depersonalization disorder
Depersonalization disorder is marked by periods of feeling disconnected or detached from one's body and thoughts (depersonalization). The disorder is sometimes described as feeling like you are observing yourself from outside your body or like being in a dream. However, people with this disorder do not lose contact with reality; they realize that things are not as they appear. An episode of depersonalization can last anywhere from a few minutes to many years. 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.