Can Animals Have Mental Illness?

The health of the mind has traditionally been understood as an anthropocentric reality, exclusive heritage of our species. Animals, despite their quality as living beings, would thus be deprived of the intellect and sensitivity necessary to suffer emotionally.

The truth, however, is that all emotion that we may experience comes from very old phylogenetically brain areas, shared with countless other organisms that populate this planet. Therefore, it should not be strange that we also have some affective experience in common, and perhaps even some problem in this area.

To dispossess the rest of the animals of everything that could bring them closer to our reality would position them on a stage ideal to be used as a fungible resource, in all areas in which they are susceptible to it (livestock, industry, etc.).

In this article we will abound in the empirical evidence that allows us to answer the simple question of: Can animals have mental illness? The purpose of the text is to better understand the way in which they suffer emotional distress and what situations precipitate it.

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Can Animals Have Mental Illness?

In recent years, society has refined its sensitivity to the subjective experience of animals, so that there is even a scientific specialty (Animal Psychopathology) directed to the study of this phenomenon. In this text eight of the most common emotional problems that can present will be cited.

1. Depression

Depression is described as a state of sadness and decreased ability to feel pleasure (anhedonia), resulting from a loss perceived as significant. It is one of the great disorders of our time, and there are signs that animals can also suffer it when exposed to specific situations; such as a loss of control over the environment, a reduction of incentives and even the death of a member of their group.

The first scientific descriptions of animal depression come from works on defenselessness learned, at a time in history in which the ethical guarantees of laboratories were more lax than the current. These investigations tried to explore the negative affective reactions of a living being when experiencing adverse circumstances over which he lacked control.

Models were sought that would allow any finding to be generalized to man, with the aim of extracting environmental risk factors that could predict the decline in his mood. In these studies, a dog was usually introduced into a special cage, at the base of which were located two separate metal surfaces, which covered its entire extension longitudinally.

The experimenter proceeded to electrify one of them, to which the animal responded by changing its location and locating itself where the stimulus was not present (in the sheet without electricity). The dog repeated it without problems on all occasions when the experimental condition was administered, thus he could take effective control over his own environment (living a malaise that did not extend beyond a brief moment).

After several trials, the researcher would apply the electric current to the two surfaces simultaneously, so that the dog would not find shelter on either side of the cage. In this case, he would first try to find a place where his discomfort would end, but when corroborating the absence of viable options he would adopt a dejected attitude. Thus, he would lie down to endure all the shocks with a very deep apathy, developing a progressive abandonment of his most basic needs.

With studies like this, not only was evidence obtained on how depression is triggered in humans, but it was also possible to infer similar emotional states in other animals.

2. Duel

Some mammals (such as elephants or chimpanzees) seem to have a precise idea about what death is, and even develop farewell "rituals" when a member of their pack dies. In fact, there is evidence that they are not only aware of the finiteness of their organism, but that they also have rules regarding what that is considered "good" or "bad", adapting these notions to the realm of life and death (looking for the first and fearing the second).

These animals go through a process of mourning before the loss of a loved one, in a very similar way to that which has been described in the classical models for the human being. They can resort to physical spaces in which to watch over the remains of those who preceded them ("cemeteries" next to rivers in which the corpses of dying elephants accumulate that tried to drink at their last gasp), and even show behaviors suggestive of dealing affectively with the absence (such as reduced food intake, sleep disturbance, etc.).

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3. Suicide

There is evidence of marine mammals (such as dolphins) that may make the decision to kill themselves in certain circumstances, both in freedom and in captivity.

The mechanism they usually use consists of stranding their body on the coasts or on the shores, on a land surface on which their tissues suffer to death. There have been many causes that have been postulated for this tragic phenomenon, until recently restricted to the human sphere.

The investigations carried out in this regard yield two different conclusions: that the dolphin's autolytic behavior is due to disorientation space resulting from the use of sonars and other human technologies, or that may be the consequence of unbearable suffering derived from a pathology physical. In the latter case it would be a behavior analogous to that which can be observed in humans, when suicide is motivated by a state of very intense organic or emotional pain.

4. Addictions

Addictions in animals are very rarely observed when living in the wild, so the evidence on these comes from laboratory studies. Thus, it has been observed that rats and mice show a preference for water mixed with substances such as cocaine, or simply with sugar (which is a natural reinforcer), and the existence of the fundamental symptoms of any addiction has been demonstrated: tolerance (need to consume a greater amount of drug to achieve the same effect) and withdrawal syndrome (discomfort in the absence of substance).

And it is that the brain structures involved in addiction, the nucleus accumbens and the ventral tegmental area, are common to a wide variety of animals. Dopamine would be the neurotransmitter that would orchestrate the neural network; activating before the stimuli that facilitate survival (sex, food, etc.), generating pleasure (high hedonic tone) and increasing motivation for them. The effect of the drug would alter its allostasis and reduce the pursuit of what was once gratifying, thereby completely dominating the animal's behavior.

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5. Activity anorexia

Activity anorexia is an eating disorder that has been observed in rats under laboratory conditions, when their access to food is restricted and indiscriminate use of a wheel is allowed to exercise on. In conditions in which both elements are present, the animal learns to make proper use of them, but in the new situation he resorts to physical exercise until exhaustion or even death.

When the problem is consolidated, the animal persists in this pattern (poor diet and intense physical exercise), even after restoring normal access to food. Theories suggest that it is a behavior aimed at promoting the search for a new environment when the former has ceased to provide the material support necessary to ensure the maintenance of the lifetime.

6. Pica

Pica is an eating disorder in which the subject ingests non-nutritive elements, such as sand or clay, and may suffer from parasitic infections or damage to the digestive system. This behavior has been observed in farm animals subjected to basic nutrient restriction, such as feed or grain, that develop the habit of eating inorganic elements (wood, plastics, etc.) whose digestion may be impossible. These animals include roosters, chickens, and other poultry.

On other occasions, the deficiency situation (in phosphorus) would make it easier for herbivorous animals to nibble on bones in order to compensate for their deficit (osteophagy). Although it is a behavior with an adaptive purpose, it can persist despite reestablishing appropriate diets, thereby diluting its usefulness for survival itself. Finally, the problem has also been evidenced in cats, in which the ingestion of threads or fabrics can be seen that can cause very serious problems in the intestines.

7. Ritualized behaviors

Ritualized behaviors occur frequently in wild animals that are subjected to states of captivity, in which they have a physical space very different from the one they could enjoy in a Liberty. These are repetitive behaviors that lack a clear purpose, and that they do not contribute to the satisfaction of the essential needs for their survival. They have been described in a great variety of animals, and they suppose an aberration of the habits that incapacitates them to reintegrate in the nature.

In birds, alterations in song and pecking have been observed, which erode the ability to communication with other individuals and damage the structure of the organs necessary for food and the toilet. It is also common in animals used for show or exhibition, such as rhinos and felines, that when living in confined spaces for a long time time they see their motor skills altered (limiting themselves to circling in small diameter circles even when they are released to their environment of origin).

8. Stress

Stress is a physiological response common to many species, and by no means unique to humans. There are many situations that can cause stress to an animal: from confinement to confined spaces excessive manipulation (by people) or isolation from other members of their species. This last factor is key in certain varieties of primate, that live inserted in hierarchical communities and that can have different levels of stress depending on the place they occupy in them (higher among non-dominant males of intermediate degree).

It has also been observed that social and environmental isolation can lead to self-injurious actions in many species of animals, especially all primates and birds, which can harm themselves when caged or isolated from the environment (in socially poor spaces). Common self-drive actions involve scratching and biting on various parts of the body, as well as plumage plumage in birds.

Conclusions

Animals are susceptible to emotional problems, especially when they are extracted from their natural environment (in zoos, circuses, etc.). Research on this question is currently increasing, and it is expected that in the future it will become an area of ​​deep scientific interest.

Bibliographic references:

• Bielecka, K and Marcinów, M. (2017). Mental Misrepresentation in Non-human Psychopathology. Biosemiotics, 10, 195-210.
• Laborda, M., Míguez, G., Polack, C.W. and Miller, R.R. (2012). Animal models of psychopathology: Historical models and the Pavlovian contribution. Psychological Therapy, 30 (1), 45-49.