Effect of age and global function score on schizophrenic p300 characteristics

The relationship between function level and P300 has long been ignored and awaits clarification. Further, previous Western studies have discussed the trait/state markers of schizophrenic P300; this has not been assessed for an analogous Chinese population. P300 was recorded and compared in 153 schizophrenic patients and 101 normal controls. Reduced and delayed P300 was demonstrated for the schizophrenic group. Regression analysis was performed to determine the factors contributing to P300 amplitude and latency variation. Global Assessment of Functioning score and age had a significant influence on P300 latency prolongation. Amplitude decrement was not affected by age, duration of illness, education, psychotic status, antipsychotic dosage, or function level. Our results were grossly concordant with analogous Western reports and provided evidence that function level is an important variable contributing to P300 latency change in Chinese schizophrenics. Besides, the effect of gender on P300 amplitude was noted in normal population.