August 23, 2005
Study Finds Placebo Effect Has Scientific BasisTopics: Medicine
In the first concrete evidence that endorphins, the brain's own pain-fighting chemicals, play a direct role in the phenomenon known as the placebo effect, results from a study by researchers at the University of Michigan shows that patients who believe in the effectiveness of their pain medication will experience greater pain relief. In other words, just thinking that a medicine will relieve pain is enough to prompt the brain to release its own natural painkillers.
Endorphins behave similarly to opiate drugs, such as heroin and morphine. They bind to receptors and stop the transmission of pain signals along the nerve pathways. Previous studies have indicated that the brain responds physically during the placebo effect, but the new study is the first to pinpoint a specific mechanism that triggers the brain's physical response.The researchers used positron emission tomography (PET) scans to determine exactly which part of the brain the endorphin activity originated from, and cross-registered them with magnetic resonance imaging (MRI) scans, to ensure the accuracy of the measurements.
"This deals another serious blow to the idea that the placebo effect is a purely psychological, not physical, phenomenon," says lead author Jon-Kar Zubieta, MD, PhD, associate professor of psychiatry and radiology at the U-M Medical School and associate research scientist at the Molecular and Behavioral Neurosciences Institute.
Posted by Richard at August 23, 2005 7:02 PM
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