4. Cotard Delusion
The Cotard Delusion is essentially The Walking Dead, but only for the sufferer. Basically, sufferers of Cotard Syndrome are convinced that they are, in fact, dead. This is usually despite the fact that they have just walked into the doctor's office and told them all of this. The delusion sometimes goes along with some other strange beliefs, often involving missing organs, melting skin or even being born without a brain. In 2005, an Iranian man turned up at the hospital saying that he was dead (standard), but that he had also been turned into a dog (a bit of a surprise). He also thought that his three daughters had suffered a similar fate, but they had turned into sheep (definitely not standard). To top it all off, he said that his relatives had tried to poison him (for...being dead I guess?) but he was safe because God was protecting him, even in death. You'll be pleased to learn that many of his symptoms were alleviated with some good, old-fashioned electro-convulsive therapy.