Placebo Effect by Ray Sahelian, M.D.
 

The placebo effect is a sort of "power of suggestion" response in which patients begin to feel better because they think they have received treatment rather than a placebo. These responses are usually short-term. For years, scientists have looked at the placebo effect as just a figment of overactive patient imaginations. Sure, placebo pills seemed to curb epileptic seizures, lower blood pressure, soothe migraines and smooth out jerky movements in Parkinson's — but these people weren't really better. Now, using PET scanners and MRIs to peer into the heads of patients who respond to placebo pills, researchers have discovered that the placebo effect is not "all in patient's heads" but rather, in their brains. New research shows that belief in a placebo treatment leads to changes in brain chemistry.

Placebo effect is real
There is a physiological component to the placebo effect. People who expect to get pain relief from a treatment show a greater release of dopamine in the part of the brain called the nucleus accumbens. In turn, they are more likely to report pain relief -- even though they receive a placebo. Dopamine is a chemical messenger and its activity in the nucleus accumbens is related to reward anticipation. The release of dopamine is necessary to spur the release of endorphins. Neuron, July 19, 2007.

   Anticipation of relief from a placebo can lead to an actual easing of aches, when the brain makes more of its own pain-dousing opiates. Brain scans of Parkinson’s patients show increases in a chemical messenger called dopamine, which leads to an improvement in symptoms when patients think — mistakenly — that they are receiving real therapy.

Placebo effect as pain medication
In a study by University of Michigan researchers, participants who were told they would receive painkillers showed increased production of endorphins — the brain's natural pain reliever — even though they got no analgesic at all. Most people can attest that the mere expectation of relief can somehow prompt the body to respond.

Placebo Pills and Depression
Studies in depressed patients have found that almost as many are helped by placebo treatments as by actual medications. In fact, as it turns out, a person’s response to placebo treatment may offer clues as to whether “real” treatments with antidepressants are likely to work.

It cannot be assumed that an antidepressant has lost its effectiveness if a patient relapses while continuing on the medication, because the medication may never have been effective in the first place and the patient may have been influenced by the placebo effect. Dr. Mark Zimmerman, director of outpatient psychiatry at Rhode Island Hospital discovered that the majority of relapses occur in patients who have never been true responders. In clinical practice, everyone is given an active medication, so it's not clear if a patient who responds has improved because of the medication or because of the placebo effect.

Brain waves may hold key
At the University of California at Los Angeles, placebo -treated volunteers were hooked up to an electroencephalograph (EEG), a device that records the brain’s electrical activity. After a week of placebo pills, the volunteers were then given either more placebos or an actual antidepressant. They weren’t told which type of pill they received. Eight weeks later, researchers scrutinized the brain waves recorded by the EEG back when all the volunteers were taking a placebo pill. The people who got the most benefit from the actual medication had a specific pattern of brain waves when they were being treated with placebos. Those results were described in a study published in the American Journal of Psychiatry. Researchers haven’t figured out yet what the specific pattern of brain waves mean, but the study does show how patients might be inexpensively screened with an EEG to show doctors who is most likely to respond to antidepressant medications.

Expensive placebo pills work better
Dan Ariely, a behavioral economist at Duke University in North Carolina, and colleagues at the Massachusetts Institute of Technology evaluated 82 volunteers. All got a light electric shock and were offered what they were told was a painkiller. Half were given a brochure describing the pill as a newly approved painkiller that cost $2.50 per dose and half were given a brochure describing it as marked down to 10 cents. Eighty-five percent of volunteers who thought they were getting a $2.50 pill said they felt less pain after taking it, compared with 61 percent of those who thought they were getting a discounted drug.