Researchers Demonstrate How Placebo Effect Works in the Brain

July 30, 2007
Researchers Demonstrate How Placebo Effect Works in the Brain
Pain pathways in motion in the brain during the placebo effiect. Credit: Columbia University

Columbia University scientists, with colleagues from the University of Michigan, have shown how the neurochemistry of the placebo effect can relieve pain in humans. The scientists found that the placebo effect caused the brains of test volunteers to release more of a natural painkiller.

The placebo effect is an improvement in a medical condition caused by a patient’s belief as opposed to actual treatment. Exactly how the positive expectations created by placebos translate into pain relief had been a mystery until now.

Understanding how placebo effects work may give scientists insight into why many drugs have a range of effects on people, how drugs and other treatments work together with psychological states, and how psychology can be effectively used in treatment.

The research team was led by Tor Wager, Columbia professor of psychology. “Placebo effects are often observed in clinical practice, but there have been relatively few scientific studies that document the kinds of diseases that can be influenced by placebo treatments and how the treatments work in the brain and body,” Wager said.

“Yet, placebo groups are included in virtually every major clinical trial, which is a testament to their importance. Only in the past few years have scientists developed the tools to directly investigate how placebos work in the human brain.”

In the experiment, scientists applied a placebo cream to volunteers’ forearms; volunteers were told it was a pain reliever, though the cream was not. Next, a control cream was applied to a nearby area, and subjects were told it had no effect. Researchers then placed a painfully hot stimulus (similar to a very hot cup of coffee) to both forearm areas and used positron emission tomography (PET) scans to measure and compare brain activity during each application. They found that the placebo treatment caused the brain to release more opioids, a chemical produced by the body and released by the brain, to relieve pain.

The scientists discovered that in the first area treated with a placebo, which volunteers falsely believed to have been treated with a pain reliever, opioid release occurred in brain areas associated with pain relief—in particular, the periadqeductal gray, an area in the brainstem used in neurosurgical interventions to control chronic pain. They also found opioid release in the orbitofrontal cortex and anterior cingulate, parts of the cerebral cortex thought to be related to evaluating and orchestrating responses in the brain and body to deal with a perceived threat—producing, for example, the so-called flight-or-fight response.

“These results extend our knowledge of how beliefs and expectations affect the brain's neurochemistry and show that one's mental response to a challenge can affect the brain and body in ways that are relevant to health,” Wager explained. “Understanding these interactions can pave the way for new treatments that are informed by knowledge of mind-body interactions.”

Source: Columbia University

Explore further: World-first ketamine trial shows promise for geriatric depression

Related Stories

World-first ketamine trial shows promise for geriatric depression

July 24, 2017
Australian researchers have completed the world's first randomised control trial (RCT) assessing the efficacy and safety of ketamine as a treatment for depression in elderly patients.

The brain and the gut talk to each other—how fixing one could help the other

July 17, 2017
It's widely recognised that emotions can directly affect stomach function. As early as 1915, influential physiologist Walter Cannon noted that stomach functions are changed in animals when frightened. The same is true for ...

Controlled temperature change inside ear can prevent migraines

July 6, 2017
The application of gentle cooling and warming currents inside the ear canal can provide relief for migraine sufferers, new research at the University of Kent has helped show.

Can trusting your doctor help reduce pain?

May 4, 2017
Getting a shot at your doctor's office can be a stressful experience. But what if you knew your doctor was from your hometown, liked the same food as you, or shared your religious beliefs? Now that you feel more culturally ...

First randomized controlled trial of DBS for chronic pain shows promise

June 20, 2017
Deep brain stimulation (DBS) of the ventral striatum/anterior limb of the internal capsule is safe and feasible in addressing the affective component of pain in patients with post-stroke pain syndrome.

Cannabis reverses aging processes in the brain

May 8, 2017
Memory performance decreases with increasing age. Cannabis can reverse these ageing processes in the brain. This was shown in mice by scientists at the University of Bonn with their colleagues at The Hebrew University of ...

Recommended for you

Talking to yourself can help you control stressful emotions

July 26, 2017
The simple act of silently talking to yourself in the third person during stressful times may help you control emotions without any additional mental effort than what you would use for first-person self-talk – the way people ...

Heart rate study tests emotional impact of Shakespeare

July 26, 2017
In a world where on-screen violence has become commonplace, Britain's Royal Shakespeare Company is turning to science to discover whether the playwright can still make our hearts race more than 400 years on.

Do all people experience similar near-death-experiences?

July 26, 2017
No one really knows what happens when we die, but many people have stories to tell about what they experienced while being close to death. People who have had a near-death-experience usually report very rich and detailed ...

Risk for bipolar disorder associated with faster aging

July 26, 2017
New King's College London research suggests that people with a family history of bipolar disorder may 'age' more rapidly than those without a history of the disease.

Visual clues we use during walking and when we use them

July 25, 2017
(Medical Xpress)—A trio of researchers with the University of Texas and Rensselaer Polytechnic Institute has discovered which phase of visual information processing during human walking is used most to guide the feet accurately. ...

Toddlers begin learning rules of reading, writing at very early age, study finds

July 25, 2017
Even the proudest of parents may struggle to find some semblance of meaning behind the seemingly random mish-mash of letters that often emerge from a toddler's first scribbled and scrawled attempts at putting words on paper.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.