Objective: Pathological self-mutilation-the deliberate alteration or destruction of body tissue without conscious suicidal intent-was examined both as a symptom of mental disorders and as a distinct syndrome. Methods: Data from more than 250 articles and books were reviewed, as well as data obtained by the authors from their extensive clinical experience in treating self-mutilating patients. Results and conclusions: The diverse behaviors that constitute pathological self-mutilation can be categorized into three basic types: major-infrequent acts that result in significant tissue damage, usually associated with psychoses and acute intoxications; stereotypic-fixed, rhythmic behavior seemingly devoid of symbolism, commonly associated with mental retardation; and superficial or moderate-behavior such as skin cutting, burning, and scratching associated with a variety of mental disorders. The authors propose that a syndrome of repetitive superficial or moderate self-mutilation should be regarded as an axis I impulse disorder. In most cases, the syndrome coexists with character pathology.