4. Introduction
• No one doubts—certainly not I—that the mind exercises
a powerful influence over the body.
• From the beginning of time, the sorcerer, the interpreter
of dreams, the fortune-teller, the charlatan, the quack,
the wild medicine-man, the educated physician, the
mesmerist, and the hypnotist have made use of the
client's imagination to help them in their work. They
have all recognized the potency and availability of that
force. Physicians cure many patients with a bread pill;
they know that where the disease is only a fancy, the
patient's confidence in the doctor will make the bread
pill effective.
• —Mark Twain
6. Introduction
• The placebo effect is a psychosomatic
phenomenon in which symptoms of a disease
or condition lessen — or even appear to be
cured completely — from the patient being
merely exposed to a treatment, as a result of
the body releasing endorphins
10. Introduction
• Believing that their condition will be improved, they
will begin to feel better and perhaps identifiable
symptoms may disappear, irrespective of whether
the treatment has any chemical or pharmacological
effect. Because of this, controlling for the placebo
effect is an essential part of medicine.
• For example, sugar pills or saline solutions, which
have no pharmacological properties, are commonly
prescribed as placebo treatments to control for the
effect the simple act of intervening in a patient's illness.
14. Introduction
• Most alternative medicine is suggested to work
through this method — mostly because any
treatment that doesn't work through this
method is labelled "medicine".
• Under placebo control, alternative
medicines do not perform significantly
better.
18. Causes
• The placebo effect is quite a complex
phenomenon.
• It is influenced by a multitude of things,
including positive thought, reduced stress,
the intensity or "drama" of the medical
intervention, a patient's expectations of
what the treatment can do, and the wider
cultural meaning of medical treatment.
20. Causes
• A particularly interesting observation is
how much these factors can be influenced
subconsciously; a doctor merely telling
someone a treatment will work may not
produce such a dramatic effect if the doctor
doesn't actually believe it too.
22. Causes
• Because of the complexity of issues
surrounding what causes a sick patient to get
"better", it's difficult to say if an individual
was cured by a placebo effect, real treatment,
regression to the mean or a complicated
combination of all three.
24. Causes
• So, the placebo effect is best described as a
statistical phenomenon, where prognosis
improves for a certain percentage of
patients simply exposed to a treatment of
some kind.
26. Causes
• However, as the placebo effect is powered by
belief in a treatment and exposure to it, it can
manifest in individuals to a certain extent.
• A homeopathic prescription of water
containing a minute dilution of powdered
oyster shell may bring some improvement to
a patient who has total faith in the
homeopathic method.
28. Placebo Effect
• A patient who is sceptical of homeopathy may
experience a reduced effect or no effect at all,
as demonstrated by James Randi when he
regularly consumes massive overdoses of
homeopathic sleeping pills on stage.
• If these two hypothetical patients begin to feel
better anyway, the former would be likely to
attribute it to the treatment while the latter would
be likely to dismiss it as just feeling better
anyway.
29. Why didn't homeopathic sleeping pills
work on James Randi's body?
Because homeopathy doesn't work.
It does not work on his body, or
anybody else's because it cannot
work.
30. James Randi: Homeopathy, quackery
and fraud
• Legendary skeptic James Randi takes a fatal dose of
homeopathic sleeping pills onstage, kicking off a searing
18-minute indictment of irrational beliefs.
• https://www.ted.com/talks/james_randi?language=en&utm_campaig
n=tedspread&utm_medium=referral&utm_source=tedcomshare
31. Expectation effects
• When I was a boy a farmer's wife who lived five
miles from our village had great fame as a faith-
doctor — that was what she called herself.
• Sufferers came to her from all around, and she laid her
hand upon them and said, "Have faith—it is all that is
necessary," and they went away well of their ailments.
She was not a religious woman, and pretended to no
occult powers. She said that the patient's faith in her did
the work.
• Several times I saw her make immediate cures of
severe toothaches. My mother was the patient.
—Mark Twain
35. Expectation effects
• Expectations of what drugs and medical
treatments can, and do, change over time.
Often the efficacy of real drugs decreases when
a new version is released, as people expect the
new one to be better. New treatments, which are
perceived to be more effective because they
exploit new technologies induce a placebo effect
in addition to their real effect and, sometimes, this
can lead to an overestimate of their real efficacy
over an existing treatment.
37. Expectation effects
• This is why in controlled studies of new
treatments, they are compared not with
inactive placebos but the best effective
treatment available and the experience
between patients is minimised so that they
genuinely cannot tell the difference between
treatment A and treatment B.
39. Expectation effects
• It is an observed phenomenon that placebo
drugs distributed in flashier packaging tend to
produce a stronger reaction than their plain
packaging counterparts.
• There is also evidence that the placebo effect can
work even if the person knows that it is a placebo,
as observed in a study of patients with irritable
bowel syndrome (IBS).
• In short, the placebo effect works if you expect
the placebo effect to work.
40. The Power of Drug Color
A pill's hue can affect how it's judged by patients, how it's
marketed, and even how well it works.
43. Ethical considerations
• There are a number of ethical issues
surrounding the wilful use of placebos as a
treatment — known as placebopathy.
• Many casual complaints can be dealt with by
inactive placebo treatments (involving a sugar
pill and a reassuring visit to a doctor) and this
would save a significant amount of time,
money and lowers the risk of drug dependency
and overdose.
45. Placebopathy
• Yet, despite these potential benefits to willingly
issuing placebos, it is not considered ethical in
modern medicine.
• Firstly, placebopathy involves medical professions
deceiving their patients, which is considered bad ethical
practice, and secondly there is a risk in delaying the
treatment of a real condition due to a doctor mistrusting
or underestimating their patient's symptoms.
• If a patient complaining of a headache is given a
sugar pill to placate it, and it turns out to be a
serious condition that requires non-placebo
treatment then at the very least this would be a
serious lawsuit waiting to happen.
47. .
Use In Medical Trials
• Because the placebo effect is so powerful, efficacy claims
for medical treatments must be tested in an experiment
that controls for this effect. This is usually achieved by
running a double-blind test, where some patients receive
the treatment being examined, and others get a placebo.
• Neither the patients or the administrators of the treatment
know who is in which group. In order for the treatment to
be proved useful, it must produce results that are better than
the placebo at a statistically significant level. In practice the
"placebo" is usually an existing treatment, as being better
than an placebo isn't enough — a new treatment has to be
better than the existing one!
50. The strangeness of the placebo effect
• The power of the placebo effect produces
many strange and interesting quirks.
• These indicate that the placebo effect may
well be more than mere "mind over
matter", and stem from what is known as a
complex intervention.
51. The strangeness of the placebo effect
• The effect has been observed in animals and
babies. However, in practice this requires
conditioning first, which is analogous to just
telling someone a treatment will work when
you can't communicate more directly.
53. The strangeness of the placebo effect
• Placebos that are "more expensive" work
better.
• The effect shows a dose-response
relationship like a real medical intervention;
two pills are more effective than one
55. The strangeness of the placebo effect
• More dramatic placebos are more effective.
Injections work better than pills.
• A full consultation session with a doctor
prior to a placebo is more effective than just
giving a patient a pill dismissively.
57. The strangeness of the placebo effect
• The placebo effect may possibly have the
ability to overpower real pharmacological
effects.
• People who were given very strong drugs to
induce nausea didn't develop symptoms as
they were told the treatment would actually
relieve nausea.
60. The strangeness of the placebo effect
• The placebo effect may be transferable; a
patient being around someone who believes
that the treatment will work can cause the
patient to do better — even if that person is
a doctor
62. Nocebo effect
• The placebo effect has a somewhat less well-
known, slightly evil cousin; the nocebo effect.
This occurs when an individual's expectation
of negative effects generates or aggravates
those effects
65. Nocebo effect
• For ethical reasons the nocebo effect has not been well
studied directly, but it is probably behind the witch
doctor's ability to cause illness in those people he curses.
• It has also been used to explain unusual phenomenon like the
culture-bound syndrome SUNDS (Sudden Unexpected
Nocturnal Death Syndrome) in immigrants from the
Hmong people of Laos; belief in angry supernatural
forces combined with the phenomenon of sleep paralysis
to convince sufferers that they were under attack, leading
to extremely high levels of stress which could trigger
dormant heart defects.
• As a side note, these same deaths were what inspired film
director Wes Craven to create the fictional dream-using serial
killer Freddy Krueger.
67. Terminology
• Big Placebo
• Big Placebo is a nickname given to alternative
medicine companies, coined as a counterpart
to the name Big Pharma for drug companies.
The term was coined by Lindsay Beyerstein in
2009
69. Terminology
• Folk Remedy
• A folk remedy is any purported health remedy
which comes from a pre-scientific source, usually
through oral tradition.
• They remain popular among people who continue
to use them because it is popular in the culture
they are from or because "this is what grandma
did", but many such practices have also remained
in use through promotion as patent medicines or
alternative medicine fads
71. Terminology
• Faith healing
• Faith healing is a form of medical woo that
attempts to cure a wide range of ailments
primarily through personal prayer and
intercessory prayer, sometimes augmented by
faith-based rituals. God is capable of curing all
diseases and injuries that could ever affect
anybody, assuming He is willing.
73. Case Study
• A fascinating landmark study of placebo
surgery for knee osteoarthritis
• Moseley JB, O’Malley K, Petersen NJ, et al. A
controlled trial of arthroscopic surgery for
osteoarthritis of the knee. N Engl J Med. 2002
Jul 11;347(2):81–8
75. Case Study
• In this landmark and fascinating study, people with
osteoarthritis improved equally well regardless of
whether they received a real surgical procedure or a
sham, which is a particularly striking example of the
placebo effect and implies that belief can have an effect
even on a “mechanical” knee problem.
• From the abstract: “In this controlled trial involving
patients with osteoarthritis of the knee, the
outcomes after arthroscopic lavage or arthroscopic
debridement were no better than those after a
placebo procedure.”
76. In this controlled trial involving patients with osteoarthritis of the knee,
the outcomes after arthroscopic lavage or arthroscopic debridement were
no better than those after a placebo procedure
77. Case Study
• In 2008, these findings were fully supported by
a Cochrane Collaboration review
(Laupattarakasem) which concluded that
“there is ‘gold’ level evidence that arthroscopic
debridement has no benefit,” and by New
England Journal of Medicine (Kirkley) which
reported that “surgery for osteoarthritis of the
knee provides no additional benefit to
optimized physical and medical therapy.”
78. BBC Documentary - Placebo Effect As Good As
Surgery For Outcome In Knee Pain.
https://youtu.be/HqGSeFOUsLI
79. Case Study
• This study inspired more comparisons of
orthopedic surgeries to shams. By 2016, at
least four more popular surgeries have been
shown to have no benefit (Louw 2016).
• ~ Paul Ingraham
80. BBC Documentary - Placebo Effect As Good
As Surgery For Outcome In Knee Pain.
81. Case Study: The Ethics of Homeopathy
• Journal Bioethics, examines the ethics of
placebos, based on an analysis of
homeopathy.
• Homeopathy is the ultimate placebo in routine
use — most remedies contain only sugar and
water, lacking a single molecule of any
potentially medicinal ingredient
83. Case Study: The Ethics of
Homeopathy
• concise summary of the scientific absurdity of
homeopathy.
• Hahnemann’s “Law of Similars”, based on a single
observation of the effects of quinine on malaria, is the
basis for the non-scientific process of “provings” to
match symptoms to substances.
• The results of provings are compiled in the
Homeopathic Materia Medica, which homeopaths
select their remedies from. (So now we have
remedies based on products including “sleep”,
Stonehenge, shipwrecks, ascending colons, light
bulbs, and vacuum cleaner dirt.)
87. Case Study: The Ethics of
Homeopathy
• Hahnemann’s second law, the “Law of
Infinitesimals” is as absurd as the law of
similars.
• That a product can gain potency and effect
with dilution, and that effect persists (and
even grows stronger) even after being
diluted completely away defies physical
laws.
92. Case Study: The Ethics of
Homeopathy
• The research on homeopathy.
• Given its premise is implausible (or
impossible), it is not surprising that the
highest quality clinical trials have
demonstrated no efficacy beyond placebo
effects.
94. Case Study: The Ethics of
Homeopathy
• So it’s implausible, the remedies contain no
medicinal ingredients, and, not surprisingly,
it works no better than a placebo. Yet it is
popular, even among some physicians and
scientists
96. Waste of Resources
• If you’ve never bought it before,
homeopathy is not cheap: its prices are
comparable to conventional products with
active ingredients. Given the lack of efficacy,
every dollar spent on homeopathy is a waste of
resources
97. Credibility Issues
• Most consumers expect the products on
pharmacy shelves to contain medicinal
ingredients, and to have some sort of evidence
to support their sale.
• If I substituted placebos for prescription
drugs, I’d quickly lose my license to practice
100. References
• A fascinating landmark study of placebo surgery for knee osteoarthritis
• https://www.painscience.com/biblio/fascinating-landmark-study-of-placebo-surgery-for-
knee-osteoarthritis.html
• Is the Nocebo Effect Hurting Your Health?
• https://www.webmd.com/balance/features/is-the-nocebo-effect-hurting-your-health#1
• Nocebo
• https://en.wikipedia.org/wiki/Nocebo
• Placebos as Medicine: The Ethics of Homeopathy
• https://sciencebasedmedicine.org/placebos-as-medicine-the-ethics-of-homeopathy/
• Placebo
• https://en.wikipedia.org/wiki/Placebo
• Placebo Effects in Medicine
• https://www.nejm.org/doi/full/10.1056/nejmp1504023
• The placebo effect and homeopathy.
• https://www.ncbi.nlm.nih.gov/pubmed/20471615
• What Is the Placebo Effect?
• https://www.webmd.com/pain-management/what-is-the-placebo-effect#1
