In a previous report7 the administration of phencyclidine hydrochloride, a chemical compound with anesthetic and sedative properties, was shown to produce profound disturbances in reaction time, motor learning, and weight discrimination. These findings were obtained with normal subjects who had been given subanesthetic doses of the drug. The degree and pattern of drug-produced deficits closely approximated those found in a group of chronic schizophrenic patients given the same battery of tests without drugs. These psychotomimetic effects could not be attributed solely to the drug's hallucinogenic or to its sedative properties, since other drugs with each of these properties (lysergic acid diethylamide [LSD-25] and amobarbital sodium) produced neither the degree nor the pattern of deficits demonstrated under phencyclidine hydrochloride. It was tentatively concluded that the deficits seen in normal subjects under phencyclidine hydrochloride and in chronic schizophrenia might be attributable to a common underlying