Many of us have known a dog on Prozac. We’ve also witnessed the eye rolls that come with canine psychiatry. Doting pet owners—myself included—ascribe all sorts of questionable psychological ills to our pawed companions. But the science does suggest that numerous non-human species suffer from psychiatric symptoms. Birds obsess; horses on occasion get pathologically compulsive; dolphins and whales—especially those in captivity—self-mutilate. And that thing when your dog woefully watches you pull out of the driveway from the window—that might be DSM-certified separation anxiety. “Every animal with a mind has the capacity to lose hold of it from time to time” wrote science historian and author Dr. Laurel Braitman in “Animal Madness.”
But there’s at least one mental malady that, while common in humans, seems to have spared all other animals: schizophrenia. Though psychotic animals may exist, psychosis has never been observed outside of our own species; whereas depression, OCD, and anxiety traits have been reported in many non-human species. This begs the question of why such a potentially devastating, often lethal disease—which we now know is heavily genetic, thanks to somegenomically homogenous Icelanders and plenty of other recent research—is still hanging around when it would seem that genes predisposing to psychosis would have been strongly selected against. A new study provides clues into how the potential for schizophrenia may have arisen in the human brain and, in doing so, suggests possible treatment targets. It turns out psychosis may be an unfortunate cost of our big brains—of higher, complex cognition.
Put another way, with complicated, highly social human thought—and the complicated genetics at the root of higher cognition—perhaps there’s just more that can go wrong: complex function begets complex malfunction.
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