Can animals have mental illness?

The health of the mind has been traditionally 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 on an emotional level.

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

Dispossessing 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 where they are susceptible to it (livestock, industry, etc.).

In this article, we will abundant the empirical evidence that allows us to give an answer to the simple question of can animals have mental illness? The purpose of the text is to better understand how they suffer from emotional distress and what situations precipitate it.

In recent years society has refined its sensitivity to the subjective experience of animals, so that there is even a scientific specialty (Animal Psychopathology) aimed at studying this phenomenon. In the present 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 decreased ability to feel pleasure (anhedonia), resulting from a perceived significant loss. It is one of the great disorders of our time, and there is evidence 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 ethical safeguards in laboratories were more lax than they are today. These investigations tried to explore the negative affective reactions of a living being when experiencing adverse circumstances over which it had no control.

Models were sought to generalize any findings to man, with the aim of extracting environmental risk factors that could predict the decline of his mood. In these studies, a dog was usually placed inside a special cage, at the base of which were located two separate metal surfaces, which covered the entire length of the cage.

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

After several trials, the researcher would apply the electrical 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 find a place where his discomfort would end, but when the absence of viable options was confirmed, he would adopt a despondent 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 one, not only was evidence obtained on how depression is triggered in humans, but it was 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 “rituals” of farewell when a member of their herd dies . In fact, there is evidence that not only are they aware of the finiteness of their organism, but also that they have rules regarding what is considered “good” or “bad”, adapting these notions to the sphere of life and death (seeking the former and fearing the latter).

These animals go through a mourning process when faced with the loss of a loved one, in much the same way as has been described in classical models for humans. They may resort to physical spaces in which to care for the remains of those who preceded them (“cemeteries” near rivers where the corpses of dying elephants that tried to drink in their last rales are accumulated), and even show behaviors that suggest they are dealing affectively with absence (such as reduced food intake, sleep disturbance, etc.).

3. Suicide

There is evidence from marine mammals (such as dolphins) that may make the decision to take their own lives under certain circumstances , both in the wild and in captivity.

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

The research carried out on this subject leads to two different conclusions: that the dolphin’s autolithic behaviour is due to a 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 behaviour analogous to the one that can be observed in the human being , when the 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 objected that rats and mice show a preference for water mixed with substances such as cocaine, or simply with sugar (which is a natural enhancer), 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 itself before the stimuli that facilitate survival (sex, food, etc.), generating pleasure (elevated hedonic tone) and increasing the motivation for them. The effect of the drug would alter its alostasis and reduce the search for what was once rewarding, so it would end up completely dominating the animal’s behavior.

5. Anorexia of activity

With studies like this one, not only was evidence obtained on how depression is triggered in humans, but it was 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 “rituals” of farewell when a member of their herd dies .
In fact, there is evidence that not only are they aware of the finiteness of their organism, but also that they have rules regarding what is considered “good” or “bad”, adapting these notions to the sphere of life and death (seeking the former and fearing the latter).

These animals go through a mourning process when faced with the loss of a loved one, in much the same way as has been described in classical models for humans.
They may resort to physical spaces in which to care for the remains of those who preceded them (“cemeteries” near rivers where the corpses of dying elephants that tried to drink in their last rales are accumulated), and even show behaviors that suggest they are dealing affectively with absence (such as reduced food intake, sleep disturbance, etc.).

3. Suicide

There is evidence from marine mammals (such as dolphins) that may make the decision to take their own lives under certain circumstances , both in the wild and in captivity.

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

The research carried out on this subject leads to two different conclusions: that the dolphin’s autolithic behaviour is due to a 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 behaviour analogous to the one that can be observed in the human being , when the suicide is motivated by a state of very intense organic or emotional pain.

4.
Addictions

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 itself before the stimuli that facilitate survival (sex, food, etc.), generating pleasure (elevated hedonic tone) and increasing the motivation for them.
The effect of the drug would alter its alostasis and reduce the search for what was once rewarding, so it would end up completely dominating the animal’s behavior.

5.
It has also been observed that social and environmental isolation can lead to self-injurious actions in many animal species, especially primates and birds, which can harm themselves when caged or isolated from the environment (in socially poor spaces). Common self-injurious actions involve scratching and biting of different parts of the body, as well as plucking of feathers in birds.

Conclusions

Animals are susceptible to emotional problems , especially when they are taken 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 profound 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.

Can animals have mental illness?