I've definitely known animals that were a little crazy (shout out to Francis, my boyfriend's cat, who likes to do some incredibly odd things on top of sleeping humans). But can cats and other animals actually experience mental illnesses? According to the BBC, yes: New evidence suggests that at least some animals can experience mental disorders like anxiety, depression, and even PTSD. These disorders can show themselves through symptoms that are similar to what humans with those conditions go through — picking at hair or feathers, refusing food, or having a panic attack.
Scientists have both observed this behavior in animals — for instance, they have seen military dogs show trauma-like symptoms like nervous shaking after their time in a war zone — and looked at the physical effect of mental illnesses on animals. Apparently, a mutation on a certain type of gene that both vertebrates and invertebrates possess is to blame for a lot of predilection animals have for mental illness — which means that even animals with relatively simple nervous systems, like honeybees or octopi, can experience mental illnesses. Evidence of more complex mental illnesses like schizophrenia have been found in the genes of dolphins and non-human primates.
As the BBC points out, this means the popular conception of mental illness is really flawed:
It's still common to see mental illness branded as a form of weakness. We struggle to understand that people with severe depression or anxiety cannot simply "get over it", any more than a person could will themselves to survive a heart attack.
But far from being something limited to pampered modern humans, mental illness can strike many kinds of animals and seems to have been around for hundreds of millions of years. Just like seemingly more physical disorders like cancer, it can be traced back to mechanical things such as genes and proteins within our cells.
So far, scientists have noticed these symptoms in animals that are kept as pets (like dogs, cats, and birds) or captured animals (like elephants and chimps), but wild animals may be able to experience these symptoms aswell. Animal behavior expert Marc Bekoff, for instance, told the BBC he's observed a wild coyote that seemed to experience a type of autism. But most wild animals don't seem to exhibit these traits, leading animal experts to wonder if they are killed off quickly, or simply ignored by humans. Both options: really sad.
By the way — I do love burgers and bacon, but does the idea that animals can get mental illnesses make anyone else feel uneasy about eating meat?