The author describes the 12-year history of a functional (endogenous) psychosis in a 25-year-old woman and the subsequent full social remission. The central symptom in the case history is the delusion that the patient has already lived through this life once. This delusion appears as the experience of reduplication, differing from that of déjà vu, based on mental automatism. It is accompanied by euphoria and the distortion of the future time perspective. The hypothesis of a disorder in the function of the limbic system arises as a possible pathophysiological explanation. Schizophrenic symptoms were absent and no defect was formed. This previously unknown syndrome presented by the use of the idiographic method may contribute to the widening of nomothetic nosological research.