CINCINNATI—People’s perceptions of the cost of a drug may affect
how much they benefit from the drug, even when they are receiving only a
placebo, according to new research from the University of Cincinnati (UC).
Alberto Espay, MD, an
associate professor in the UC Department of Neurology and Rehabilitation
Medicine and director and endowed chair of the James J. and Joan A. Gardner
Center for Parkinson’s Disease and Movement Disorders at the UC Neuroscience
Institute, describes the findings in the Jan. 28 online issue of Neurology, the medical journal of the American Academy of
Neurology (AAN). Espay is an AAN
"Patients’ expectations play
an important role in the effectiveness of their treatments, and the placebo
effect has been well documented, especially in people with Parkinson’s
disease,” Espay says. "We wanted to see if the people’s perceptions of
the cost of the drug they received would affect the placebo response.”
For the study, 12 people with Parkinson’s disease were told
that they would receive shots of two formulations of the same drug, with the
second shot given after the first shot wore off. They were told that the
formulations were believed to be of similar effectiveness, but that they
differed in manufacturing cost—$100 per dose versus $1,500 per dose.
Participants were told that the study was intended to prove that the drugs,
while priced differently, were equally effective.
In reality, the participants received only a saline solution
for both injections, but were told they were receiving either the "cheap” or
"expensive” drug first. Before and after each shot, participants took several
tests to measure their motor skills and also had brain scans to measure brain
Both placebos improved motor function compared with their
respective baseline. But when people received the "expensive” drug first, their
motor skills improved by as much as 28 percent as opposed to 13 percent on the
same test when they received the "cheap” drug.
"If we can find strategies to harness the placebo response to
enhance the benefits of treatments, we could potentially maximize the benefit
of treatment while reducing the dosage of drugs needed and possibly reducing
side effects,” Espay says.
Espay says the placebo response might be stronger in people
with Parkinson’s because the disease decreases the amount of dopamine in the brain
and the placebo effect is known to increase the release of brain dopamine.
Dopamine affects movement, but it also affects anticipation, motivation and
response to new things.
"People who receive the shots thinking they received a drug
may have an ‘expectation of reward’ response, which is associated with the
release of dopamine similar to the response to the reward itself,” Espay says.
The study received extra scrutiny from UC’s Institutional
Review Board before it began because it involved intentional deception of the
participants. The review board found that the study complied with federal
research regulations that allow waiver of the informed consent requirement and
that the deception would have no adverse effects on the rights or welfare of the
After the study, the participants were told about the true
nature of the study. "Eight of the participants said they did have greater
expectations of the "expensive” drug and were amazed at the extent of the
difference brought about by their expectations,” Espay says. "Interestingly,
the other four participants said they had no expectation of greater benefits of
the more expensive drug, and they also showed little overall changes.”
The study was supported by the Davis Phinney
Foundation for Parkinson’s.