Research is showing the power of expectations, that they have physical — not just psychological — effects on your health. Scientists can measure the resulting changes in the brain, from the release of natural painkilling chemicals to alterations in how neurons fire.
Among the most provocative findings: New research suggests that once Alzheimer's disease robs someone of the ability to expect that a proven painkiller will help them, it doesn't work nearly as well.
It's a new spin on the so-called placebo effect — and it begs the question of how to harness this power and thus enhance treatment benefits for patients.
"Your expectations can have profound impacts on your brain and your health," says Columbia University neuroscientist Tor Wager.
"There is not a single placebo effect, but many placebo effects," that differ by illness, adds Dr. Fabrizio Benedetti of Italy's University of Torino Medical School, who is studying those effects in patients with Alzheimer's, Parkinson's disease and pain.
The placebo effect is infamous from studies of new medications: Scientists often given either an experimental drug or a dummy pill to patients and see how they fare. Frequently, those taking the fake feel better, too, for a while, making it more difficult to tease out the medication's true effects.
Doctors have long thought the placebo effect was psychological.
Now scientists are amassing the first direct evidence that the placebo effect actually is physical, and that expecting benefit can trigger the same neurological pathways of healing as real medication does. Among them:
University of Michigan scientists injected the jaws of healthy young men with salt water to cause painful pressure, while PET scans measured the impact in their brains. During one scan, the men were told they were getting a pain reliever, actually a placebo.
Their brains immediately released more endorphins — chemicals that act as natural painkillers by blocking the transmission of pain signals between nerve cells — and the men felt better.
To return to pre-placebo pain levels, scientists had to increase the salt-water pressure.