양성 및 음성 정신분열증 환자의 P300 및 P300과 우울증상，인지기능과의 관계

The P300 of Positive and Negative Schizophrenic Patients, and the Relationships of P300 with Depressive Symptom and Cognitive Function

Objects : It is well known that the changes of the P300, one of the event related evoked potential, are closely related to cognitive function. This study is on the relationships of the amplitude, latency of the P300, depressive symptom and cognitive function. Methods : Thirty schizophrenic patients(l8 positive and 12 negative schizophrenics), diagnosed by DSM-IH-R, who were on treatment care at Chonnam University Hospital comprises the patient group. Age and sex matched thirty normal persons were chosen as controls. All subjects had undergone Oddball procedure by auditory stimuli and their amplitude and latency of P300 were measured. The cognitive function was estimated by Choice Reaction Time Test and Digit Symbol Substitution Test and the depressive symptoms, by BDI and Depression subscale of SCL-90-R. Results : The P300 latency of the patient group showed marked delay to that of the controls, especially in negative schizophrenics. And the P300 amplitude of patient group was much lower than that of the control group, but there was no significant inter-patient group difference. A profound negative correlation with peak-to-peak amplitude of P300 and depressive symptoms was found, but no significant correlation with baseline-to-peak amplitude and latency of P300 was observed. The P300 latency delay was negatively correlated with the Digit Symbol Substitution Test Scores and positively with the Choice Reaction Time Test Scores. The peak-to-peak amplitude of the P300 was positively correlated with Digit Symbol Substitution Test Scores, negatively with Choice Reaction Time Test Score. But this study tells no significant correlation of baseline-to-peak amplitude with cognitive function test scores. Conclusion : The latency delay and amplitude reduction of P300 were pronounced in the schizophrenics. And especially the negative schizophrenics showed significant latency delay. These result is consistent with the poor performance ability of the schizophrenic group, especially for the poor cognitive function of the negative one. Therefore the authors suggest that the amplitude and the latency, especially the latency, of the P300 could be useful indices for decreased congnitive function of schizophrenic patients.