Sadistic personality disorder is a diagnosis which appeared only in an appendix of the revised third edition of the American Psychiatric Association

American Psychiatric Association

The American Psychiatric Association is the main professional organization of psychiatrists and trainee psychiatrists in the United States, and the most influential worldwide. Its some 38,000 members are mainly American but some are international...

's Diagnostic and Statistical Manual of Mental Disorders

Diagnostic and Statistical Manual of Mental Disorders

The Diagnostic and Statistical Manual of Mental Disorders is published by the American Psychiatric Association and provides a common language and standard criteria for the classification of mental disorders...

 (DSM-III-R). The current version of the DSM (DSM-IV) does not include it, so it is no longer considered a valid diagnostic category. The diagnosis Personality disorder not otherwise specified may be used instead. However, the disorder is still studied for research purposes.

Causes (etiology)

There appears to be a genetic component to the disorder.