Søren Kierkegaard said this quote

Hence it is a superficial view (which presumably has never seen a person in despair, not even one’s own self) when it is said of a man in despair, He is consuming himself. For precisely this it is he despairs of, and to his torment it is precisely this he cannot do, since by despair fire has entered into something that cannot burn, or cannot burn up, that is, into the self.