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 Fellow.
“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 activity.
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 participants.
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.