Placebos have been studied more than any treatment in the history of medicine, yet they remain mysterious. I have been studying placebos for 20 years and have conducted some major studies that have advanced scientific knowledge in this area. Here are six facts about this strange effect that still fascinate me.
1. Placebos have a darker cousin: nocebos
A 29-year-old builder had to go to hospital after jumping on a 15cm nail which had become lodged in his shoe.
Moving the nail was so painful that she had to be sedated with powerful drugs (fentanyl and midazolam) to remove it. But when he took off his boot, doctors discovered that the nail had entered between his toes. The builder’s pain was caused by the mistaken belief that a nail had entered his foot.
The harmful effects of negative expectations are called the nocebo effect. For evolutionary reasons (survival depends on avoiding danger), nocebo effects are larger than placebo effects.
Unfortunately, patients are often told more about the bad things that happen than the good things that happen, which can result in a self-fulfilling prophecy. For example, learning that a medication has a potential side effect of nausea or pain may actually cause nausea or pain.
2. Placebos work even if people know they are placebo
Linda Buonanno suffered from irritable bowel syndrome so badly that she often could not leave the house for weeks. She signed up for a trial of an “honest” (open-label) placebo, which is a placebo that the patients know is a placebo.
Harvard doctors in the trial told him that the pills were “placebo pills made from an inert substance, like sugar pills, which have been shown to produce significant improvements in clinical studies.” [irritable bowel] symptoms through mind-body self-healing processes”.
The honest placebo worked so well that she was able to resume a normal life.
Honest placebos have worked in other trials to treat depression, back pain, and attention deficit hyperactivity disorder (ADHD).
Honest placebos work because of our subconscious expectations. Our past experiences with doctors and hospitals can create subconscious expectations that activate our body’s internal pharmacy, which produces morphine (endorphins) and other beneficial drugs.
3. Honest placebos are morally acceptable
Giving placebos to patients is often considered unethical by doctors because it allegedly involves lying (telling patients that the sugar pill is a powerful drug). But honest placebos don’t involve lying, so there’s no ethical hurdle.
In an ongoing trial, doctors asked patients if they would be willing to try a mixture of a real pain reliever and an honest placebo. Patients in this trial have the same level of pain relief after surgery, but they are less likely to be dependent on painkillers.
4. Placebo effects are part of most treatment effects
When a doctor prescribes ibuprofen for back pain, the effect is due to the ibuprofen and the patient’s beliefs and expectations, which may be influenced by the doctor’s communication. Doctors who convey positive messages in a warm and sympathetic manner will enhance the effectiveness of the medications.
The size and color of the pill can also affect effectiveness. A larger, orange pill may reduce pain more than a smaller, red pill.
In contrast, blue pills generally have a sedative effect – except for Italian men, for whom blue pills have a stimulating effect), perhaps because their respected football team wears the color blue.
Doctors’ ethical duty to benefit patients states that they have an ethical duty to maximize the placebo effect of all treatments they provide.
5. You don’t need a placebo to have a placebo effect
In one trial, patients were given morphine through an intravenous line after surgery. However, only half the patients were told they were receiving morphine. Patients who were told received 50 percent more pain relief than those who were not told they were being given morphine. This is an example of a placebo effect without a placebo.
6. You can induce placebo (and nocebo) effects in yourself
All communications can have beneficial or harmful effects. One study found that teaching families communication skills reduced anxiety and depression. On the other hand, couples who focused on problems and negative aspects of their relationships had weaker immune systems in one study.
Acts of altruism, focusing on a brighter future or gratitude are proven ways to reduce the impact of negative communication. An easy way to generate a positive placebo effect for yourself is to perform a random act of kindness, like offering a coworker tea, or simply smiling and saying hello.
You can learn more about the amazing effects of placebos and nocebos in my latest book, The Power of Placebos: How the Science of Placebos and Nocebos Can Improve Health Care.