https://en.wikipedia.org/wiki/Depersonalization
This article is about the psychological symptom. For the diagnosis, see depersonalization disorder.

Depersonalization (or depersonalisation) is an anomaly of self-awareness. It consists of a feeling of watching oneself act, while having no control over a situation.[1] Subjects feel they have changed, and the world has become vague, dreamlike, less real, or lacking in significance. It can be a disturbing experience, since many feel that, indeed, they are living in a "dream". Chronic depersonalization refers to depersonalization disorder, which is classified by the DSM-IV as a dissociative disorder. Though degrees of depersonalization and derealization can happen to anyone who is subject to temporary anxiety/stress, chronic depersonalization is more related to individuals who have experienced a severe trauma or prolonged stress/anxiety. Depersonalization-derealization is the single most important symptom in the spectrum of dissociative disorders, including dissociative identity disorder and "dissociative disorder not otherwise specified" (DD-NOS). It is also a prominent symptom in some other non-dissociative disorders, such as anxiety disorders, clinical depression, bipolar disorder, schizophrenia,[2] borderline personality disorder, obsessive-compulsive disorder, migraine and sleep deprivation, and it can be a symptom of some types of neurological seizure. It can be considered desirable, such as in the use of recreational drugs.