Mental illness is sometimes obvious and easily diagnosed, but in rare cases, psychological and neurological disorders are so strange that they're almost unbelievable. The brain is a staggeringly complex organ capable of surprises that science can't explain even after centuries of study. Some mental disorders strike such a tiny fraction of the population that there's virtually no research available, meaning neither their cause nor their cure are known.
These rare mental illnesses can be so singular and perplexing that they weren't even accepted as legitimate disorders until recently. Some change the way language is used and perceived. Other unusual disorders do the same to vision or motor skills. And some are so bizarre that they alter a patient's accent or make them believe they're an entirely different species. Sufferers of these illnesses can lose control of their limbs, see afterimages everywhere, think their loved ones are imposters, and - in one inexplicable case - are made violently ill by the sound of one TV news anchor's voice.This list of the weirdest mental disorders takes you on a tour of the strange side of psychiatric science with some of the rarest and least-understood mental disorders that have ever afflicted humans. These brain disorders are so unique that you may never have heard of them and may even not believe them at first, but all of these diseases are totally real.