a physician who considers himself
or herself morally obliged to treat a particular patient in this way. Moreover, if the argument
I make in this paper becomes better and more widely understood, the potential for a
breakdown in trust as a result of such treatments will be reduced.
In what follows, I shall contend: firstly, that the concern about deception of the patient
is misguided, and that the withholding of information in this way may in fact raise the level
of informedness with which the patient consents to treatment; and secondly, that in cases
where the patient would have decided differently given the information that the proposed
treatment was a placebo, withholding the information would indeed have raised his or her
level of informedness.
III. HAVING MORE INFORMATION IS NOT BEING MORE INFORMED
It is natural to assume a simple grammatical relationship between information and
informedness; to provide somebody with information is to inform them, and to be informed
is to have been provided with information. It is a natural assumption, but – at least as the
term is meant in the phrase “informed consent” – it is a false one.
What we require for informed consent, recall, is “substantial understanding” of the
procedure in question. But of course, simply gaining some pertinent extra datum does not
necessarily increase one’s understanding; and in some cases it may reduce it, by causing (or
exacerbating) confusion. “Raw” scientific data, Sabina Leonelli demonstrates, are neither
true nor false in themselves, but require interpretation in the context of particular scientific
theories.[20] More generally, as David Lewis has pointed out,
(e)xplanatory information may be provided in such a way that the recipient has
difficulty in assimilating it, or in disentangling the sort of information he wants from
all the rest. He may be given more than he can handle, or he may be given it in a
disorganized jumble. Or he may be given it in so unconvincing a way that he just
doesn’t believe what he’s told. If he is hard to convince, just telling him may not be an
effective way to provide him with information.[21]
There are numerous ways, then, in which being provided with relevant information may
nonetheless fail to inform us. Not every piece of information we can give to a patient will
contribute positively to his or her “substantial understanding” of the proposed treatment for
which consent is required.
In some circumstances, against a background of false beliefs, extra information may
have a negative effect on our overall understanding. To take a toy example, suppose that I am
visiting the United Kingdom, maps of which I have spent my life unwittingly looking at
upside-down, and wrongly believe London to be several hundred miles north of my current
location in Edinburgh. Wishing to drive to London to speak at a conference, I enquire of a
passer-by which direction is north. But though he tells me truthfully, this information does
not help me find my way to London to give my talk; in fact, it only deepens my confusion.
Throughout the Philosophical Investigations, Ludwig Wittgenstein constantly refers to
the idea of being “held captive” by “a picture”.[22] “Pictures”, in this sense, are particular
ways of understanding the world, often useful or fruitful in a limited range of application, but
which lead us astray when, as we are prone to do, we apply them too widely.[23] It is “in the
grip” of these false pictures, these systematically misleading conceptions of the world, that
gaining new information is most likely to further diminish our understanding of the
situation; the duty of a philosopher, on this view, is therefore the “therapeutic” one of
releasing their hold on us, and allowing us to see these representations of the world as
merely particular cognitive tools appropriate to particular contexts of reasoning.[24]
As I shall now argue, much of the sense of impropriety which is felt about “deceiving” a
patient by the prescription of placebo treatments derives from just such a false picture of the
relation between mind and body. In particular, the idea that the patient would have chosen
differently if told the treatment was pharmacologically inert depends on the assumption that
the patient is himself or herself in the grip of that picture. Not only is that picture
demonstrably false, I will go on to show, but the “Wittgensteinian therapy” of loosening its
grip is not properly the concern of the physician.
IV. THE FALSE PICTURE OF “NAÏVE CARTESIANISM”
As a matter of routine, doctors do not tell patients the biochemical details of how and
why their treatments work. Patients receiving ibuprofen are not told about cyclooxygenaseinhibition, nor those receiving penicillin about DD-transpeptidase catalysis rates. Nobody, I
think, sees anything untoward about this; the great majority of patients simply lack the
background knowledge necessary to make sense of this information. It is not the
responsibility of doctors, moreover, to remedy this lacuna in their understanding.
68% of physicians who administer placebos report describing them to patients as some
variation of “a medicine not typically used for your condition but [which] might benefit
you.”[13] An alternative, and more fastidious, locution which has been suggested in the
literature is “I would like to offer you a pill which I believe can help lessen your suffering. I
do not know exactly how it works. I have other pills to offer whose mechanism is clearer, but
I am not sure that they will work better for you, and they may also entail more serious side
effects.”[12] Both of these descriptions are plainly true, but are widely regarded as
nevertheless deceptive, since they withhold the information that the pill or medicine is
pharmacologically inert. But as noted above, it is entirely normal for physicians to leave out
details about the precise causal pathways by which medicines work. So what, exactly,
differentiates placebo cases from more conventional prescriptions?
One possible answer might be that we have reason to think the patient will not consent
if informed the treatment is a placebo, whereas that is less likely to happen in more standard
cases. Thus, by deliberately withholding information relevant to the decision, the doctor
violates the Gricean “Maxim of Quantity” and thereby wrongfully implies that the treatment
is an active one.[25]iv But if true, this response only postpones the issue; we are still left with
the question of why patients might refuse inert treatments.
For both questions, the explanatory intuition seems to be connected with a sense of
deception or trickery, an association which even proponents of placebo treatments have
sometimes conceded; see e.g. the titles of [10, 11, 18, 26]. The placebo does not act on the
body, on this view, but merely “fools” the mind into believing that the body has been treated,
thereby causing it to trigger or accelerate the body’s own supplementary healing
mechanisms.
This dichotomy, between acting on the patient’s body and “merely” acting on his or her
psyche, is an intuitively appealing one. However, it results from what, following
Wittgenstein, we may term a false picture of the mind/body relation. What it presumes is
that there is a total causal separation between the mind and body, such that acting on the
mind is not thereby also acting on the body. Call this picture “naïve Cartesianism”.
The notion of a “Cartesian fallacy” or “an outmoded Cartesian prejudice” underpinning
the anti-placebo case has been raised elsewhere in the literature.[4, 12] By referring to naïve
Cartesianism, however, I wish to emphasise explicitly that the picture in question is not part
iv
On this understanding, the distinction drawn by Gold and Lichtenberg[4] and Cohen and Shapiro
[26], among others, between “lying” and “deceiving” would be seen as insignificant from the
perspective of linguistic pragmatics, and thus rather shaky ground on which to build an ethical
defence of clinical placebo use.
of any contemporary theoretical position. That is, to sustain the argument I am making, we
need not reject sophisticated modern versions of mind-body dualism like David
Chalmers’;[27] and their adherents are likewise not committed to the moral impermissibility
of placebo treatments. For those who believe in any form of mind/brain identity, naïve
Cartesianism is clearly false; acting on the mind is acting on the brain, and the brain is
assuredly part of the body. But for those more sympathetic to dualist reasoning, this “folk”
version of the theory is similarly plainly false. Indeed, no further demonstration of its
falsehood is necessary than the very fact that placebos work. The placebo may have no direct
pharmacological effect, but it has a measurable and observable indirect one, mediated by
complex biopsychosocial mechanisms that we do not as yet understand very well.[28] One
thing we do know about the mechanisms; they don’t seem to be dependent on trickery, or
“fooling” the mind, since – again – placebos seem to be at least somewhat effective even
when the patient is informed.[1]
The suggested locutions are therefore perfectly accurate; the treatment is known to
relieve symptoms, and we’re not really sure why, or what the causal pathways are. This is the
basic information which the patient requires to make an informed decision; and given the
prevalence of belief in the naïve Cartesian picture, further information is not only
superfluous, but is apt to actively misinform the patient as to the nature and effect of the
treatment.
V. WHAT DOCTORS DO, AND WHAT PHILOSOPHERS DO
The root of the Kantian case against false promising, we saw, was that the promisee
cannot possibly consent to be deceived, and so cannot share the promissor’s ends. We have
defused the first part of this worry as it applies to placebo treatments; that the treatment is
pharmacologically inert is a merely incidental part of what the patient is asked to consent to,
at a level of causal detail far beyond what she standardly needs to understand her decision.
By way of insurance, though, we can also disregard the second part of the Kantian worry; the
ends of the doctor in most circumstancesv are exactly those of the patient. “The central aim of
medicine is making people better,” as the House of Commons report quoted above held;[9]
and in this respect there seems to be no real worry about the deception resulting in a use of
the patient merely as a means to the doctor’s own ends. This enables us to establish
counterfactual consent to treatment by placebo. That is, even if we take its placebo nature to
be an essential feature of the treatment, given the aim of getting better the patient would
have consented to the treatment as long as he or she were in possession of all relevant
information, including the falsity of naïve Cartesianism.vi
But even if we know intellectually that the naïve Cartesian picture is false, it is no easy
matter to shake its intuitions. This is what Wittgenstein means by being “held captive” or
“caught in the grip” of such pictures; they are not merely propositions or descriptions of the
world, with which we may agree or disagree, but are buried deep in our understanding of the
world, and in the grammar of our language for talking about it. The proper role of the
philosopher, Wittgenstein therefore holds, is in its own fashion therapeutic; it is to diagnose
the resilient metaphysical confusions which afflict us, and to relax their grip, allowing us to
“go on” in the world, untroubled by philosophical perplexities.
But this “therapy” is very different in its content from that pursued by the doctor. The
whole duty and aim of the doctor qua doctor is, again, to make the patient better. Correcting
the patient’s metaphysical errors is no part of the doctor’s duties; and it is probably not high
on a sick patient’s list of priorities either. That is to say, a doctor who sought to assuage his or
her conscience by fastidiously ensuring that the patient’s consent is fully informed would
end up thwarting the patient’s ends in the matter just as surely as one who failed to prescribe
v
Of course, we can imagine a situation where the doctor prescribes a placebo so as to, e.g. get a
troublesome or annoying patient off his back.[12] I do not refer to such cases.
vi
So-called “Full Information” accounts of value are an influential branch of contemporary metaethics; see e.g. [29].
what he or she considered to be the best available treatment due to the supposed logical
impossibility of the patient’s consenting to being deceived.
Leaving it to the physician to decide how much information a patient needs looks, of
course, very much like paternalism; and despite the enthusiasm of some pro-placebo
ethicists [2, 10], paternalism is not widely favoured in contemporary medical ethics. Does the
argument made here thereby readmit paternalism “by the back door”?vii If so, I think it’s a
relatively innocuous, second-order or “epistemic” form of paternalism; the doctor is not
asked to make an evaluative judgement about what is best for the patient, but a factual one
about which information will render the patient more informed and which not.
The duty of the physician is to treat the patient as efficaciously as possible, subject to
the patient’s informed consent to the treatment. Where, in the doctor’s judgement, the best
treatment is a placebo, withholding the fact that it is inert does not violate the patient’s
informed consent. Either the fact would simply have been irrelevant to the patient’s decisionmaking process, or – if the patient was “in the grip” of the naïve Cartesian picture – it would
have reduced the level of the patient’s informedness, and the quality of consent.
vii
I thank an anonymous referee for pressing this concern.
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