Placebos are inactive treatments that shouldn’t, in some sense, have a real effect. And yet they often do. But the chemical basis of the placebo effect, despite its enormous importance, is still largely a mystery. A study published this week in Nature Medicine shows that cannabinoid receptors are involved in the placebo response to pain, which hasn’t been demonstrated before. The finding implies that the brain’s own endocannabinoids can fight pain, and actually do it via the same pathway as several compounds in the cannabis plant.
You’ve heard of the placebo effect—the tendency for patients who receive a phony treatment like a sugar pill to feel better just because they think the treatment will help them. That standard definition relies on deception. Surely the placebo effect doesn’t work if you tell the patients they’re taking placebos, right?
Not necessarily, a new study finds. And, as DISCOVER blogger Ed Yong notes, this brings up an interesting ethical question:
Can doctors justifiably prescribe placebos to their patients? The standard answer is no. Doing so patronises the patient, undermines their trust, and violates the principles of informed consent. It compromises the relationship between doctor and patient. At worst, it could do harm.
But many of these arguments are based on the idea that placebo effects depend on belief; people must expect that treatments will work in order to experience any benefits. For a doctor to prescribe a placebo, they’d need to deceive. But according to Ted Kaptchuk from Harvard Medical School, deception may not be necessary. In a clinical trial, he found that patients with irritable bowel syndrome (IBS) felt that their symptoms improved when they took placebo pills, even if they were told that the pills were inactive.
For plenty more about this, check out the rest of Ed’s post at Not Exactly Rocket Science.
Not Exactly Rocket Science: The Placebo Effect Affects Pain Signaling in the Spine
Not Exactly Rocket Science: A Biological Basis for Acupuncture, or More Evidence for a Placebo Effect?
80beats: 50% of U.S. Doctors Secretly Dose Their Patients—With the Placebo Effect
DISCOVER: Is the Placebo Effect a Myth?
Image: flickr/Fillmore Photography
About half of surveyed U.S. doctors say they regularly prescribe placebos without their patients knowledge, and most admit to no qualms about handing out vitamins, aspirin, and other benign pills that have little relevance to the symptoms their patients complain of, according to a new study. Several medical ethicists say they’re troubled by the results, including study coauthor Franklin Miller: “This is the doctor-patient relationship, and our expectations about being truthful about what’s going on and about getting informed consent should give us pause about deception” [The New York Times].
Study coauthor John Tilburt says these findings are a reflection of the modern mentality that for every symptom you may experience, there’s a pill to make it all better…. “Doctors feel pressured to prescribe something in order to show the patient that they are taking their symptoms seriously and trying to do something about it, so they try to find creative ways to make patients feel better, and will use any tool available, including psychological benefits” [ABC News].