Placebos work because patients expect them to work, and the circuits of the brain obligingly follow suit. That's been well established when it comes to physical pain. Now, according to a new study published in Neuron, researchers in Sweden have found that placebos can also alleviate psychological distress.

In a two-day experiment, 15 volunteers were asked to rate their reactions to disturbing pictures, such as images of mutilated bodies. They were told they would initially be given an anti-anxiety drug to reduce distress caused by the pictures might cause, and then be given an antidote that would block the soothing effects of the first drug and restore the full impact of the photos. Before-and-after MRI brain scans confirmed the effectiveness of the anti-anxiety drug in softening unpleasant perceptions.

When the exercise was repeated the following day, however,  the anti-anxiety drug the subjects were told they were receiving was actually a placebo. The second day's before-and-after MRI scans showed that the placebo was still effective in reducing the subjects' distress when viewing the pictures. Clearly the persuasive power of the mind matters, whether in response to physical or emotional discomfort.

From our archive:
03/01/2004  Picturing the Placebo Effect