For me, the realisation that mental illness – and the capacity to recover from it – is something we share with other animals has been comforting news. When we feel our most anxious, compulsive, scared, depressed or enraged, we’re also revealing ourselves to be surprisingly like the other creatures with whom we share the planet. As Darwin’s father told him, “There is a perfect gradation between sound people and insane… Everybody is insane at some time.” And as with humans, so with everyone else – animals included.
An undergraduate professor, John Crook—a wise and enlightened Buddhist—used to talk to us about the evolutionary survival benefits of emotions. He wrote the book on the evolution of consciousness. It doesn't start and end with humans. In the book The Feeling of What Happens, Antonio Damasio describes a continuum: animals first developed instinctive, emotional reactions (reptilian brain), then they evolved to experience inner feelings around those emotions (mammalian brain), followed by an ability to have knowledge of those feelings, to think about them (human brain).
Along with emotions and feelings emerges the possibility of animals developing mental health problems. There are dogs who are anxious, narcissistic, schizoid. Paranoid dogs, OCD dogs, psychotic dogs. Dogs that were abused as puppies and suffered lifelong post-traumatic stress. I know a dog called Daisy, a lovely rescue from Battersea Dogs' Home, who sometimes gets the blues. Peter Singer argues that we all have a responsibility to examine the amount of suffering that we are directly or indirectly responsible for, or complicit in—that's the yardstick. It's hard to live ethically, but we do what we can. Humans are at their best when they're being humane. We need to treat animals with great care, especially our fellow mammals. Partly to save them, and partly to save ourselves.
Bridging the animal-human divide works both ways. We are animals, too, and we forget that at our peril. So often our human brain takes over and tries to rationalize away emotions or deny them, or repress them, to overrule our reptilian and mammalian brains, with unfortunate results. InWaking the Tiger, Peter Levine writes that by cutting ourselves off from our "primitive, instinctual self, humans alienate their bodies from their souls." As a result, we exist "in a limbo in which we are neither animal nor fully human." Ignoring our animal responses is akin to taping over the warning lights on the dashboard of your car. Eventually you blow a gasket, run out of fuel, or your engine melts down. The car stops. Time to call a breakdown service and get help.