Recurrent pulling out of one's hair resulting in noticeable hair loss.
An increasing sense of tension immediately before pulling out the hair or when attempting to resist the behavior.
Pleasure, gratification, or relief when pulling out the hair.
The disturbance is not better accounted for by another mental disorder and is not due to a general medical condition (e.g., a dermatological condition).
The disturbance causes clinically significant distress or impairment in social, occupational, or other important areas of functioning.
Criteria summarized from:
American Psychiatric Association. (1994). Diagnostic and statistical manual of mental disorders, fourth edition. Washington, DC: American Psychiatric Association.