Just in case there are others diagnosed on the multiaxal scale and the DSM IV TR ..the DSM IV TR labling says -

Diagnostic criteria for 300.6 Depersonalization Disorder

A. Persistent or recurrent experiences of feeling detached from, and as if one is an outside observer of, one's mental processes or body (e.g., feeling like one is in a dream).
B. During the depersonalization experience, reality testing remains intact.
C. The depersonalization causes clinically significant distress or impairment in social, occupational, or other important areas of functioning.
D. The depersonalization experience does not occur exclusively during the course of another mental disorder, such as Schizophrenia, Panic Disorder, Acute Stress Disorder, or another Dissociative Disorder, and is not due to the direct physiological effects of a substance (e.g., a drug of abuse, a medication) or a general medical condition (e.g., temporal lobe epilepsy).

Diagnostic criteria for 300.12 Dissociative Amnesia

A. The predominant disturbance is one or more episodes of inability to recall important personal information, usually of a traumatic or stressful nature, that is too extensive to be explained by ordinary forgetfulness.
B. The disturbance does not occur exclusively during the course of Dissociative Identity Disorder, Dissociative Fugue, Posttraumatic Stress Disorder, Acute Stress Disorder, or Somatization Disorder and is not due to the direct physiological effects of a substance (e.g., a drug of abuse, a medication) or a neurological or other general medical condition (e.g., Amnestic Disorder Due to Head Trauma).
C. The symptoms cause clinically significant distress or impairment in social, occupational, or other important areas of functioning.

Diagnostic criteria for 300.13 Dissociative Fugue

A. The predominant disturbance is sudden, unexpected travel away from home or one's customary place of work, with inability to recall one's past.
B. Confusion about personal identity or assumption of a new identity (partial or complete).
C. 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 (e.g., a drug of abuse, a medication) or a general medical condition (e.g., temporal lobe epilepsy)
D. the symptoms cause clinical significant distress or impairment in social, occupational, or other important areas of functioning.

Diagnostic criteria for 300.14 Dissociative Identity Disorder

A. The presence of two or more distinct identities or personality states (each with its own relatively enduring pattern of perceiving, relating to, and thinking about the environment and self).
B. At least two of these identities or personality states recurrently take control of the person's behavior.
C. Inability to recall important personal information that is too extensive to be explained by ordinary forgetfulness.
D. The disturbance is not due to the direct physiological effects of a substance (e.g., blackouts or chaotic behavior during Alcohol Intoxication) or a general medical condition (e.g., complex partial seizures). Note: In children, the symptoms are not attributable to imaginary playmates or other fantasy play.

I have not found derealization in the DSM IV TR as of yet. it may be a newer labling than my DSM IV TR book.