Depersonalization is a classic response to acute trauma, and may be highly prevalent in individuals involved in different traumatic situations including motor vehicle accident, and imprisonment.
Psychologically depersonalization can, just like dissociation in general, be considered a type of coping mechanism. Depersonalization is in that case unconsciously used to decrease the intensity of unpleasant experience, whether that is something as mild as stress or something as severe as chronically high anxiety and post-traumatic stress disorder. The decrease in anxiety and psychobiological hyperarousal helps preserving adaptive behaviors and resources under threat or danger. Depersonalization is an overgeneralized reaction in that it doesn't diminish just the unpleasant experience, but more or less all experience – leading to a feeling of being detached from the world and experiencing it in a more bland way. An important distinction must be made between depersonalization as a mild, short-term reaction to unpleasant experience and depersonalization as a chronic symptom stemming from a severe mental disorder such as PTSD or dissociative identity disorder. Chronic symptoms may represent persistence of depersonalization beyond the situations under threat