The ancient cultures believed that mental illness and abnormality is a work of evil that is why treatments such as trephination and exorcism were performed during those ancient times. Trephination is the drilling of a hole in the skull so that the evil spirit can escape from the skull. But nowadays, trephination is only performed when there's a swelling of the brain. Exorcism, on the other hand, is the practice of expelling evil spirits through torture and chanting.