What You Need to Know About the Placebo Effect: Why It Works

PLACEBO IS HUNDREDS OF YEARS and is one of the most well-studied methods in the history of medicine. How did it happen? Perhaps because even Plato suggested treating headaches with some kind of “medicine” (nothing to do with modern drugs, of course), complete with a “spell”, without which it would not work. So today, every time we take a pill with proven effectiveness, we understand that in clinical trials it has performed better than a placebo.

“Sing a placebo”

Although today the word “placebo” is associated with us mainly with medical histories, initially it was understood a little differently. When the Roman Catholic Church created a set of rules for funeral rituals, it required singing at the funeral. In the text of the psalms, the line “Placebo Domino in regione vivorum” (“I will be well pleased with the Lord in the land of the living”) was repeated many times . Often, seeing the funeral procession, the poor and simply wanting to eat at someone else’s expense, people joined in the singing, posing as friends and relatives of the deceased. This is how the expression “singing a placebo” appeared in the sense of “doing something artificial and fake.”

Strength versus weakness

By the middle of the twentieth century, placebo-controlled trials had become widespread enough for the American anesthesiologist Henry Knowles Beecher to release his high-profile study, The Powerful Placebo. The reason for the work was what he saw while serving in the US Army during World War II. When the supply of morphine ran out, the nurses injected the wounded soldiers with salt water before the operation – but the pain relief effect still came. After the war, Beecher evaluated 15 placebo-controlled studies that combined more than 1000 people. So it turned out that the placebo was able to stop symptoms in 35% of patients.

Already in the 90s, the conclusions of the anesthesiologist were questioned . The scientific community has relied on the fact that people who felt better after receiving a placebo could be feel better, and in the event that would do nothing to take.

Armed with this thought, Danish doctors conducted a study that used active treatment, placebo treatment, or no treatment at all. In the end, they found a small placebo effect, which they did not consider statistically significant. And then they published the article “ Is the Placebo Powerless? ” (” Still , the placebo is powerless? “), The name of which directly refers to the work of Beecher. The only problem was that the methodology of this study also left much to be desired.

Placebo Surgery

While we often think of placebos as vitamins that are used in trials of a new drug to test its effect, the list of options is not limited. In fact, placebo surgery gives the best results – when the patient is told that they had an operation, but nothing is actually done. And an improvement in the condition still occurs (moreover, in 75% of cases ).

One of the most famous such experiments was carried out by the American surgeon Bruce Moseley on 180 patients with severe knee pain . Half of them he underwent real arthroscopy, and the other half underwent placebo arthroscopy. To make everything as close as possible to the truth, the patients in the placebo arthroscopy group also received an anesthetic injection and a small incision in the knee, but did not repair the damaged cartilage. Also, doctors and nurses agreed, even during a “fake” operation, to speak and behave as it would be during a real operation. In the end, the placebo arthroscopy worked as well as the real one.

Red or blue

Interestingly, placebo drugs don’t work the same way. It is known, for example, pink tablets, in contrast to blue , enhance the adrenaline level, thereby exerting on the body a greater stimulatory effect (but it does not apply to the Italian men). Colored pills, by the way, and in general, more effective than white. Branded and expensive pills tend to be more pain-relieving than cheap generics. And exactly the same two placebos are usually better than one .

Some evidence also suggests that placebo injections may be more effective than pills. And there is also a suspicion that the placebo offered at the hospital will work faster and better than what is suggested to be taken at home.

Open placebo

Incredible, but true: even if patients are told that they will not be given the real medicine now, but a placebo, the treatment can be beneficial. This approach is called an open placebo. Back in 1965 , two American doctors gave an open placebo to their neurotic patients, warning that they were sugar pills, which, however, often help people with this condition. As a result, many of the patients (although is this true for “many” if the group consisted of only 15 people?) Became better, despite the fact that they knew that of the active substances in the “medicine” only sugar.

Evidence from new studies also shows that the use of an open placebo may be beneficial. In particular – in patients with pain in the back, depression, allergic rhinitis, irritable bowel syndrome (IBS), and attention deficit and hyperactivity disorder (ADHD). Scientists think this has something to do with why the placebo effect works on humans at all .

Why Placebos Work

One would assume that the method would be effective only for gullible or easily suggestible people. But numerous experiments in the history of science have shown that this is not the case. In science the placebo effect are many explanations, but these are the most popular of them are:

Hawthorne effect

If there is a problem with human health and he asked for help, it is likely that he , along with this begin to take other decisions aimed at symptom elimination. For example, a patient with a sore knee will almost certainly begin to move the knee less and move more carefully. And a person with a sore throat, even if he is an experienced smoker , is likely to reduce the number of cigarettes smoked per day so as not to provoke irritation of the mucous membranes. Together with the novelty effect, this will help improve symptoms no matter how good the treatment was.

Regression to mean

When a person visits a doctor, their symptoms can be particularly severe. But in the natural course of the disease, every patient has days when he gets a little better or a little worse. If the drug or placebo drug is taken on the same day as the symptoms have improved, the brain is bound to link the two things together.


In the same way that Pavlov’s dogs learned to associate the sound of a bell with food, our body can learn to respond in a certain way to taking medication. For example, if a patient is given a pain pill for five days, the brain associates it with symptom relief. And when, on the sixth day, the pill is replaced with exactly the same- looking sugar placebo, he will not suspect anything – and the pain will recede. In a 2012 study , this is exactly what happened: when participants were replaced by a suppressor drug for a placebo without warning, their bodies continued to have a reduced immune response.


Finally, being a social being, a person cannot but interact with people around him. Thus, when participants in experiments see that other patients are helped by treatment , the likelihood that it will help them, too, increases. Similarly, as in the improvement of health can affect empathic and attentive doctor: in a Harvard experiment , it was found that the group of patients with irritable bowel syndrome, the placebo-treated by a doctor who was interested in their lives and empathized with him, through what they had to go faster felt better.

Interestingly, by the way, that the placebo has no effect at all. It has been proven that the analgesic effect is markedly reduced in people with damage to the frontal lobes: those who have suffered a stroke, suffered from craniocerebral trauma or suffer from dementia. But the placebo effect is undoubtedly real and very interesting, so in the future science will have a lot to learn about it.

local_offerevent_note March 10, 2021

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