Substance-induced dissociative disorders and psychiatric nosology.

Transient amnesias, fugues, twilight states, automatisms, depersonalization, and furors or explosive disorders can occur in association with, or be caused by, various medications or substance-induced organic brain states. Agents capable of precipitating dissociative-like states include alcohol, barbiturates and similarly acting hypnotics, benzodiazepines, scopolamine, clioquinol, beta-adrenergic blockers, marijuana and certain psychedelic drugs, general anesthetics, and others. The presentations of substance-induced dissociative states may resemble those of functional dissociative disorders, or organic and psychogenic dissociative factors may coexist and be intertwined or indistinguishable. Organic dissociative states are distinct from intoxication, amnestic disorder, frank delirium, or other organic mental disorders as specified in DSM-III and DSM-III-R, yet these diagnostic manuals have no inclusive category or coherent nosological approach to dissociative states not strictly psychogenic in etiology. Substance-induced and other organic dissociative disorders can have clinical, medicolegal, and neuropsychological significance. They provide a unique opportunity for the study of mind-brain relationships and should be included in psychiatric nosology.