June 16, 2005
Placebos Can Bring Emotional Relief, Too
Brain scan study shows they affect neurological pain centers
HealthDay News -- Experts have long noted the "placebo effect" -- that a sham pill can bring about real pain relief or symptom improvement. Now, a new study finds that placebos may bring emotional relief to people, too.
Reporting in the June 16 issue of the journal Neuron, Swedish researchers at the Karolinska Institute in Stockholm said a placebo reduces anxiety by affecting the same basic brain circuitry involved in the relief of pain.
In this study, volunteers were shown unpleasant pictures -- for example, photos of mutilated bodies -- and were then given a real anti-anxiety drug, which the researchers said would reduce their unpleasant perceptions of the pictures.
The volunteers were subsequently given an antidote to the anti-anxiety drug and told that this would restore their unpleasant perceptions.
In tests the following day, the volunteers were told they would be given the same drugs. However, instead of the anti-anxiety drug they received a saline solution as a placebo. At the same time, their brain activity was scanned using real-time functional magnetic resonance imaging (fMRI) while they viewed the unpleasant pictures.
According to the researchers, the volunteers' ratings of the unpleasant pictures were reduced by about 29 percent after taking the placebo, while the fMRI scans showed lowered activity in their brains' emotional centers.
The volunteers who showed the greatest reduction of activity in this emotional center had the largest decrease in their ratings of the unpleasant pictures.
"The present data demonstrate that emotional experience may be modulated through a placebo treatment in a similar manner as has been previously reported for pain perception," the study authors wrote.
The University of Michigan Health System has more about placebo treatment and pain.