The nocebo effect: what it is and how it works, interesting examples

Posted on Sep 23, 2022      16

The placebo effect. Does the word combination sound familiar? We wrote about it in the last article. Today you will learn about a lesser-known antipode of the placebo. The dark side of brain suggestibility is the nocebo effect.

Let’s tell you why nocebo makes people suffer, but first things first.

What is the nocebo effect in simple words?

The Nocebo Reaction, written by Walter Kennedy, was published in 1961. It was this doctor who first described the negative effects of placebos and called them the nocebo phenomenon.

So, what is it? A nocebo is a remedy that has no real pharmacological effect, but causes a negative reaction in the patient, ranging from dizziness and headaches to death.

For pain that disappears for no apparent reason, doctors immediately think of the placebo effect. Sometimes a person feels better simply because he sincerely believes in the treatment's efficacy. Although in reality there is no cure. Seeing this phenomenon in a scientific experiment is quite difficult.

Another thing is the inverse effect called nocebo-if a person is convinced that he should feel pain, he becomes in pain.

A simple example

Scientists conducted an experiment to see if the nocebo effect could actually cause pain. The subjects were divided into two groups and all were injected with saline (harmless to the body). The first group was told that an itch-inducing allergen was being injected, while the second group knew the truth.

Those who were told about the allergen experienced itching. This phenomenon is called the nocebo effect.

There are usually 3 qualities that cause the nocebo effect these are:

  • suggestibility;
  • anxiety;
  • Mistrustfulness.

Let’s summarize: what is the difference between the nocebo and placebo effects? Both effects are based on faith, only with placebo it is faith in the drug, that it will help, and the nocebo effect is based on faith in the disease, which should appear because of the drug.

In simple words, the placebo effect is a phenomenon in which the patient’s condition improves; with the nocebo effect, it worsens.

How the nocebo effect occurs

  1. Side effects. The instructions for each medication list the side effects. It is they that can activate the nocebo effect. Particularly suggestible and anxious people may feel worse immediately after reading the instructions. Also, some people talk about the negative impact of side effects on health after taking the medication, even if they do not manifest themselves.
  2. MEDIA. Sometimes a person doesn’t even need medication to manifest the nocebo effect. He winds himself up. For example, if a girl is afraid to get sick or infected and expects it by listening to the news, reading posts on social networks about the flu epidemic, she may actually get sick without aim reasons.
  3. Doctor’s credibility. By reporting side effects, the doctor wants to prepare the patient for negative consequences by reducing anxiety. But often it is just the opposite - thoughts breed disease.
  4. Word of mouth. A case in New Zealand in 2007 is a case in point. Eltroxin, a thyroid medication, was in the spotlight. The manufacturer only changed the color and form of the medicine slightly, and the rumor spread among the people about a conspiracy, about hiding the truth from the population. After that, doctors recorded two thousand complaints about side effects in a year and a half. Interestingly, before that, there had been almost no complaints.

Size and price also have a definite effect. A large and expensive pill activates a stronger nocebo effect than a small and cheap counterpart.

How the nocebo effect works

Nocebo can drive an impressionable person to a grave condition or even to death. African sorcerers’ curses were based precisely on this effect. Tribal members were convinced that the shaman possessed magic, and those subjected to the curse soon died.

Little has changed now, except that not all people believe in magic. A gullible and suggestible patient can die if doctors mistakenly diagnose him as deadly.

Under the nocebo effect, the nervous system signals other human systems. The hormonal system is worth highlighting: immunity weakens, production of the hormone dopamine decreases, and pain increases.

Scientific discoveries

Scientists at the University of Michigan John-Kar Zubieta, using positron emission tomography, have explained why nocebo increases pain.

Nocebo’s effect is related to a decrease in the hormone's production of dopamine, which is involved in the production of opioid peptides that have an analgesic effect.

Italian scientists led by Fabrizio Benedetti did not stand by and made their discovery.

They claim that the nocebo effect is triggered through anxiety, which is caused by the expectation of pain.

For example, if a reputable physician informs a patient about the negative effects of a drug, the person may have anxious thoughts that lead to health problems.

Pain through observation

It turns out that the nocebo effect can affect a person if they learn about other people’s negative experiences. The study was published in The Clinical Journal of Pain in September 2019.

  • In the experiment, volunteers watched a video of a woman experiencing pain during a pressure test. Volunteers were then subjected to the same test and they, too, felt pain.
  • Later, the procedures with watching the video were repeated with other subjects, only in the video the woman no longer showed signs of pain. The participants of the experiment felt no pain this time.

In the same way, people’s stories on the Internet about the negative effects of something affect a person.

Who is more affected by the nocebo effect?

To determine the groups most affected by nocebo, scientists from Switzerland conducted a meta-analysis. Publications from January 1997 to March 2018 were studied. In the end, the conclusion was quite expected.

Individuals with pessimistic attitudes and anxiety disorders were most susceptible to nocebo while an optimistic outlook enhanced the effects of placebo.

Negative expectations can weaken the effectiveness of treatment

The nocebo effect can manifest itself even with strong pain medications. Professor Luana Colloca of the University of Maryland proved this experimentally.

The protagonists of the experiment were two groups of patients who had recently undergone surgery and were taking morphine (a painkiller).

  1. One group was told that in a few days, they would stop taking the painkiller. As a result, the subjects in the first group complained of increased pain even before the morphine was discontinued.
  2. Later, the second group was deprived of pain medication without informing them about it. To the doctors’ surprise, only a few reported any changes or complained of pain.

The research team suggested that nocebo thus prepares the body for unpleasant symptoms or phenomena. The nocebo effect, like fear, can be a constant source of stress.

What other conclusion can be drawn? A person’s negative expectations can reflect badly on treatment, so doctors should pay attention not only to physical symptoms but also to patients’ preconceptions.

How to deal with the nocebo effect

This topic is not as well researched, but many experts highlight several good ways to counteract the negative effects.


Hypnosis engages areas of the brain associated with attention, emotion, and pain. Therefore, hypnosis can be used successfully to counteract the nocebo effect.

Some experts claim that hypnosis is an effective way to get rid of a negative psycho-emotional state. Hypnosis sessions affect the psyche and various biochemical processes occurring in the body.

But not everyone is affected by hypnosis in the same way, some are not amenable to it at all.

Change your life for the better

In order not to drown in negative emotions and to be healthy, it is necessary to change the worldview and the way of life. For starters, take up sports. Just exercising or jogging is enough to increase the hormones that make us happy.

  • Do something that you love to do;
  • Surround yourself with positive and interesting people;
  • Avoid news with a negative connotation if possible;
  • Concentrate only on the good, and problems will pass you by.

Have you ever noticed that people who do what they love until old age are less likely to get sick and live longer than those who are dissatisfied with their lives?

Stop getting yourself worked up

There’s no need to get yourself all worked up and expect to get sick. It’s better to distract yourself. As already written above, it can be a sporting activity, also great help hobbies and interesting work. Make it so that for negative thoughts you simply have no time left.

And also stop diagnosing yourself, especially according to the articles of various bloggers.