Can animals develop depression? Extrapolating mental disorders to animals but based on human criteria is something that may not be entirely accurate.
However, it has been possible to see behaviors in animals that would coincide with psychopathology that, until now, was diagnosed in humans.
The question is very complex, and we are going to deal with it below, trying to provide a well-documented answer as to whether it is possible for animals to suffer from depressive symptoms.
Is it possible for an animal to develop depression?
In the same way that human beings can present a wide repertoire of psychological problems, which have a negative impact on our well-being, it has been seen that many animals, especially mammals, can also suffer from psychopathology.
However, The study of animal psychopathology is a very complex issue, without being able to say with a resounding “yes” that animals suffer from mental disorders. The reason for this is that the conception of current mental disorders has been based on what is understood by being a human being adjusted in vital aspects such as family, social relationships, work/studies, and so on. These aspects, as can be understood, are not all of them found in other species.
So, since Depression is understood as a set of human symptoms based on criteria, also human How is it possible to diagnose it in other animals? The DSM and ICD criteria can be helpful in trying to give a diagnostic label to an animal, but we can never ignore the fact that this diagnosis would not be exhaustive or completely accurate for the ‘patient’ to whom it has been given.
Taking all this into account, in the following sections we are going to try to give a better explained answer as to why animals can have depression, but always keeping in mind that the way in which depressive symptomatology is seen in non-human animals should be considered provisional.
Animals and humans: can they be compared?
Human beings have a wide repertoire of behaviors. Some of them are healthy, providing us with well-being and a correct social adjustment, while others are harmful to us, bringing us all kinds of psychological problems, or caused by an underlying psychological problem.
Trying to see whether or not animals have mental disorders and, especially, depression, is something really complicated, since the researcher who carries out the study that addresses this issue will not be able to separate himself from his human conception of psychopathology. Interpreting depression in animals will always be done, whether we like it or not, from a human perspective
Despite how difficult it is to extrapolate human mental disorders to animals, it is curious how most of the research on psychopathology has been done based on animal models. The idea behind this type of research, which usually takes an evolutionary view, is that the brain mechanisms seen in humans are also shared in other species. This would mean that neurological problems in animals could be replicated in humans.
It is difficult to think that there are animals that can have depression but, ironically, many antidepressant drugs have been tested in animals, seeing how brain structures homologous to ours function in the absence or presence of neurotransmitters such as dopamine and serotonin, involved in depression.
Many neurologists and neurosurgeons, such as Philip R. Weinstein, maintain that many brain structures are shared by several vertebrate species, especially among mammals These structures perform, in the vast majority of cases, similar functions. Among them, the brain of several species of primates, such as chimpanzees, is especially notable.
The case of animals in captivity
When studying depression in other species, the most studied have been animals that have been raised in captivity, especially in places where they have had limited space, have suffered abuse and have not been able to perform behavior typical of their species in wild state.
The debate over animal experimentation is as hot a topic as the existence of zoos and circuses Researchers, for better or worse, have animals at their disposal with which they can carry out situations such as sensory deprivation, forced separation and food limitation. Although all animal experimentation is done for a purpose and must pass an ethical committee
However, one situation in which ethics is conspicuous by its absence is in animal shows, especially in circuses and zoos with few scruples. This should not be interpreted as a generalization, since we are not saying that abuse is committed towards them in all shows with animals. Zoos carry out impeccable species conservation work in most cases, and many circus companies are releasing their animal actors.
Unfortunately, many of the animals in these types of places suffer mistreatment, They are subjected to tough training that entails great physical, psychological and emotional stress and this causes deep wounds in their mental health, which will end up manifesting in the form of behavioral problems, depression and anxiety.
However, and regardless of whether there is mistreatment or not, what must be understood about these animals is that they are not found in their habitat. They do not develop in the same way as animals belonging to the same species in the wild. This means that, unable to show their true nature, confined to a few square meters, they are forced to reserve their energies, which sooner or later will emerge to the surface in very varied forms.
Due to this, and especially in very abused animals, which end up exhibiting unhealthy behaviors, such as self-harm, pulling out hair or feathers scratching until blood comes out, in addition to appearing apathetic, with acquired helplessness and nervousness.
How do you know if an animal is depressed?
When we talk about depression in animals, many people have the preconceived idea that the symptoms associated with this mood disorder will manifest in a more or less similar way in all species. This is not like this. In the same way that animals have different plumage and fur, eat very varied things and play a different role in the food chain, their depressive behaviors will also be variable depending on the species.
However, It has not been possible to study all the animal species in the world, and the idea that certain species, such as corals or barnacles, can have depression as we understand it behaviorally is also not conceivable. Most of the research has focused on mammals, especially chimpanzees and pets such as dogs and cats.
Within the field of primatology, although many apes have shown abilities to learn human language that are far superior to those of other animals, it must be said that their linguistic skill is limited. It does not allow them to reveal their internal world, a fundamental aspect in diagnosing depression with people, since it is important to know how they experience their problems.
Most researchers with chimpanzees use observation to understand their mental health. While observing them, they pay attention to their social behavior, their sexual interest, what their motivation is when it comes to food if they decide to face a potentially life-threatening threat, if they become separated from the group and if their sleep patterns have been altered without an apparent environmental cause.
An example of depression in chimpanzees is the case of Flint, a chimpanzee who was studied by primatologist Jane Goodall in the Gombe National Park of Tanzania and who can be read in her book Through a window (1990).
Flint lived with his mother until she died. Since then she began a period of mourning, isolating herself from the rest of the chimpanzees and staying still looking into infinity, eating absolutely nothing. She kept looking toward the horizon, hoping that her mother would return. Meanwhile, she gradually became weaker until she finally died from starvation.
Leaving chimpanzees aside, we move on to pets, especially dogs. Veterinarians often see dogs who display all kinds of behaviors when their owners leave home, showing separation anxiety, crying, howling, and behaving very impulsively They have also seen self-harm, such as scratching themselves until they bleed and slamming the door so violently that they hurt themselves. There are even dogs who, when depressed, start hunting imaginary flies.
As for cats, when they are very depressed they do just the opposite of dogs: they remain still, motionless, afraid to make any movement.
