Déjà vu refers to a state wherein a person feels certain (cognitive judgment) that he or she has previously seen or experienced something that is actually being encountered for the first time. Sigmund Freud believed the feeling corresponded to the memory of an unconscious daydream.

The term first appeared in a French translation of the Psychopathology of Everyday Life (1901b) as part of the discussion of the superstition that can be associated with this mysterious feeling. Freud quotes certain "psychologists," without specifying who they are. The concept falls squarely within the framework of the paramnesia extensively described by psychiatrists in France, primarily Wigan (1844) and Valentin Magnan (1893), who described systematic delirium accompanied by the illusion of doppelgängers, J. Capgras (1923), who described the illusion of doppelgangers, and Pierre Janet (1905), who described cases of false...