Objective : The purpose of this study was to analyze the correlation between symptom severity and neurocognitive factors in traumatic head injury patients. In addition, the effect of frontal lobe damage on these parameters was examined. Methods : We selected 18 patients who had brain damage for the moderate to severe traumatic brain injury (MSTBI) group, and 17 patients who met the diagnostic criteria for post-traumatic stress disorder (PTSD) without the finding of brain damage for the comparison group. For the evaluation of neurocognitive function, K-WAIS, Rey-Kim Memory Test, K-FENT, WCST, and MMPI-2 were used. Results : The results of the comparison (using the malingering scale) revealed that the values of PDS and PK, which express the severity of symptoms, and the values of the validity scale F, F (B), and F (P) were significantly higher in the overly-expressed group. F (B) in overly-expressed group and PK, Pt, and Sc in the properly-expressed group had significant correlation with the severity of symptoms. F (B), S, and Stroop error inhibition in PTSD, and PK, Pt, Sc, and MQ in MSTBI had significant correlation with the severity of symptoms. The results of the comparison based on the finding of frontal lobe damage revealed that PDS, EIQ, and MQ ware significantly higher in the group without brain damage. Conclusions : It was revealed that each neurocognitive factor was correlated with the severity of symptoms. There was a decrease in complaints or symptoms reported by the frontal lobe injury group, and this is believed to be due to degenerative change in the personality and emotional functioning of these patients following frontal lobe damage.