P50 SUPPRESSION IN RECENT-ONSET SCHIZOPHRENIA - CLINICAL CORRELATES AND RISPERIDONE EFFECTS

Chronic schizophrenic patients often do not suppress the auditory P50 component of the event-related potential to the second of 2 clicks, pr esented 500 ms apart, suggesting a loss of normal inhibition. This stu dy attempted to replicate the P50 suppression deficit in patients with recent-onset schizophrenia and to examine whether P50 is related to c linical symptoms or is affected by an atypical antipsychotic medicatio n. Data from 22 recent-onset schizophrenia patients and 11 normal cont rols revealed that disruption in P50 suppression is present during the early stages of illness. In addition, impaired P50 suppression covari ed with clinical ratings of anxiety, depression, and anergia; results also suggested that the P50 inhibitory deficit may be related to the d egree of patients' attentional impairment. Finally, risperidone, compa red with a typical antipsychotic medication, improved inhibition of P5 0 to the second click. These results support P50 suppression as a meas ure of disordered neurocognition in schizophrenia.