The Placebo Effect
Key: AWL to Study, Low-frequency Vocabulary
What is the placebo effect?
The Placebo Effect
• Refers to an improvement in symptoms as a result of
medical treatment with an inactive substance or
staged medical procedure.
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patient recovers without genuine medical intervention
attributed to belief in the effectiveness of treatment
belief mediates healing of symptoms
cases reported since the early 20th century
Explain how the placebo effect works.
Dramatic Example: Knee Surgery
• Doctor conducted controlled experiment on three
groups of patients with knee pain.
 first group: shaved off thin layers of damaged cartilage
 second group: flushed out
the knee joint and
disposed of unhealthy
tissue
What do you think the doctor did with the third group?
Third Group
• The surgeon simulated surgery
by anesthetizing patients and
making incisions.
• No knee surgery was performed.
• Patients were informed of
staged operations two years
later.
Do you think that this experiment was ethical?
Why or why not?
Results
• Knee pain diminished significantly in all three groups.
 no difference in the level of
pain decrease in any one group
 uniform results mediated by
the placebo effect
What is your opinion of these amazing results?
Placebo Patient
• Quoted as saying: “Anything is possible when you put
your mind to it.”
Do you agree with this statement? Why or why not?
Research on Other Diseases
• Depression is an area of
major interest:
 recent increase in use of
antidepressants
 critics claim that the
$9.6 billion industry is making
profit on pills no more
effective than placebos
Do you think doctors today overprescribe medication?
Antidepressant Study
• Psychology professor at University of Connecticut
obtained hard data on clinical studies of six major
antidepressants.
• Concluded:
 80% of the effectiveness
of antidepressants was
due to the placebo effect.
What is your opinion of the antidepressant industry?
Neuroscience
• Neuroscientists have technology to determine the
brain mechanisms responsible
for the placebo effect.
 Brain imaging techniques record
events instigated by anticipation
of symptom relief.
 The body’s own pain relief center
releases chemical to ease pain.
Why does the body have its own pain relief center?
Other Studies
• Parkinson’s disease: dopamine deficiency is a factor
 Patients release dopamine upon ingesting a placebo.
Why do patients need placebos to instigate the placebo
effect if it is their own brains that do all the work?
The Body’s Capacity to Heal
• Researchers conclude that the body has innate healing
capacity.
 invoked through the power of belief
What other problems could you solve with
the power of belief?
Up Until This Point…
• Doctors have invested therapeutic effort in drugs and
surgery.
 effective way in which to increase incomes
Do you think more energy should be put into exploring
the less invasive biology of belief?