Unusual diagnoses among violent patients.

Several medical disorders rarely cause violent behavior. When they do so, it is dramatic because the violence and other bizarre behaviors are not in keeping with the premorbid picture of the individual. Often, medical and neurologic symptoms are present, but occasionally psychiatric symptoms may present alone with the aggression and violence, which points out the importance of complete medical psychiatric evaluations of patients who present with recent histories of violent behavior. Most violence involves "horses," but the rare "zebras" should be kept in mind because they are often treatable.