"Cotard's syndrome", a description of two cases. Delusion of negation in melancholia versus delusion of negation in paranoia.

In 1880, Jules Cotard described a set of delusions in the form of negations that later became his eponymous syndrome. Cotard's syndrome is an uncommon condition characterised by the presence of nihilistic delusions in which the person thinks that "they are dead or that the world no longer exists". This document describes two cases in which a broad and enriching semiology is evidenced from a descriptive point of view, which allows us to review them together with Cotard's syndrome in the light of modern psychiatry. The first case corresponds to a depressive disorder and the other occurs in the context of a non-affective psychotic disorder. A review of the literature is presented from what Cotard described until the current psychiatric classifications.