Oh my. From the BBC: The people who think they are made of glass.

The “glass delusion” is an extraordinary psychiatric phenomenon in which people believe themselves to be made of glass and thus liable to shatter. It peaked centuries ago but there are still isolated cases today, writes Victoria Shepherd.

The late medieval French King Charles VI was one of the most notable sufferers of glass delusion. He was reported to have wrapped himself in blankets to prevent his buttocks from breaking.

Instances of the delusion cropped up in medical encyclopaedias from across Europe. There were references in fiction – most notably Cervantes’ short story The Glass Graduate of 1613, in which the hero is poisoned by a quince intended as an aphrodisiac but which instead triggers a glass delusion. [continue]

Better than thinking one’s skin is covered with bugs, I guess.