ABSTRACT
OBJECTIVES: Previous studies have suggested that information processing impairment is the main pathophysiology of post-traumatic stress disorder (PTSD). The P300 event-related potential (ERP) has been widely used, in diseases with cognitive dysfunction, such as schizophrenia and Alzheimer's disease, for detecting abnormality in information processing. This study examined P300 characteristics of PTSD patients. METHODS: We recruited 23 patients (mean age 44.35) who met DSM-IV criteria for PTSD and matched 24 normal control (NC) subjects by age and education level. The NC group had no personal history of psychiatric or neurological abnormality. We conducted the Korean version of the structured interview for PTSD (K-SIPS) and Davidson trauma scale (DTS) with the PTSD patients. Then we measured P300 amplitude and latency on 3 electrodes (Cz, CPz, Pz) in both PTSD patients and the NC group. RESULTS: Compared with the NC, the P300 amplitudes of PTSD patients were lower on Cz (PTSD: NC=5.51+/-2.82 uV : 11.80+/-5.18 uV, p<0.01), CPz (PTSD : NC=5.84+/-2.71 uV : 12.69+/-4.51 uV, p<0.01) and Pz (PTSD : NC=5.01+/-2.60 uV : 10.99+/-4.24 uV, p<0.01). We found increasing tendency toward P300 latency in PTSD group compared with NC. However, the BDI and DTS symptom severity scores were negatively correlated with the P300 amplitude of Pz. CONCLUSION: There was a significant reduction of P300 amplitudes in PTSD patients. Compared to NC group, PTSD patients showed a reduced P300 amplitude significantly correlated with symptom severity. The present findings suggest PTSD patients experience cognitive dysfunction and ERP P300 can be a useful surrogate marker of symptom severity in PTSD patients.