Brain's Release of Endorphins Causes Placeo Effect

New research suggests that placebos work because your belief system tells your brain to block the pain or discomfort. In the study, researchers found that when patients expect a treatment to be effective, the brain area responsible for pain control is activated, causing the release of natural endorphins.

These endorphins then send a cascade of instructions down to the spinal cord to suppress incoming pain signals and patients feel better, regardless of whether the treatment ~ a pill or some other medical intervention ~ had any authentic direct effect.

According to the London Times:

The sequence of events in the brain closely mirrors the way opioid drugs, such as morphine, work ~ adding weight to the view that the placebo effect is grounded in physiology.

The finding strengthens the argument that many established medical treatments derive part of their effectiveness from the patients’ expectation that the drugs will make them better.

The latest studies on antidepressants suggest that at least 75 per cent of the benefit comes from the placebo effect. GPs also observe that patients report feeling better only days after being prescribed antidepressants, even though the direct effects take several weeks to kick in.

In the study, published this week in the journal Science, the spinal cords of 15 healthy volunteers were scanned using functional magnetic resonance imaging (MRI). The scan examined the dorsal horn, which transmits pain signals coming up through the spinal cord into the pain-related areas in the brain.

During the scan, the volunteers received laser “pinpricks” to their hands. The volunteers were told that a pain-relief cream had been applied to one of their hands and a control cream to the other. But unknown to the volunteers, an identical control cream was administered to both hands.

When people believed that they had received the active cream, they reported feeling 25 per cent less pain and showed significantly reduced activity in the spinal cord pathway that processes pain.

“We’ve shown that psychological factors can influence pain at the earliest stage of the central nervous system, in a similar way to drugs like morphine,” said Falk Eippert, of the University Medical Centre Hamburg-Eppendorf, who led the study.

Click here for the London Times article.