Placebo Effect Is Not Just Psychological

Patients who believe in the effectiveness of theirto 100. After each scan, the researchers asked
pain medication will experience greater pain relief,the participants more questions about their mood,
finds a University of Michigan study published inemotions and other aspects of how they felt
the Journal of Neuroscience. Just thinking that aduring the scans.
medicine will relieve pain is enough to prompt theThere were significant differences between
brain to release its own natural painkillers, resultsratings given by participants after the scan in
indicate.which they received the placebo compared to the
The study, funded by the National Institutes ofscan during which they received the jaw injection
Health, provides the first concrete evidence thatalone.
endorphins, the brain's own pain-fighting chemicals,"We were able to see that the endorphin system
play a direct role in the phenomenon known aswas activated in pain-related areas of the brain
the "placebo effect."and that activity increased when someone was
Endorphins behave similarly to opiate drugs, suchtold they were receiving a medicine to ease their
as heroin and morphine. They bind to receptorspain. They then reported feeling less pain. The
and stop the transmission of pain signals along themind-body connection is quite clear," reports
nerve pathways. Previous studies have shownZubieta.
that the brain responds physically during theSuggestion Triggers Endorphin Release
placebo effect, but the new study is the first toAnother scan was performed in which subjects
pinpoint a specific mechanism that triggers thewere administered additional placebo prior to
brain's physical response.increased pain-induction to discern whether
"This deals another serious blow to the idea thatendorphin activity could be stimulated solely by
the placebo effect is a purely psychological, notsuggestion.
physical, phenomenon," says lead author Jon-KarAs additional placebo was administered, endorphin
Zubieta, MD, PhD, associate professor ofactivity increased. Researchers then had to
psychiatry and radiology at the U-M Medical Schoolincrease the amount of salt-water in order to
and associate research scientist at the Molecularmaintain the subjects' pain levels, which they did
and Behavioral Neurosciences Institute.without their knowledge.
The study involved 14 young men who agreed toTwo-thirds of the study participants were
allow researchers to inject their jaw muscles withclassified as "high placebo responders,"
a concentrated salt-water solution to induce pain.experiencing significant endorphin activity through
Brain scans were performed on the subjects tothe power of suggestion. This helps explain why
monitor the activity of their brains' naturalso many people report relief after receiving
painkilling endorphins during the process.therapies and remedies that provide no actual
Mind-Body Connection Clearphysical benefit.
During one scan, they were told they wouldThis new information may lead to better use of
receive a medicine (in fact, a placebo) that mightcognitive, or psychological, therapy for people with
relieve pain. Subjects reported a lessening of painchronic pain, the authors suggest.
after receiving the placebo, and brain scansResearchers used positron emission tomography
indicated increased endorphin activity in four areas(PET) scans to determine exactly which part of
of the brain known to be involved in the responsethe brain the endorphin activity originated from,
to, and processing of, pain.cross-registering them with magnetic resonance
Every fifteen seconds, the subjects were askedimaging (MRI) scans for the purposes of accuracy.
to rate the intensity of their pain on a scale of 0