
Evolution could explain the placebo effect - mmahemoff
http://www.newscientist.com/article/mg21528812.300-evolution-could-explain-the-placebo-effect.html
======
tokenadult
Because the submitted article mentions the placebo effect, in the usual manner
of popular articles, perhaps I should share here some links that are helpful
for understanding what placebo effects are all about. Some of these online
links cite quite a few useful scholarly publications.

[http://www.sciencebasedmedicine.org/index.php/michael-
specte...](http://www.sciencebasedmedicine.org/index.php/michael-specter-on-
the-placebo-effect/)

"In other words, the best research we have strongly suggests that placebo
effects are illusions, not real physiological effects. The possible exception
to this are the subjective symptoms of pain and nausea, where the placebo
effects are highly variable and may be due to subjective reporting."

[http://www.sciencebasedmedicine.org/index.php/angells-
review...](http://www.sciencebasedmedicine.org/index.php/angells-review-of-
psychiatry/)

[http://theness.com/neurologicablog/index.php/the-rise-and-
fa...](http://theness.com/neurologicablog/index.php/the-rise-and-fall-of-
placebo-medicine/)

[http://www.sciencebasedmedicine.org/index.php/placebo-
effect...](http://www.sciencebasedmedicine.org/index.php/placebo-effects-
revisited/)

<http://www.skepdic.com/placebo.html>

[http://www.sciencebasedmedicine.org/index.php/revisiting-
dan...](http://www.sciencebasedmedicine.org/index.php/revisiting-daniel-
moerman-and-placebo-effects/)

The statement in the article kindly submitted here, "Someone suffering from a
low-level infection will recover just as nicely whether they take an active
drug or a simple sugar pill" should be interpreted as "Animals have a lot of
capacity for recovering from infections, and some treatments for infections
are indistinguishable in outcomes from doing nothing" until a citation for a
specific study involving infection in HUMAN subjects is brought into the
discussion. Usually the "placebo effect" is just the no-op effect of the body
healing over time with the body's own healing mechanisms, and the ONLY
reliable findings of placebo effects in human medicine, according to the
sources I am citing here, are self-reported subjective symptoms like pain and
discomfort, not physiologically verifiable improvement in disease states.

So let's not rush too fast to assume an explanation for a phenomenon until the
phenomenon is better defined. The submitted article goes on to discuss some
animal studies related to seasonal patterns of light and darkness. These
studies are related to the idea that the immune system is costly to maintain,
drawing on many physiological resources of the living organism. That's a
reasonably important point and is indeed the subject of much ongoing research.
But human beings, with their very complicated behavior patterns for adaptation
to many environments, probably have a system for regulating immune response
that is harder to observe. I note for the record and for your reading
enjoyment that the recent book he Folly of Fools: The Logic of Deceit and
Self-Deception in Human Life by Robert Trivers

[http://www.amazon.com/The-Folly-Fools-Deceit-Self-
Deception/...](http://www.amazon.com/The-Folly-Fools-Deceit-Self-
Deception/dp/0465027555)

includes a chapter, with some citations to scientific studies, about immune
system interaction with the brain suggesting a theory of self-deception in the
aid of bodily healing, on evolutionary grounds. The whole book is interesting,
and there is better established findings in it, so it is well worth a read
whatever other science says about placebo effects.

~~~
pella
_"In other words, the best research we have strongly suggests that placebo
effects are illusions, not real physiological effects"_

not true!

see:

" Recent research demonstrates that placebo effects are genuine
psychobiological phenomenon attributable to the overall therapeutic context,
and that placebo effects can be robust in both laboratory and clinical
settings. Evidence has also emerged that placebo effects can exist in clinical
practice, even if no placebo is given. Further promotion and integration of
laboratory and clinical research will allow advances in the ethical harnessing
of placebo mechanisms that are inherent in routine clinical care and the
potential use of treatments to primarily promote placebo effects."

from:

Placebo Effects: Biological, Clinical and Ethical Advances (Damien G Finniss,
Ted J Kaptchuk, Franklin Miller, and Fabrizio Benedetti

PMCID: PMC2832199 / NIHMSID: NIHMS169379

<http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2832199/>

~~~
tokenadult
I had better respond to this reply, which I see is NOT responsive to the
references I supplied in my original post. The link shown here, to a paper co-
authored by Ted J Kaptchuk, was surely submitted here in good faith, and I
thank the user who submitted it for that, but in fact Mr. Kaptchuk (he is NOT
a doctor and does not have good training in human physiology or research
methods) is well known as a promoter of ideas about healing through thinking
that have no factual basis and are not backed up by science. Basically all
roads to strong statements about "placebo effect" lead back to writings by Ted
J Kaptchuk, which are heavily promoted by press releases.

So I invite all readers of Hacker News to compare the references I supply in
this thread to the references supplied for the proposition that there are
clinically meaningful placebo effects that actually heal disease in human
patients. I especially encourage everyone reading this thread to review all
the cited studies with the checklist by Peter Norvig, Google's director of
research, "Warning Signs in Experimental Design and Interpretation"

<http://norvig.com/experiment-design.html>

in mind as you read the studies. Statistically valid, carefully designed
research studies do NOT show clinically useful placebo effects. Preliminary
studies by researchers who promote "alternative medicine" occasionally show
patient self-reports of benefits in subjective symptoms (pain or discomfort)
from placebo. Those have not been replicated by independent researchers.

Careful studies do not show healing of disease from administering placebos or
by other mind-over-matter processes. Extraordinary claims require
extraordinary evidence, and the burden of proof is on people (people without
medical training and clinical experience, let me remind you) who claim that
anyone can cure serious disease with a mere placebo effect.

The reply above prompted me to rewrite my original comment here (the comment
that is "grandfather" to this comment) as a FAQ file. I'll post that below.

Because the submitted article mentions the placebo effect, in the usual manner
of popular articles, perhaps I should share here some links that are helpful
for understanding what placebo effects are all about. Some of these online
links cite quite a few useful scholarly publications.

[http://www.sciencebasedmedicine.org/index.php/michael-
specte...](http://www.sciencebasedmedicine.org/index.php/michael-specter-on-
the-placebo-effect/)

"In other words, the best research we have strongly suggests that placebo
effects are illusions, not real physiological effects. The possible exception
to this are the subjective symptoms of pain and nausea, where the placebo
effects are highly variable and may be due to subjective reporting."

Despite the numerous press releases on the Web pointing to publications co-
authored by Ted Kaptchuk, who has NO medical training or credentials,

[http://www.sciencebasedmedicine.org/index.php/dummy-
medicine...](http://www.sciencebasedmedicine.org/index.php/dummy-medicine-
dummy-doctors-and-a-dummy-degree-part-2-0-harvard-medical-school-and-the-
curious-case-of-ted-kaptchuk-omd/)

[http://www.sciencebasedmedicine.org/index.php/dummy-
medicine...](http://www.sciencebasedmedicine.org/index.php/dummy-medicine-
dummy-doctors-and-a-dummy-degree-part-2-2-harvard-medical-school-and-the-
curious-case-of-ted-kaptchuk-omd-cont-again/)

the statements typically found in those articles, such as "Recent research
demonstrates that placebo effects are genuine psychobiological phenomenon
[sic] attributable to the overall therapeutic context, and that placebo
effects can be robust in both laboratory and clinical settings" are untrue.

[http://theness.com/neurologicablog/index.php/the-rise-and-
fa...](http://theness.com/neurologicablog/index.php/the-rise-and-fall-of-
placebo-medicine/)

"Despite the spin of the authors – these results put placebo medicine into
crystal clear perspective, and I think they are generalizable and consistent
with other placebo studies. For objective physiological outcomes, there is no
significant placebo effect. Placebos are no better than no treatment at all."

<http://www.ncbi.nlm.nih.gov/pubmed/20091554>

"We did not find that placebo interventions have important clinical effects in
general. However, in certain settings placebo interventions can influence
patient-reported outcomes, especially pain and nausea, though it is difficult
to distinguish patient-reported effects of placebo from biased reporting. The
effect on pain varied, even among trials with low risk of bias, from
negligible to clinically important. Variations in the effect of placebo were
partly explained by variations in how trials were conducted and how patients
were informed."

Fabrizio Benedetti, a co-author of one of the most cited papers who is also a
medical doctor, sums up his view this way: "I am a doctor, it is true, but I
am mainly a neurophysiologist, so I use the placebo response as a model to
understand how our brain works. I am not sure that in the future it will have
a clinical application."

[http://www.brainsciencepodcast.com/storage/transcripts/year-...](http://www.brainsciencepodcast.com/storage/transcripts/year-5/77-brainscience-
Benedetti.pdf)

To sum up, despite claims to the contrary by a person without medical training
who is often covered by the lay press, the best-considered view among medical
practitioners with clinical experience is that the placebo response has no
clinical application.

See also:

[http://www.sciencebasedmedicine.org/index.php/does-
thinking-...](http://www.sciencebasedmedicine.org/index.php/does-thinking-
make-it-so-cam-placebo-fantasy-versus-scientific-reality/)

<http://www.skepdic.com/placebo.html>

[http://www.sciencebasedmedicine.org/index.php/revisiting-
dan...](http://www.sciencebasedmedicine.org/index.php/revisiting-daniel-
moerman-and-placebo-effects/)

~~~
pella
> _"the best-considered view among medical practitioners with clinical
> experience is that the placebo response has no clinical application."_

see -> "open-hidden paradigm"

"Placebo Effects are Inherent in Clinical Practice – even when no placebo is
given

Some of the clearest evidence supporting the involvement of placebo effects in
clinical care comes in the form of the open-hidden paradigm (Figure 3). In
this experimental paradigm a treatment is given in a routine manner (the open
administration), where the psychosocial context surrounding treatment
administration is present, and a hidden manner, where the treatment is given
without the patient's knowledge. In the case of drug therapy, the open
administration mimics normal clinical care, where the doctor injects a drug in
full view of the patient with verbal and contextual interactions. In the
hidden administration, the drug is infused by a computer pump in the absence
of the clinician and the therapeutic context. Patients receiving hidden
administration are aware that at some stage they will receive a drug but they
do not experience the expectation component or other contextual factors
surrounding the administration. Because the hidden administration removes the
psychosocial context of treatment, this paradigm defines the placebo component
as the difference between open and hidden administrations, although no placebo
is given

The open-hidden paradigm has been used in several clinical settings.

In pain, hidden administrations of five commonly used painkillers (morphine,
buprenorphine, tramadol, ketorolac, metamizol) have been demonstrated to be
markedly less effective than open administrations. ..." ->
<http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2832199/>

------
lukevdp
"Evolution could explain the placebo effect"

Umm... what else could explain the placebo effect?

Evolution can explain every biological aspect ever to have existed if you take
it to a broad enough level

~~~
drcube
Not really. Evolution only explains the persistence of traits which influence
survival and reproduction. It can't explain why those traits arose in the
first place (random mutation), or the existence of traits which don't affect
survival or reproduction. It also can't explain why some traits never arose at
all (say, winged humans).

And to be really nitpicky, "evolution" is the observed fact that species
change over time. It isn't an explanation at all. Natural selection is the
explanation for evolution, both in general, and for specific traits.

~~~
sageikosa
Random mutation and natural selection. One's a generator, the other a filter.

------
vectorbunny
From the Nicholas Humphrey paper cited in the post:

"My view is this. The human capacity for responding to placebos is in fact not
necessarily adaptive in its own right (indeed it can sometimes even be
maladaptive). Instead, this capacity is an emergent property of something else
that is genuinely adaptive: namely, a specially designed procedure for
'economic resource management' that is, I believe, one of the key features of
the 'natural health-care service' which has evolved in ourselves and other
animals to help us deal throughout our lives with repeated bouts of sickness,
injury, and other threats to our well-being".

in full here: <http://www.humphrey.org.uk/papers/2002GreatExpectations.pdf>

------
jeffdavis
"I'm pleased to see that my theory stands up to computational modelling,"

Was anyone else disturbed by that statement?

We all know that models are heavily dependent on parameters, and by tweaking
them you can get whatever result you want. The only use a model has is when it
shows a pattern of predicting observations in the real world. In other words,
a model is essentially a theory about the way the world works.

So "stands up to computational modeling" strikes me as a very unscientific
thing to say -- kind of like saying "my theory stands up to his theory".
Theories should stand up against testing and observations in the real world.

~~~
aggronn
Without reading the context, I expect that 'computational modeling' refers to
a largely mathematical model that is potentially agnostic about underlying
causes. You can run simulations that accurately reflect the real world using
one set of variables, then run another model (or somehow test another model)
that confirms the original simulation's results from a different perspective;
ie, you have two theories, and you validate the second by proving its
equivalent to the first, even though it uses a different set of variables, or
looks at it using a different theoretical framework.

of course, you're right that this can be troublesome. just because you can
validate a theory as accurately modeling reality doesn't mean that the
components of the model are true or useful.

and necessarily, the first 'computational model' would have needed to be
already validated before something else might be validated against it...in
case that wasn't clear.

------
vannevar
FTA: _We subconsciously respond to treatment - even a sham one - because it
comes with assurances that it will weaken the infection, allowing our immune
response to succeed rapidly without straining the body's resources._

I wonder if there isn't an alternative explanation, that the placebo effect
may be an elaboration of the human social instinct. Consider how a control
patient in a drug trial must feel when they are not given any treatment.
Perhaps receiving the pill is an act of symbolic inclusion in the tribe that
cues the immune system that the individual has a better outlook because they
will be cared for by others.

~~~
maratd
> I wonder if there isn't an alternative explanation, that the placebo effect
> may be an elaboration of the human social instinct.

You read my mind. We're social animals. Hamsters may respond to sunlight,
human beings respond to communal support. We have plentiful food stores when
we are supported by our community and have none when we are abandoned. We're
not hamsters.

Somebody bothering to place you in a study, ask you dozens of questions, then
give you medicine ... at no cost to you ... doesn't that scream social
support?

~~~
SquareWheel
I wonder if a placebo would be just as effective if taken at home as a Tylenol
or similar.

------
syncerr
If we are to believe that triggering the full-force of the immune system is
some sort of switch, then perhaps it would be possible to synthesize a drug to
do this directly?

~~~
TheSOB88
According to the article, that drug is sugar in a gelcap...

------
username3
What can't evolution explain?

~~~
SquareWheel
Well, abiogenesis, for one.

