Vagus nerve stimulation is associated with mood improvements in epilepsy patients

Vagus nerve stimulation (VNS) has gained increasing acceptance for treatmen t of drug-resistant seizures. The aim of this study was to evaluate effects of VNS on depressed mood in epilepsy patients during the first 6 months af ter implantation of the stimulation device. This study was conducted as an addition to the international multisite randomized and double-blind control led trial on anti-seizure effects of VNS (EO3). Only adult patients with > 4/month medication-resistant complex-partial seizures were included (N = 11 ). During the acute phase of the study (3 months after implantation), patie nts were randomly assigned to low (stimulation detection) versus high stimu lation (maximal tolerability, maximum 1.75 mA). Mood and mood changes were recorded based on standardized psychiatric rating scales and self-report qu estionnaires. Patients were assessed 4 weeks before (baseline) as well as 3 and 6 months after implantation. Significant positive mood effects were ob served in most scales and subscales at the 3-month follow-up (P < 0.05). Mo od improvements were sustained at the 6-month follow-up and were independen t of effects on seizure activity (9/11 mood responders versus 2/11 seizure responders). Mood effects appeared more pronounced in the high stimulation group after the acute study phase, but findings were not significant (P < 0 .10). VNS is associated with mood improvements in patients with epilepsy, b ut to confirm VNS dose effects, studies with more statistical power are nee ded. (C) 2000 Elsevier Science B.V. All rights reserved.