Glass delusion

The glass delusion is an external manifestation of a psychiatric disorder recorded in Europe mainly in the late Middle Ages and early modern period (15th to 17th centuries). People feared that they were made of glass “and therefore likely to shatter into pieces”. One famous early sufferer was King Charles VI of France who refused to allow people to touch him, and wore reinforced clothing to protect himself from accidental “shattering”.

Concentration of the glass delusion among the wealthy and educated classes allowed modern scholars to associate it with a wider and better described disorder of scholar's melancholy.

Robert Burton’s The Anatomy of Melancholy (1621) touches on the subject in the commentary as one of many related manifestations of the same anxiety: “Fear of devils, death, that they shall be so sick, of some such or such disease, ready to tremble at every object, they shall die themselves forthwith, or that some of their dear friends or near allies are certainly dead; imminent danger, loss, disgrace still torment others, &c.; that they are all glass, and therefore will suffer no man to come near them; that they are all cork, as light as feathers; others as heavy as lead; some are afraid their heads will fall off their shoulders, that they have frogs in their bellies, Etc.”

Miguel de Cervantes based one of his short Exemplary Novels, The Glass Graduate (Spanish: El licenciado Vidriera, 1613) on the delusion of the title subject, an aspiring young lawyer. Thomas Rodaja fell into a grave depression after being bedridden for six months after being poisoned with a purportedly aphrodisiac potion. He claimed that, being of glass, his perceptions are clearer than those of men of flesh and demonstrated by offering witty comments. After two years of illness, Rodaja was cured by a monk; no details of the cure are provided except that the monk was allegedly a miracle-maker.

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