A Study on the Effect of Risperidone on PPI and P50 Deficit in First-Episode and Chronic Patients with Schizophrenia

Objective To investigate the effect of atypical antipsychotics risperidone on prepulse inhibition of the startle reflex(PPI) and P50 deficit in first-episode and chronic patients with schizophrenia. Methods PPI and P50 were tested and compared in 81 first-episode acute schizophrenia patients and 92 chronic schizophrenia patients before and after the risperidone. Results There was no significant difference in PPI and P50 indices between the two groups before treatment(P>0. 05); 2) there was no significant correlation between PPI & P50 inhibition indices and PANSS score, onset frequency and disease course(P>0.05); 3) Except the significant group main effect for S2 amplitude in P50(P=0. 02), there was no significant change for main effect and interaction of the other P50 and PPI inhibition ratio indices after treatment(P>0. 05). The effect of risperidone on PPI and P50 measurement index had nothing to do with the curative effect. Conclusion There exists a deficit in sensory gating inhibition in both first-episode schizophrenia and chronic schizophrenia, which is relatively independent from disease course. The risperidone is not effective in improving PPI and P50 inhibition deficit.