Placebo Effect In Animals: What It Is And Why It Appears
The placebo effect is a phenomenon that we generally tend to relate to human beings, since in order for it to be possible, the existence of certain cognitive abilities that we generally assume do not exist in other beings is necessary. And for this effect to occur, it is essential that there be the perception or idea that a specific stimulation is going to generate a specific effect on a specific problem, something that requires complex processing of both internal and external information.
However, the truth is that we are not the only beings who have reported benefiting from this effect. This is, There is a placebo effect in animals a topic we are going to talk about throughout this article.
Before delving into the possibility of finding the placebo effect in non-human animals, it is necessary to briefly clarify what we call the placebo effect.
The placebo effect is understood to be that situation in which an individual with a specific problem presents an improvement in symptoms that is attributed to the effects of a supposed medication or treatment that is considered to produce said improvement, despite the fact that in reality the treatment itself has no therapeutic effect on the problem.
We would therefore be faced with an improvement generated by autosuggestion, with the belief that following the treatment has to or will produce specific effects on our health. This is not an illusion or a false perception but the improvement is generally real and palpable for the patient, but it is the product of the action of the mind on the body and not the effects of a specific drug or intervention.
Why is it considered typical of human beings?
Based on the previous definition, we can understand why at a popular level we tend to think of the placebo effect as something specific and unique to human beings: being able to imagine that a specific substance or intervention is going to improve us from an ailment implies identify both the ailment and the substance/intervention and generate the belief and expectation that taking the substance will eliminate or reduce the ailment we suffer from.
That is, it requires a certain capacity for imagination, planning and abstraction when projecting positive properties to the substance itself for the specific situation in which we are. It also requires the ability to make expectations about the possibility of recovery.
The placebo effect in animals
The large number of cognitive abilities that are assumed to be necessary and essential for the placebo effect to arise collides head-on with the traditional perspective that sees the rest of animals as beings with lower cognitive abilities, this being the reason why it is not generally considered that it can occur in animals. But the truth is that it does.
It has been experimentally demonstrated with different animals, including dogs, that the provision of certain care and completely harmless substances can generate a positive effect on the immune system, through case-control studies.
In situations in which a group of animals was treated for a specific disease with a drug and others with a placebo, improvements were observed in both groups (obviously greater in the group treated with the real drug). This improvement was observed with different measures, independent of the subjective assessment of owners or veterinarians. There are multiple disorders in which this effect can be observed, and it can even cause slowing down of tumor growth.
There are multiple possible explanations for this fact, with different authors having developed various theories and models in this regard. The following are some of them, especially in the first two cases being some of the most accepted.
The theory of classical conditioning
The causes of the placebo effect in animals, and in fact also in humans, may actually be based on conditioning acquired from previous experiences: If an animal (or person) associates that taking a substance with certain characteristics has generated a specific effect on its body (for example, feeling calmer after drinking a liquid of a certain color or taking something similar to a pill), the subject The person in question will come to assimilate the improvement with the stimulation in such a way that he will tend to believe that he will improve on future occasions.
This is something that happens in humans when we take a pill that they give us in a state of pain: in a short time the pain is reduced because we have assimilated that said pill will do like drugs that we have previously taken (for example the typical Gelocatil).
The same goes for animals: yes swallowing a pill is repeatedly associated with feeling better, in another situation in which the animal is unwell, it can expect this effect from a pill. This does not mean that they are going to swallow it (variables would come into play here, such as whether they dislike the bad taste or texture, or they relate the pill to its owner forcing it on them).
Cognitive model: expectations
Probably the model that has had the most difficulty in applying with non-human animals is the one that refers to expectations, these being something linked to a symbolic capacity that animals are considered not to possess. However, although the cognitive capacity of each species is different, it has been observed in different beings that it is possible create expectations and feelings of ability to control or lack control over situations as well as the existence of learning in the face of stimulation.
The most obvious example (although it would be rather the opposite of the placebo effect, the implications are the same) is that of learned helplessness: doing nothing to avoid something because it is expected that one’s own behavior will have no effects. This is typical in depressed subjects (both humans and animals), something that in turn generates a decrease in the body’s defenses. The opposite situation would generate, on the contrary, an increase in the tone of the immune system and a greater capacity to recover from illness.
The effect of stress
Another possible reason why the placebo effect may appear is due to the reduction of stress in the face of the disease. The fact of taking a drug or the activities or treatments that are carried out throughout a treatment (including trying to pet them, calm them, etc.) can reduce the stress level of the animals that follow them. Given that stress has emerged as an important risk factor and worsens the condition of sick subjects, treatment could provide relief from this stress which in turn generated symptomatic improvement.
This effect would also be linked to an effect that has also been observed: positive physical contact with an animal makes its state of health more resistant and improves the immune system, in the same way that contact with animals is usually a positive factor in the improvement of different physical and mental diseases and disorders in humans.
A theory that cannot yet be extrapolated to animals: the role of endogenous opioids
In humans, it has been observed that the perception of different degrees of discomfort, pain and physical discomfort can be greatly reduced thanks to the action of endorphins or endogenous opioids.
However, and although many animals also have this type of substances in their nervous systems, few tests have been carried out in this regard, so it is something theoretical.
The placebo by proxy
The placebo effect in animals exists and it is something that has been proven, but the truth is that it has also been observed that in some cases, as we have hinted previously, a situation can occur in which something that is interpreted as a placebo effect is not, what would be known as a placebo by proxy: the animal in question does not present a variation in its symptoms, but The people who observe it do believe that this has occurred after having been given a specific treatment.
This type of placebo occurs especially in pet owners, who are reassured by having provided some type of treatment to their animal companion and perceive it as better than before even though there may not have been an improvement in its condition.
Another situation could occur the other way around: a sick pet, upon perceiving that its human companion is nervous or upset about its condition, could become uneasy and upset to a greater extent than its problem would generate. When receiving treatment and calming down, the human being in charge, such tranquilization could relax the animal’s altered state and also produce improvement. We would be facing a somewhat different type of placebo.
