I'll never forget a patient I saw on a psychiatry rotation, early in my training. A 20-something man was brought in by EMS. His family said he was demon-possessed. He'd never had any prior mental problems, but for no obvious reason began having episodes of hearing voices, shouting, screaming, and thrashing his arms and kicking his feet as if he were fighting off an attacker. When not talking incoherently, he'd be howling or barking like a dog. The family pastor knew he was seriously possessed and had prayed over him repeatedly. At first, he seemed to quiet down and was less physically combative. But in the last day, he was just lying in bed with his eyes open, not eating or drinking, incontinent of urine, moving very little, and not responding at all. That's when they called EMS. One look at him and it was obvious this man had a severe acute psychotic break, and was now catatonic and dehydrated. And within several hours after some IV fluids and a single injection of Haldol, he rejoined the world. He sat up, began talking and answering questions coherently, and was soon eating, drinking coffee, and walking about the ward. I remember this so clearly because it was the most incredible turn-around I'd ever seen. Demon possession, if not being fabricated, is mental illness. I can't imagine that if demons really existed, they'd be chased off so quickly by a major tranquilizer.