Vagus Nerve Stimulation For Treatment Resistant Depression: Case Series Of Six Patients - Retrospective Efficacy And Safety Observation After One Year Follow Up

OBJECTIVE: One year observation and evaluation of the VNS (vagus nerve stimulation) efficacy and safety for patients with treatment resistant depression in Polish conditions. METHODS: An open label, uncontrolled and one center retrospective study of VNS therapy was implemented with stable pharmacotherapy in 6 patients with treatment resistant depression (TRD). For the first 3 months, only VNS parameters were altered but the pharmacological treatment was unchanged and in the following 9 months, medication and VNS dosing parameters were altered according to the clinical state of the patients. RESULTS: The baseline 24-item Hamilton Depression Rating Scale (HAMD-24) score averaged 24. Both response (>50% reduction in baseline scores) and remission rates after 3 months of treatment were only 40%. After 1 year of VNS therapy, the response rates increased to 86%. Most frequent side-effects were voice alteration (86% at 3 months of stimulation) and headaches (40%). CONCLUSION: VNS treatment was safe and effective in TRD patients and its efficacy increased with time. Efficacy ratings are similar to the previously reported studies using a congenial protocol.