Rare Mental Disorders And Medical Conditions You Won't Believe Are Real 

Mike Rothschild
Updated February 28, 2020 936.5k views 18 items

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.
The pathological inability to make decisions, aboulomania causes sufferers to become gripped by “paralysis by analysis,” a kind of mental vapor lock, when faced with a choice about something, even something trivial.
Do you graze on grass? Do you moo at inappropriate times? If you’re suffering from the pathological delusion that you’re a cow, you've probably come down with a case of boanthropy. You’d be in good company, as the Biblical king Nebuchadnezzar was thought to have been in the grip of an illness that made him “eat grass as oxen.”
Mary Hart Syndrome

An incredibly specific kind of mental illness, Mary Hart Syndrome was named after the Entertainment Tonight anchor whose voice caused seizures and confusion in a woman in the early '90s. It’s likely that the seizures were caused by a something unique in Hart’s tone of voice and not anything that she specifically was saying.

Caffeine-Induced Anxiety
Coffee, as you're probably aware, elevates the heart rate, increases alertness, and generally wakes you the heck up. But if you already suffer from anxiety or an anxiety disorder, too much caffeine might just send your body and mind off on a rocket ride of stress and jumpiness.