In psychiatry, depersonalization (or derealization) is the experience of feelings of loss of a sense of reality. A sufferer feels that they have changed and the world has become less real — it is vague, dreamlike, or lacking in significance. A sufferer is divorced from both the world and from their own identity and physicality. Often times the person who has experienced this disorder claims that life "feels like a movie, things seem unreal, or hazy." Also a recognition of self breaks down (hence the name). When a person suffers from the disorder (or the symptoms associated with the same) he or she finds that when he or she looks in the mirror that his or her face is not familiar though logically he or she is completely aware of his or her identity.

The condition is usually found in conjunction with other mental disorders, especially depression, post-traumatic stress disorder or certain neuroses. If reported together with more serious delusions, depersonalization is a sign of schizophrenia — an indication of the disintegration of personality. A sufferer from depersonalization can be especially susceptible to suicide, undertaking the suicidal process calmly and easily without real awareness.

The DSM-IV categorizes depersonalization disorder as a form of dissociative disorder.

The symptoms associated with depersonalization have a known connection with psychological trauma. However, if the problem develops into a disorder (persistent and recurring) then it is important to have it treated as it may lead to suicide, depression, lack of meaning, lack of joy, and general apathy.

Lt. Col. Dave Grossman, in his book On Killing, suggests that military training artificially creates depersonalization in soldiers, suppressing empathy and making it easier for them to kill other human beings.

See also

• Alienation
• Anomie
• Dissociation

Existentialists use the term in a different context. The treatment of individuals by other people as if they were objects, or without regard to their feelings, has been termed depersonalization. Determinism has been accused of this. See also objectification.

R. D. Laing used depersonalization to mean a fear of the loss of autonomy in interpersonal relationships by the ontologically insecure.