Depersonalization/ derealization is a dissociative disorder, defined in the DSM-IV as “persistent or recurrent experiences of feeling detached from, and as if one is an outside observer of, one’s mental processes or body.
‘feeling like one is in a dream’
Thus it is the experience of feeling a detachment from their sense of selves and their reality (depersonalization), or their perception of the world (derealization).
It is characterised by emotional numbness and a disruption in self-awareness.
Depersonalization disorder can co-occur with a range of other mental and physical disorders.
However, it is when the symptoms are experienced persistently and recurrently, independently of other mental (schizophrenia, panic disorder) or physical disorders (epilepsy) that it is considered a disorder.