Phencyclidine abuse mimicking head injury.

Phencyclidine hydrochloride (PCP) is a psychoactive drug that in small doses produces agitation, excitement, and disorientation, but in larger doses results in stupor, convulsions, coma, and death. Two accident victims under the effects of phencyclidine were in coma. A history of phencyclidine abuse was not initially available in either instance. Head injury was suspected in both patients, although their neurological symptoms suggested a state of sensory blockade. Phencyclidine abuse should be considered in all patients with atypical coma despite a clear history of trauma.