Fugue (also known as Dissociative Fugue) is a really interesting type of disorder in which a person suffers a bout of amnesia and then flees their home and identity. Often the person will travel far away from their home, assume a new identity, and live as a different person until they "snap" out of their amnesic state.
The DSM criteria for Dissociative Fugue are:
1. The main disturbance is sudden, unexpected travel away from home or one's customary place of work, with inability to recall one's past.
2. Confusion about personal identity or assumption of a new identity (partial or complete).
3. The disturbance does not occur exclusively during the course of Dissociative Identity Disorder and is not due to the direct physiological effects of a substance (for example, a drug of abuse, a medication) or a general medical condition (for example, temporal lobe epilepsy).
4. The symptoms cause clinically significant distress or impairment in social, occupational, or other important areas of functioning.