Tech UPTechnology“It works for me”: placebo effect in action

“It works for me”: placebo effect in action

Pseudotherapies such as homeopathy , Bach flowers, acupuncture or reiki have never been proven effective by quality clinical trials. In fact, in some cases it has been possible to prove its ineffectiveness, either experimentally, or due to physical, chemical or biological impossibility .

“It works for me”

Many people claim that one of these or other pseudo-therapies works for them. The argument “it works for me” lacks scientific validity, although many people say so – it is often said that the plural of “anecdote” is “anecdotes”, and not “scientific evidence” -. There are many ways in which a truly ineffective substance or technique can appear effective to some people.

In the first place, certain pathologies remit spontaneously; in other cases, it may be that the person, in addition to the pseudotherapy, is receiving a really effective treatment. In any case, the most common is that a false attribution of cause occurs where there is only one coincidence.

However, whether or not this false cause-effect relationship is attributed, the placebo effect plays a relevant role in the subjective perception of “it works for me”.

The placebo effect “works for me”

The placebo effect is the improvement of the symptoms of a pathology, which is not attributable to any really effective treatment, but to a series of interactions, rituals, symbols or acts that the patient subjectively perceives as positive . The administration of a substance lacking pharmacological activity or clinical relevance is very common in the placebo effect, although not always.

This paraphernalia of reinforcements and rituals generates an effect of suggestion in the patient, mediated by complex neurobiological mechanisms that involve certain neurotransmitters and the activation of specific areas of the brain and the amygdala.

As a physiological response, the patient benefits from symptom relief, which will be different depending on the person, their suggestibility, the type of symptomatology and the form and complexity of the administered placebo.

However, although scientific research has revealed that there are specific and objective neurobiological pathways and a correlation between these and the relief effect, scientific evidence shows that the therapeutic benefits associated with the placebo effect do not go so far as to alter the pathophysiology of the diseases.

The placebo effect, in short, is the observed result in the form of symptom relief produced by products or actions that, in reality, lack real clinical efficacy.

Distinguish what “works for me” from what is really effective

Given that the placebo effect exists, when a new drug is developed and its efficacy is tested, it is necessary to “clean” the results of any interference that may generate said placebo effect.

The clinical tests are organized around two groups of people, one that receives the new drug, is the experimental group , and another that does not receive it, is the control group . If the new drug seeks to treat a pathology for which there is already proven treatment, that treatment is applied to the control group; but, if it is a new treatment , the control group receives a product identical to that of the experimental group —in size, shape, administration or even taste— but that lacks the active ingredient and, therefore, is ineffective in solving the problem. This substance, with its associated paraphernalia, is what is called a placebo .

As part of the protocol, neither the patient nor the person who administers the treatment must know who receives the placebo or the experimental treatment, since knowing this information, especially by the administrator, can cause personal behavior that is different from each other and alter the results. This protocol is called double-blind – the patient is blind, and the investigator is blind.

In this way, all patients are susceptible to the placebo effect, and only when significant improvements are observed in the experimental group with respect to the control group, it can be confirmed with sufficient reliability that the treatment is effective and its effectiveness can be quantified.

“It works for my baby and my pet”

Even when working with babies or animals , it is important to take the placebo effect into account. In babies it is very clear: the classic “healthy, healthy” that the mother says to her son who has just fallen while she runs her hand over his knee and the crying stops, is nothing more than a placebo ritual.

In animals it is not so easy to observe, but it also happens. Rats, pigeons, crows, horses or dogs are extraordinarily perceptive, capable of creating their own rituals and associating those rituals with intentions.

If a group of rats are given a foreign substance of a specific taste or injected intravenously, they perceive that they are receiving a particular treatment, different from the usual one, a ritual that has changed, and develop a placebo response. . This response, the studies indicate, responds to Pavlovian conditioning, so that any animal susceptible to suffering this type of conditioning could, in principle, respond with a placebo effect.

Some defenders of pseudotherapies assure their efficacy in the treatment of plants , organisms without a nervous system, which cannot have any placebo effect. Indeed, it may happen that the plants improve, what they do not take into account is the suggestive effect on the person who cares for them. By knowing which plant receives the experimental treatment and which does not, the caretaker may unconsciously treat each plant differently. And a better cared for plant is usually more likely to overcome a pathology.

For this reason, any trial, even with plants or cell cultures, must always be carried out with a control group and following the double-blind protocol so that the placebo effect does not cloud the results of the research.


Herrnstein, R. J. 1962. Placebo Effect in the Rat. Science, 138(3541), 677-678. DOI: 10.1126/science.138.3541.677

Kaptchuk, T. J. et al. 2015. Placebo Effects in Medicine. New England Journal of Medicine, 373(1), 8-9. DOI: 10.1056/NEJMp1504023

Meissner, K. et al. 2018. Are Blue Pills Better Than Green? How Treatment Features Modulate Placebo Effects. En International Review of Neurobiology (Vol. 139, pp. 357-378). Elsevier. DOI: 10.1016/bs.irn.2018.07.014

Shang, A. et al. 2005. Are the clinical effects of homoeopathy placebo effects? Comparative study of placebo-controlled trials of homoeopathy and allopathy. The Lancet, 366(9487), 726-732. DOI:

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