Depersonalization, which designates a feeling of unreality and alienation of the self, is nosologically unspecific and occurs in mild to severe psychopathology. Psychoanalysts conceive of it as a defense phenomenon and emphasize ego splitting and self-observation, disturbance of the sense of reality and of the sense of self, and the role of unacceptable identifications. While in neurotically structured patients, depersonalization may be utilized by the ego as a defensive affect protecting the ego from painful superego stimuli and contradicting identifications, in developmental pathologies it may be a signal affect denoting an actual or feared challenge to self-constancy.