We constantly read about autism rates, schizophrenia rates, depression etc in the human world. And many of us think we can identify stress or depression in zoo animals, or even our pets on occasion. But have there ever been any studies into serious mental illnesses in animals?

What would happen to a chimapnzee suffering from schizophrenia in the wild? Are these just human diseases or is it likely monkeys, horses, cows, hedgehogs etc also suffer from psychoses or neuroses?