For such an obscure corner of the medical literature, Cotard’s delusion is remarkably well known as the delusion that you’re dead. This was supposedly first described by Jules Cotard in 1880 but I seem to have found a description from 1576.
It’s worth noting that although Cotard’s delusion has come to represent ‘the delusion that you’re dead’, Jules Cotard’s original description was not actually that – it was a delusion of negation where the patient believed, as noted by Berrios and Luque, that she had “no brain, nerves, chest, or entrails, and was just skin and bone”, that “neither God or the devil existed”, and that she did not need food for “she was eternal and would live forever”.
In its modern use, Cotard’s delusion typically refer to the belief that you’re dead, you don’t exist, or that your body is rotting or absent. It is rare but can occur in severe psychosis.
While spending my weekend reading Basil Clarke’s book Mental Disorder in Earlier Britain (yes kids, I’m like Snoop Dogg but for out of print history of psychiatry books), I found a mention of not one but possibly two cases of Cotard delusion.
They were apparently described Levinus Lemnius’s 1576 book The Touchstone of Complexions, as Clarke recounts:
A ‘Hypochondriake person’ was unshakeably convinced that frogs and toads were eating his entrails. This was accepted, and he was given purges and enemas, the doctor slipping ‘crawlynge vermyne’ into the pot to satisfy him. A case of a man who thought his buttocks were made of glass was incomplete. Another patient had fallen into ‘such an agonie, & fooles paradise’ that he thought he was dead and gave up eating. After a week, friends came into the dark parlour in shrouds and settled down for a meal. The ‘Passioned Party’, on asking, was told that they were dead and that dead men ate and drank. ‘Straightwayes skipped this Pacient out of his Bedde and joined them.’ After supper he was given a sleeping draught.
The mention of the man who believed he had glass buttocks is also interesting as this is the glass delusion, the belief that you are made of glass and might shatter.
This was apparently common in cases of madness during the Late Middle Ages but is now virtually non-existent. Famously, it affected Charles VI of France.