In the long history of strange mental disorders, glass delusion ranks as one of the most baffling. It appeared for the first time around 1400, and people suffering from glass delusion were convinced that their bodies were made of glass. Charles VI of France, the glass delusion king, may have been the first to suffer from the fear that his body could shatter.
Glass delusion was also known as scholar’s melancholy because it almost always struck wealthy, educated Europeans – the same group that had the resources to buy glass and reading glasses, which were new products in the 15th century. Across Europe, a Princess claimed she had been turned to glass, Miguel de Cervantes wrote about a scholar vagabond with glass delusion, and a glass maker believed his buttocks would shatter if he sat on a toilet.
Doctors devised extreme cures for glass delusion, including beating a man to prove he wouldn't shatter and burning the straw that one man used to protect his fragile body. Glass delusion wasn't the last of the strange mental illnesses from history– in fact, it was followed by cement delusion.