Abnormal photic driving responses in never-medicated schizophrenia patients.

The present study was conducted to compare electroencephalogram (EEG) driving responses to 10 hertz photic stimulation in 14 drug-naive schizophrenia patients and 16 sex- and age-matched control subjects. The amplitude of photic driving responses (PDRs) recorded from the occipital region was significantly lower in schizophrenia patients than in controls. In eight schizophrenia patients (vs. none in the control group) the PDR amplitudes recorded at the frontal region were higher than those at the occipital region, and frontal to occipital PDR ratios were significantly larger in schizophrenia subjects than in controls. Quantitative analysis of the resting EEG showed that the patients also had a significantly lower amplitude for the alpha frequency band. These findings suggest that the PDRs of schizophrenia patients are abnormal in their amplitude and distribution.