Psychiatric co-morbidity in 75 patients undergoing epilepsy surgery: lack of correlation with pathological findings

BACKGROUND: Psychiatric disorders may occur in patients with intractable partial epilepsy after surgical treatment. Previous reports attributed the presence of psychological adverse events to specific pathological entities such as dysembryoplastic neuroepithelial tumors (DNETs) and gangliogliomas. The rationale for the present study is to evaluate the importance of the surgical pathology in individuals undergoing epilepsy surgery. METHODS: The patients were separated into three groups based on the surgical pathology: group I ganglioglioma (N=25), group II DNETs (N=25), and group III mesial temporal sclerosis (N=25). Thirteen of the 75 patients (17.3%) had a preexisting psychiatric disorder. The most common preoperative psychiatric diagnosis was depression (N=4). Sixty-three of the lesions (84%) were restricted to the temporal lobe. The operative strategy included resection of the lesion and epileptogenic cortex. Sixty-two of the 75 patients (83%) were rendered seizure-free. RESULTS: Eight of the 75 patients (10.7%) had an acquired psychiatric illness following surgical treatment. A mood disorder developed in three patients after surgery. No statistical difference emerged in preoperative psychiatric co-morbidity (no group difference; p=1.0) or in newly diagnosed postoperative psychiatric disease (group I vs. II, p=0.67; group I vs. III, p=1.0; and group II vs. III, p=0.67) within the three surgical pathology groups. CONCLUSION: This study indicates that the presence of psychiatric disease before and after surgery for intractable partial epilepsy, predominantly of temporal lobe origin, was independent of the pathological findings.