Event-related potentials in methamphetamine psychosis during an auditory discrimination task. A preliminary report.

Auditory event-related potentials (ERPs) during a syllable discrimination task were recorded from 15 patients suffering from methamphetamine (MAP) psychosis after the remission of acute psychotic symptoms, and from 15 normal age-matched controls. Subjects were instructed to press a button in response to the target syllables applied to one designated ear. In MAP psychotics, the attention-related negative components (Nd) area was reduced and P300 latency was delayed compared with normal controls. MAP psychotics and controls did not differ significantly in P300 amplitude. These findings suggest that MAP psychotics show some impairment in the auditory information processing.