New Study on Placebo Effect Prompts Look at Power of Belief

doctors' attitudes towards treatments may influence placebo effects

By Jonny Lupsha, Wondrium Staff Writer

A new study published in the scientific journal Nature shows that the placebo effect can be influenced by doctors. Patients can pick up on their physicians’ attitudes towards a treatment and that subconscious awareness can affect the treatment’s success. It adds a new page to the story of medical mind over matter.

Doctor giving medical advice to patient
Patients often experience greater relief from symptoms when they believe their doctors have shown confidence that the treatment will work. Photo by Andrei_R / Shutterstock

According to the study, researchers “systematically manipulated providers’ expectations in a simulated clinical interaction involving administration of thermal pain and found that patients’ subjective experiences of pain were directly modulated by providers’ expectations of treatment success, as reflected in the patients’ subjective ratings, skin conductance responses, and facial expression behaviors.”

In other words, the researchers assigned test subjects random roles as a “doctor” or “patient” and told the “doctors” to administer different topical creams to patients who had been exposed to thermal pain. Some doctors were told their creams were special pain-relieving creams and others were told their creams had no medicinal value. In reality, all creams were an identical petroleum-based jelly with no real medicinal value. However, patients receiving the petroleum jelly from doctors who believed the jelly was a new pain-relieving medicine reported lower levels of pain due to the doctors’ exhibited attitudes towards the treatment.

The study is only the second of its kind, despite the researchers’ claims that the theory—that doctors’ attitudes towards a treatment can provide a placebo effect—date back to the 1930s. The patient side of the placebo effect, on the other hand, is well-documented.

What Placebos Are

“Placebos are usually inactive substances—things like sugar or starch pills that are given to people with some suggestion that they might help,” said Dr. Ronald D. Siegel, Assistant Clinical Professor of Psychology at Harvard Medical School/Cambridge Health Alliance.

For some reason, they work. The power of suggestion—that a pill will help alleviate some symptom of illness—often tricks the brain into believing that the treatment is helping. Even more powerful than the inactive placebos are “active placebos.”

“An active placebo isn’t just sugar or starch; it’s some medicine that in some way causes some response in the body which is uncomfortable,” Dr. Siegel said. “It’s like giving somebody niacin that will make them flush, or giving them something that will give them a dry mouth—something so that the person can feel a change in the body, even if that change in the body has nothing to do with the purported effect of the placebo.”

The Proof Is in the Pudding

Maybe the most startling placebo effect comes from sham heart surgery. Patients would complain of experiencing angina pain, which Dr. Siegel defined as “pain that comes from partial or greater occlusion of blood vessels in and around the heart.” Doctors would perform open heart surgery on the patients and tie off a certain artery in the chest, believing it would cause the body to create other blood vessels called “collateral vessels” to bypass the artery that had been sewn shut.

“It used to work pretty well,” Dr. Siegel said. “They got 80 percent to 90 percent success rate of people recovering from angina pain with the surgery. The only fly in the ointment was that every once in a while, somebody would subsequently die and would have an autopsy—not usually from the surgery, but die from other causes—and upon autopsy, they never found the collateral vessels.”

So where did the pain relief come from? Doctors decided to do an experiment to see if the placebo effect had anything to do with it.

“They took the next series of patients that came into their hospital, who were appropriate candidates for mammary artery litigation, and they did most of the surgery as usual,” Dr. Siegel said. “But they didn’t actually touch the heart. They just sewed people back up again and told them that they had had successful mammary artery litigation. They then followed these patients and saw what happened once they healed.”

The results were stunning—the same success rate of angina pain relief from the actual surgery were reported after the sham surgery. Eighty to 90 percent of patients claimed the surgery had successfully alleviated their angina.

The new study of doctors’ attitudes towards treatment success sheds light on the placebo effect from a woefully understudied angle, but placebos are here to stay. This newly published research may even cause doctors to change their bedside manner in the future.

Dr. Ronald D. Siegel contributed to this article. Dr. Siegel is an Assistant Clinical Professor of Psychology at Harvard Medical School/Cambridge Health Alliance. He received his Doctor of Psychology degree from Rutgers University and completed his clinical internship and postdoctoral fellowship at Harvard Medical School.