Risk factors for postoperative depression in 150 subjects treated for drug-resistant focal epilepsy

Objective. The primary goal was to identify risk factors for post-surgical depression in subjects operated on for drug-resistant epilepsy. Secondary goals were to confirm the high rate of depression in subjects suffering from epilepsy (prior to surgery) and to look for first post-surgical depressive episode. Methods. Case series study of 150 subjects surgically treated for partial epilepsy (side of surgery: 72 right, 78 left; site of surgery: 97 Unilobar Temporal, 17 Unilobar Frontal, 14 Posterior, 22 Multilobar). All subjects routinely had three psychiatric evaluations: before surgery (baseline) and at 6 and 12 months after surgery. Psychiatric diagnoses were made according to DSM-IV-TR criteria. Bivariate (Fisher exact test and Kruskal-Wallis rank sum test) and multivariate (logistic regression model fitting) analyses were performed. Results. Thirty-three (22%) subjects had post-surgical depressive episodes, 31 of them in the first 6 months. Fourteen out of 33 experienced depression for the first time. Post-surgical depressive episodes are not associated with gender, outcome on seizures, side/site of surgical resection, histological diagnosis, psychiatric diagnoses other than depression. Depressive episodes before surgery and older age at surgery time are risk factors for post-surgical depression (p = 0.0001 and 0.01, respectively, at logistic regression analysis). No protective factors were identified. Conclusions. Our data show that lifetime depressive episodes and older age at surgery time are risk factors for post-surgery depression. Moreover, a prospective study could be useful in order to assess whether depression is really a consequence of surgery.