Smaller Auditory P300 Amplitude in Schizophrenics in Remission

The P300 event-related potential (ERP) was recorded using the auditory oddball paradigm in 12 (6 male) schizophrenic (DSM-IIIR) patients in rigorously defined clinical remission. The ERP was also recorded in 10 (5 male) age-, sex- and education-matched control subjects. ERP latencies and amplitude were measured at Cz and Pz recording sites. Mean latencies of the P300 in schizophrenic patients in remission at Cz [343.6 +/- 31 (SD) ms] and Pz (346.15 +/- 30 ms) did not differ from those of normals (Cz: 332.8 +/- 23 ms, Pz: 323 +/- 38 ms). The P300 ERP amplitude was significantly (p < 0.05) smaller in schizophrenics in remission at both Cz (9.2 +/- 4.4 microV) and Pz (8.8 +/- 4.4 microV) than in normals (Cz: 13.3 +/- 2.90 microV; Pz: 12.71 +/- 4.18 microV). The significance of the smaller auditory P300 amplitude in schizophrenia is discussed.