Depersonalization also might be a symptom of other disorders, including some forms
of substance abuse, certain personality disorders, seizure disorders, and certain other brain diseases.
Depersonalization disorder is one of a group of conditions called dissociative disorders. Dissociative disorders are mental illnesses that involve disruptions or breakdowns of memory, consciousness, awareness, identity, and/or perception. When one or more of these functions is disrupted, symptoms can result.