You’ve heard of the placebo effect, but what is the nocebo effect? Is pain only in the mind?

When Dr. Henry Beecher ran out of morphine to offer wounded soldiers during World War II, he began administering normal saline to give soldiers at least the impression they were getting pain relief.

After the soldiers reported reduced pain, this was the beginning of Beecher’s research into what he later called the placebo effect: a beneficial effect caused by a patient’s positive views about a treatment. But what happens in the opposite scenario?

When a patient has negative expectations that a treatment will cause harm, and this belief leads to negative outcomes, this is known as the ‘nocebo’ effect. A study published Monday in the journal Communications Psychology found that a nocebo effect can spread. There is evidence that individuals’ experience of pain is enhanced by witnessing others’ responses to the same treatment.

Dr. Kirsten Barnes, the study’s lead author from the University of New South Wales’ School of Psychology, said while less is known about the negative counterpart of placebo, the topic is gaining interest.

Can a nocebo effect be transmitted?

In Barnes’ survey among 101 participants, people were paired up and each person in the pair was given the role of ‘protester’ or ‘observer’. The protester was equipped with a small pulsating heating plate that was thought to emit an electrical current that would worsen the pain.

They were told to learn from each other when the treatment was turned on or off, based on the presence of a green or blue square on a computer screen in front of them.

In the first demonstration, the heat intensity was increased when the blue square was presented, but the same heat intensity was applied to all other demonstrators regardless of whether they saw the green or blue square.

“We found that when observers moved to the protester’s position, they reported more pain to the blue square, even though there was no difference in the intensity of the heat,” Barnes said.

The results showed that “they learned about the negative effects of the treatment by looking at another person and then passed on their own nocebo effect to the next person who looked at them. This change in pain was present in their pain ratings, but also in their facial expressions and their physiological response,” she said.

Where have we seen other examples?

Historical examples have shown that watching other people experience symptoms such as pain can worsen those same symptoms in the observer, causing mass psychogenic illnesses – where fear causes physical symptoms – first described more than 600 years ago.

In November 1998, when a teacher at a Tennessee school smelled gasoline in her classroom and experienced headaches, nausea, shortness of breath and dizziness, 100 teachers and students also ended up in the emergency department due to the allegedly toxic exposure. no medical or environmental explanations for the reported diseases have ever been found.

A similar mass psychogenic illness occurred at a school in Ripon in Britain. More recently, Tourette-like symptoms have been observed in young people in Germany after watching videos of similar behavior on social media.

Dr. Amelia Scott, clinical psychologist and research fellow at Macquarie University, said: “It is highly likely that nocebo effects are partly responsible for many public health fears, which can sometimes be amplified by alarming media reports or social media posts. For example, there are indications that there are large peaks in the number of people reporting side effects of medications after media reports raised the alarm.”

So is pain all in the mind?

Prof. James McAuley, director of Neuroscience Research Australia’s Center for Pain Impact, is a back pain researcher and says he has seen evidence of both placebo and nocebo effects.

“This research is so important because it shows that the pain someone experiences is not always just due to what is happening in their body,” he said.

“It does not always depend on how much damage there may be where they can feel the pain. Your brain, and the processing that takes place in your brain, play a crucial role in whether or not you experience pain, but also in the intensity of that experience.”

McAuley said the study clearly showed that pain can be learned from other people, especially from other people you are close to, with a “social contagion of nocebo and possibly also of placebo.”

So what should we take away?

Scott said the social transmission of nocebo effects makes sense from an evolutionary point of view. “It is a highly adaptive trait that promotes our survival if we can be attuned to each other’s experience of unpleasant symptoms, especially pain,” he said.

However, it can have negative consequences for contemporary healthcare. Barnes said there are many places where we can see other people having negative experiences with treatment – ​​such as in shared hospital wards, emergency departments or when donating blood.

McAuley said the research also had implications for group therapies. For example, exercises for back pain are often performed in groups.