Regression (psychology)
In psychoanalytic theory, regression is a defense mechanism involving the reversion of the ego to an earlier stage of psychosexual development, as a reaction to an overwhelming external problem or internal conflict. Sigmund Freud invoked the notion of regression in relation to his theory of dreams (1900) and sexual perversions (1905), but the concept itself was first elaborated in his paper "The Disposition to Obsessional Neurosis" (1913).