The placebo effect, an improvement in health that occurs when a clinical trial patient is given a dummy pill, works even when the patient knows the medicine is fake, according to a Harvard study.
Fifty-nine percent of patients with irritable bowel syndrome who were given placebos described to them as “like sugar pills,” reported relief of their symptoms, compared with 35 percent of those who got no treatment at all, according to a published in the journal PLoS One. Placebos are mostly used in trials as comparisons to drugs being studied.
Doctors often think the placebo effect exists because patients believe they are getting a real medicine, and their expectations that they might benefit helped improve their symptoms, said Ted Kaptchuk, an associate professor of medicine at Harvard Medical School in Boston. It was conventional wisdom, and, until now, no one had tested it in a clinical trial to see if it was true.
“People just assumed it was that belief was important, and that was never tested, and I don’t know why,” said Kaptchuk, the lead author, in a telephone interview. “A lot of what we think we know about placebo was conjecture that got firmed up as truth.”
Being able to tell patients they are on a placebo is important ethically, said Kaptchuk.
Doctors already prescribe placebos outside of clinical trials without telling patients they are receiving dummy pills, according to a study in the Journal of Internal Medicine. The research found that about 45 percent of doctors at Chicago medical schools said they had prescribed placebos in regular clinical practice, not as part of a study.
If placebos require the patient to believe that they are getting a real treatment, the doctor must lie to a patient to prescribe one, violating the ethical mandate that a patient must give informed consent to treatment, Kaptchuk said. The new research, if confirmed, may show lying to a patient to reap a placebo’s benefits may not be necessary, he said.
In the study released today, 80 patients with irritable bowel syndrome were either given an inactive pill or no treatment. After 21 days, 59 percent of those who took the dummy pills reported adequate symptom relief, compared with 35 percent who said they felt better after no treatment.
IBS, a chronic disorder characterized by abdominal pain, is an ideal candidate for a disease to examine the placebo effect, said Harvard Medical School associate professor of medicine Anthony Lembo, the senior author on the paper. That’s because there tends to be a high placebo response rate in clinical trials of drugs for the disease.
Doctors in the study explained to the patients that placebos have been shown in many clinical studies to benefit patients, even though they have no active ingredients. That may have set up the patients’ expectation that a placebo would work, said Lembo. Patients may have believed they were receiving an active treatment, although not a drug therapy.
Both groups of patients received medical attention from doctors, which may have also allowed for patients to improve.
Other illnesses that may respond well to placebo include depression, chronic pains such as lower back pain, arthritis and headaches, and fibromyalgia, a chronic pain illness affecting muscles, said Kaptchuk. The researchers hope to do a larger trial in IBS to confirm their early findings.
The study was funded by the National Center for Complementary and Alternative Medicine, part of the U.S. National Institutes of Health.