Placebo: what it is and how it even affects babies and animals – 09/22/2023 – Balance

During her doctorate, dental surgeon Laís Valencise Magri decided to test a laser-based therapy for the treatment of pain affecting the face.

To do this, she selected some women who had the problem and divided them into two groups: the first received the “real” treatment, with a laser, while the second even had contact with the light-emitting device, but without any therapeutic action.

Important detail: neither volunteers nor researchers knew who was part of each group.

At the end of the experiment, the mystery was solved and everyone involved knew who actually received the laser or a light without therapeutic action.

But the dentist decided to do a new test at the time of the reveal. For half of the group, Magri first asked how the pain in the face was — and only then revealed whether the person had had laser treatment or not.

For the other group of participants, the strategy was the opposite: they would immediately say the type of treatment performed (laser therapy or light), and then ask whether the discomfort on their face had improved.

“We wanted to see if knowledge about the modality received influenced the immediate perception of pain”, points out the dentist, who works at the Faculty of Dentistry of Ribeirão Preto at the University of São Paulo (Forp-USP).

“And we saw that yes: when the patient knew beforehand that she had not undergone the laser, she said she was in more pain compared to situations in which this information was only given later”, she summarizes.

“The same happened in the active treatment group: if the volunteer knew beforehand that she received the laser, she tended to report less pain.”

Magri’s work is a classic example of a phenomenon that still intrigues Science and Medicine today: the placebo effect.

The concept, which has a series of definitions and has been involved in several controversies, helps to describe how substances or interventions that do not have a known therapeutic action can work in practice and generate an improvement in symptoms that afflict the body and mind — even in babies and pets.

It shouldn’t work – but it does…

Placebo has a series of definitions depending on the context in which it appears.

In the health area, the phenomenon can serve as a comparison measure for studies that evaluate new treatments.

“The idea here is to create a situation in which I will test the effect of an intervention, such as a new medicine. Then, for one group, I actually give the medication and, for another, I offer the so-called flour pills”, explains the psychologist Edna Kahhale, professor at the Pontifical Catholic University of São Paulo (PUC-SP).

In this context of clinical trials, the expectation is that the new pharmaceutical product will have a greater effect than the placebo — if the result is the same or lower, this means that the medicine does not work as expected.

Ideally, this division of volunteers between groups should be random (or randomized), and none of the parties involved with this clinical trial — scientists or volunteers — should know who received treatment or placebo (what is called in scientific jargon “double blind.” “).

There is a consensus in the area that the simple fact of knowing who is part of which group can influence and bias the results obtained at the end of the experiment. Both researchers and participants can underestimate or overestimate the effects, especially when the parameters evaluated are subjective, such as pain perception.

Concrete changes

Researchers highlighted another frequent confusion involving placebo: many people believe that this effect is false and does not change a person’s body in any way.

But not quite. “MRI studies [um tipo de exame de imagem] show that placebo can activate areas of the brain in a very similar way to what happens when a conventional pharmacological treatment is used”, highlights Magri.

In other words: to a certain extent, the placebo effect is concrete and can produce some observable changes in the body, even if limited.

The same goes for its “cousin brother”: the nocebo effect, which happens when an individual develops symptoms and side effects because they are aware that this can occur in the face of a certain treatment or illness.

“In research involving cancer chemotherapy, for example, some volunteers experience nausea and nausea because they already know in advance about the possible side effects of this type of intervention, even if they have taken a placebo substance”, says the dentist.

Another example here is so-called “white coat hypertension”, where some people experience an increase in blood pressure when they are in front of a doctor and are nervous about it.

Babies and animals

An aspect that draws attention in this debate is how the placebo effect influences babies and animals, who theoretically are not clear about the type of intervention they are receiving to treat a certain discomfort — and, therefore, would be less influenceable when evaluating possible improvements. .

But the phenomenon can also happen to them, through different paths.

Magri cites the classic research on conditioning carried out by Russian physiologist Ivan Pavlov at the beginning of the 20th century.

In short, he rang a bell every time he fed the dogs. As time went by, Pavlov realized that the simple fact of ringing the bell, even without offering a meal, made the dogs salivate.

In other words, an intervention without any direct action on the body (the sound of a bell) was capable of producing a change in the body (the production of saliva);

“Subsequently, other studies with rats, which received injections of drugs that inhibit the immune system, saw that the same effect [sobre as células de defesa] it was obtained after a while, even if they received a saline solution, without any drugs”, points out Magri.

“In the case of children, the placebo effect is also observable in practice. It is the typical case of mothers who give a kiss to their children’s wounds to make them feel better. The very expectation of an improvement can already have some results”, exemplifies the researcher.

But it is necessary to consider that the existence of the placebo effect in young children and animals is still the subject of extensive debate among experts.

Veterinarian Danny Chambers, from the Royal College of Veterinary Surgeons in the United Kingdom, cites the so-called “caregiver effect”.

“Let’s imagine the case of a dog with arthritis, which presents pain and stiffness. If you give a medicine that has been proven not to work, such as a homeopathic medicine, you may think that the animal has improved simply because you wait for an improvement to occur”, he says. he.

“We know that chronic diseases improve or worsen over days, weeks and months. The dog may feel more pain and stiffness on a cold day or after a long walk”, explains the veterinarian.

But, the next morning, when taken care of and rested for a long time, the discomfort tends to be relieved — regardless of any medicine used. However, the tendency is for the guardian to link the relief of symptoms to a pharmacological intervention, even if it has nothing to do with it.

In other words, the “caregiver effect” is more in the eyes of those observing that patient, hoping to notice any progress.

Placebo as a weapon

Anthropologist Mário Saretta Poglia, who studied the placebo effect during his doctorate at the Federal University of Rio Grande do Sul (UFRGS), believes that the phenomenon has started to be used in a problematic way and with a certain moralism in recent times.

“The use of the term ‘placebo effect’ has become a category of accusation by Western Science for ancestral and traditional practices of other peoples”, criticizes him, who is currently a professor at the State University of Paraná.

“The placebo effect has become an obligatory point of passage to understand evidence-based Medicine and the claim of Medical Sciences.”

The researcher understands the placebo as a mark of scientific rationality, but finds himself “concerned with the multiplicity and legitimacy of different therapeutic procedures”.

“And science itself and researchers cannot reach a common denominator on what the placebo effect is,” he points out.

Poglia understands that it is necessary to produce “an ethics around the placebo effect” to better understand “the connection between human beings and the environment”.

Can you take advantage?

But knowing that the placebo effect happens — and can produce tangible changes in the body — will it be possible to take advantage of it?

At first glance, it makes no sense for health professionals to deliberately prescribe “flour pills” or other proven ineffective treatments, experts point out.

“There is an ethical and legal issue here. In the office, we should only use practices that have scientific proof and are based on evidence”, points out Magri.

But this does not mean that certain aspects of the placebo effect cannot be used in practice — and some of them are already part of the daily lives of healthcare professionals (and even the pharmaceutical industry itself).

“We know that even the color of the pill can influence the result. The blue ones tend to cause a calming effect, for example. The size of the pill is another factor: the larger ones are subjectively seen as more effective. The same goes for the price: medications more expensive ones can have a greater result than cheap generics in some individuals”, says Magri.

According to the researcher, some investigations suggest that even the presence of diplomas hanging on the wall of an office ends up influencing the patient’s confidence in a given treatment.

“Even the way a diagnosis is communicated can have an impact here. The patient of a doctor who presents the facts in an optimistic way tends to feel better compared to one who receives the news in a passive or non-hopeful way”, she explains. .

In the researcher’s view, the way health professionals communicate can make all the difference — and represent a good way to take advantage of a phenomenon as common and fascinating as placebo.