People may be more responsive to placebo drugs that they perceive to be "expensive" than to those with lower costs.
A new study of patients with Parkinson's disease found their perceptions of the cost of a drug significantly influenced their outcomes, the American Academy of Neurology reported.
"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," said study author Alberto J. Espay, of the University of Cincinnati in Ohio and a Fellow of the American Academy of Neurology. "We wanted to see if the people's perceptions of the cost of the drug they received would affect the placebo response."
The researchers looked at 12 patients with Parkinson's disease who were told they would be given shots of two formulations of the same drug; the second dose of which would be administered after the first wore off. They were told both formulations were believed to be equally effective, but one cost $100 per dose to manufacture and the other $1,500 per dose. What the patients were actually receiving was a saline placebo in both injections.
The researchers found when the study subjects received the "expensive" shot first their motor skills improved by 28 percent compared to when they received the "cheap" drug first.
"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 said.
The researchers noted the placebo effect could be more pronounced in Parkinson's patients because they have decreases the amount of dopamine in the brain, and the placebo effect is believed to increase the release of dopamine. A review board found the study's deception would have "no adverse effects on the rights or welfare of the participants."
"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 said. "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 findings were published in a recent edition of the journal Neurology.
