Can Animals Have Mental Illnesses?

Mental health has traditionally been understood as an anthropocentric reality, exclusive heritage of our species. Animals, despite their quality as living beings, would thus be devoid of the intellect and sensitivity necessary to suffer on an emotional level.

The truth, however, is that every emotion we can experience comes from very phylogenetically ancient brain areas, shared with countless other organisms that populate this planet. Therefore, it should not be strange that we also had some emotional experience in common, and perhaps even some problem in this area.

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

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

Can animals have mental illnesses?

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

1. Depression

Depression is described as a state of sadness and a 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 from it when exposed to specific situations; such as a loss of control over the environment, a reduction in incentives, and even the death of a member of their group.

The first scientific descriptions of animal depression come from work on learned helplessness, at a time in history when the ethical guarantees of laboratories were more lax than today. These investigations attempted 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 their mood. In these studies, a dog was usually placed inside a special cage, at the base of which two separate metal surfaces were located, which covered its entire length longitudinally.

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

After several trials, the researcher would apply the electric current to both surfaces simultaneously, so that the dog would not find shelter on either side of the cage. In this case, he would first try to look for a place where his discomfort would end, but upon confirming the absence of viable options he would adopt an attitude of dejection. 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, evidence was not only obtained about how depression is triggered in humans, but they were also able 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 They develop farewell “rituals” when a member of their pack dies In fact, there is evidence that they are not only aware of the finitude of their organism, but that they also have rules regarding what is considered “good” or “bad,” adapting these notions to the realm of life and society. death (seeking the first and fearing the second).

These animals go through a grieving process when faced with the loss of a loved one, in a very similar way to what has been described in classic models for humans. They may resort to physical spaces in which to look after the remains of those who preceded them (“cemeteries” near rivers in which the corpses of dying elephants that tried to water in their last death rattle accumulate), and they even show behaviors suggestive of being emotionally coping with the absence (such as reduced food intake, sleep disturbance, etc.).

3. Suicide

There is evidence of marine mammals (such as dolphins) that They can make the decision to take their own life in certain circumstances both in freedom and in captivity.

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

The research carried out in this regard shows two different conclusions: that the dolphin’s autolytic behavior is due to spatial disorientation resulting from the use of sonar and other human technologies, or that it may be the consequence of unbearable suffering derived from a physical pathology. In the last 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 they live 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 the substance).

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 orchestrates the neural network; activating in response to 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 search for what was once rewarding, so it would end up completely dominating the animal’s behavior.

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 the indiscriminate use of an exercise wheel is allowed In conditions in which both elements are present, the animal learns to make appropriate use of them, but in the new situation it resorts to physical exercise until exhaustion or even death.

When the problem consolidates, the animal persists in this pattern (little food 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 previous one has stopped providing the material support necessary to guarantee the maintenance of life.

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, which 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 chew bones in order to compensate for their deficiency (osteophagy). Although it is a behavior with an adaptive purpose, it can persist despite reestablishing appropriate diets, thus diluting its usefulness for one’s own survival. Finally, the problem has also been evident in cats, in which the ingestion of threads or fabrics can be seen, which can cause very serious problems in the intestines.

7. Ritualized behaviors

Ritualized behaviors frequently occur in wild animals that are subjected to states of captivity, in which they have a very different physical space than what they could enjoy in freedom. These are repetitive behaviors that lack a clear purpose, and that do not contribute to the satisfaction of the essential needs for their survival. They have been described in a wide variety of animals, and represent an aberration of habits that makes them unable to reintegrate into nature.

Alterations in singing and pecking have been observed in birds, which erode the ability to communicate with other individuals and damage the structure of the organs necessary for feeding and grooming. It is also common in animals used for show or exhibition, such as rhinos and felines, which by living in small spaces for a long time see their motor skills altered (they are limited to turning around in circles of small diameter 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 exclusive to humans. There are many situations that can cause stress in an animal: from confinement to small spaces to excessive manipulation (by people) or isolation from other members of its species. This last factor is key in certain varieties of primate who live inserted in hierarchical communities and can have different levels of stress depending on the place they occupy in them (higher among intermediate-grade non-dominant males).

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

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