Effects of vagus nerve stimulation on symptoms of depression in patients with difficult-to-treat epilepsy.

PURPOSE: Vagus nerve stimulation (VNS) is well established in the treatment of epilepsy and disorders of depression. The prevalence of depression is high in patients with epilepsy, but still it remains unclear how patients with a comorbidity of epilepsy and symptoms of depression respond to VNS.

METHODS: We investigated 59 patients with different subtypes of disorders of depression as a comorbidity of epilepsy, who underwent VNS-surgery. Before and one year after VNS surgery, the severity of symptoms of depression was evaluated by a psychiatrist using Montgomery-Åsberg Depression Rating Scale (MADRS) and Beck-Depressions-Inventory (BDI). Response towards epilepsy was measured by a seizure reduction of at least 50%.

RESULTS: Symptoms of depression ameliorated in response to VNS in the overall of all patients MADRS 29 to 18 (p < 0,001) and BDI 24 to 14 (p < 0,001) and all subtypes of disorders of depression. Seizure reduction of at least 50% was achieved in two out of three of all patients two years after VNS.

CONCLUSION: We were able to show the beneficial effect of VNS in the treatment of patients with pharmacoresistant epilepsy and a comorbidity of symptoms of depression.