Can animals develop depression?Extrapolating mental disorders to animals but based on human criteria is something that may not be quite right.
However, they have been able to see behaviors in animals that would coincide with psychopathology that, until now, was diagnosed in humans.
The question is very complex, and we will deal with it below, trying to give a well-documented answer about whether it is possible for animals to suffer from depressive symptoms.
- Related article: ” What is Ethology and what is its object of study?“
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 done based on what is understood as being a human being adjusted in vital aspects such as family, social relationships, work / studies, and so on. These aspects, as you can understand, are not all of them found in other species.
Thus, 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 criteria of the DSM and the ICD can be helpful in trying to give a diagnostic label to an animal, but it can never be ignored that this diagnosis would not be exhaustive or entirely right for the ‘patient’ who has been given .
Taking all this into account, in the following sections we will try to give a better explained answer about why animals can have depression, but always keeping in mind that the way depressive symptomatology looks in nonhuman animals should considered as provisional.
Animals and human beings: 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, that bring us all kinds of psychological problems, or that are caused by a psychological problem behind.
Trying to see whether or not animals have mental disorders and, in particular, depression, is something really complicated, since the researcher who carries out the study that addresses this issue will not be able to disassociate himself from his human conception of psychopathology. Interpreting depression in animals will always be done, whether you like it or not, from a human perspective .
Despite the difficulty of extrapolating human mental disorders to animals, it is curious how most 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 come to say that neurological problems in animals could have their replica 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 as brain structures homologous to ours work in the absence or presence of neurotransmitters such as dopamine and serotonin, involved in depression .
Many neurologists and neurosurgeons, such as Philip R. Weinstein, argue 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 primate species, such as chimpanzees, is especially remarkable.
- You may be interested: ” Major depression: symptoms, causes and treatment“
The case of captive animals
When studying depression in other species, the most studied has been animals that have been bred in captivity, especially in places where they have had reduced space, have suffered abuse and have not been able to perform their own behavior in their species. wild state.
The debate on animal experimentation is a hot topic like 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 limitation of food. Although all animal experimentation is done with an objective and an ethical committee must pass
However, a situation in which ethics shines by its absence is in that of animal shows, especially in circuses and zoos with few scruples. This should not be interpreted as a generalization, since we are not saying that abuses of them are committed in all animal shows. Zoos carry out an impeccable species conservation task in most cases, and many circus companies are releasing their animal-actors.
Unfortunately, many of the animals in this type of places suffer bad treatment, are subjected to hard training that involves great physical, psychological and emotional stress , and this causes deep wounds to occur in their mental health, which will end up manifesting of behavior problems, depression and anxiety.
However, regardless of whether there is abuse or not, what should be understood about these animals is that they are not found in their habitat. They do not develop in the same way as they would animals belonging to the same species in the wild. This means that, unable to show their true nature, confined in a few square meters, they are forced to reserve their energies, which will sooner or later emerge to the surface in many different ways.
Because of this, and especially in very mistreated animals, they end up showing unhealthy behaviors, such as self-injury, tearing off their hair or feathers , scratching until blood comes out, in addition to being apathetic, with acquired helplessness and nervousness.
How to 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 more or less similarly 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 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 skills to learn human language far superior to that of other animals, it can be said that their linguistic ability is limited. It does not allow them to reveal their inner world, a fundamental aspect in the diagnosis of depression with people, since it is important to know how they live their problem.
Most chimpanzee researchers use observation to know their mental health. While observing them, they look at their social behavior, their sexual interest, what their motivation is in front of the food , if they decide to face a life-threatening threat, if they separate 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 which can be read in his book Through a window (1990).
Flint lived with his mother until she died. Since then he began a period of mourning, isolating himself from the rest of chimpanzees and standing still looking towards the infinite, without eating anything at all. He kept looking towards the horizon, hoping his mother would return. Meanwhile, he gradually weakened until, finally, he died from starvation.
Chimpanzees aside, we turn to pets, especially dogs. Veterinarians often see dogs who manifest 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 to bleed and knocking the door so violently that they are injured. There are even dogs who, being depressed, start hunting imaginary flies.
As for cats, when they are very depressed they do just the opposite of dogs: they remain still, motionless, fearful of making any movement.