Dissociative Identity Disorder...is initially a useful coping response to an environment which is very difficult to endure. The problem is that dissociative responses-such as switching, blanking out, or going into a trance-become automatic, and, once the original abusive environment has been left behind, are of little use in life and may be detrimental.
Elizabeth Howell, Knowing, Not-Knowing and Sort-Of-Knowing: Psychoanalysis and the Experience of Uncertainty
child-abuse, dissociation, dissociative-identity-disorder