Little is known about the effects of cocaine on cognitive tasks. Event
-related potentials (ERP) were recorded in 7 cocaine abusers during th
e performance of the auditory oddball task before and after the intrav
enous injections of saline and cocaine (60-80 mg). The P3B and slow wa
ve components of the ERP were significantly larger 60-210 min after th
e cocaine than after the placebo injection. The results suggest that c
ocaine abusers have difficulty in maintaining optimal stimulus process
ing during extended testing. Cocaine blocks this decrement in stimulus
processing.