From The Art and Popular Culture Encyclopedia
Derealization (DR) is an alteration in the perception or experience of the external world so that it seems strange or unreal. Other symptoms include feeling as though one's environment is lacking in spontaneity, emotional colouring and depth. It is a dissociative symptom of many conditions, such as psychiatric and neurological disorders, and not a standalone disorder. It is also a transient side effect of acute drug intoxication, sleep deprivation, and stress.
Depersonalization is a subjective experience of unreality in one's sense of self, while derealization is unreality of the outside world. Depersonalization and derealization are often used interchangeably, although evidence suggests they have distinct neurobiological mechanisms. Chronic derealization may be caused by occipital–temporal dysfunction.
These symptoms are common in the population, with a lifetime prevalence of up to 74% and between 31 and 66% at the time of a traumatic event.