Impact of Adjunctive VNS on Drug Load, Depression Severity, and Number of Neuromodulatory Maintenance Treatments

Erhan Kavakbasi; Helen Bauermeister; Lars Lemcke; Bernhard T Baune

doi:10.3390/brainsci14020159

Impact of Adjunctive VNS on Drug Load, Depression Severity, and Number of Neuromodulatory Maintenance Treatments

Brain Sci. 2024 Feb 4;14(2):159. doi: 10.3390/brainsci14020159.

Authors

Erhan Kavakbasi¹, Helen Bauermeister¹, Lars Lemcke², Bernhard T Baune^{1

3

4}

Affiliations

¹ Department of Psychiatry, University Hospital Münster, University of Münster, 48149 Münster, Germany.
² Department of Neurosurgery, University Hospital Münster, University of Münster, 48149 Münster, Germany.
³ Department of Psychiatry, Melbourne Medical School, The University of Melbourne, Melbourne, VIC 3052, Australia.
⁴ The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC 3052, Australia.

Abstract

Vagus nerve stimulation (VNS) is a long-term adjunctive treatment option in patients with difficult-to-treat depression (DTD). A total of n = 20 patients (mean age 52.6 years) were included in the multicenter, prospective, observational, naturalistic RESTORE-LIFE study and were treated with adjunctive VNS as an add-on to treatment as usual. Exploratory and secondary outcome parameters from a single center were investigated for this present analysis. The overall mean drug load slightly decreased from 4.5 at baseline to 4.4 at 12 months (Z = -0.534, p = 0.594). The drug load was lower in previous electroconvulsive therapy (ECT) responders than in non-responders. There was a reduction in the mean number of hospitalizations per month after VNS implantation (Z = 1.975, p = 0.048) and a significant decrease in the mean Montgomery Åsberg Depression Rating Scale (MADRS) score from 27.3 at baseline to 15.3 at 12 months (T = 4.230, degree of freedom (df) = 19, p = 0.001). A history of ECT response at baseline was associated with greater improvement in the MADRS score after 12 months of VNS (F = 8.171, p = 0.013). The number of neuromodulatory maintenance treatments decreased during the follow-up period. In summary, there was an alleviation in the burden of illness among DTD patients treated with VNS.

Keywords: difficult-to-treat depression; electroconvulsive therapy; esketamine; medication load; treatment-resistant depression; vagus nerve stimulation.

Grants and funding

All participants were included in the RESTORE-LIFE study (ClinicalTrials.gov Identifier: NCT03320304). This study was sponsored by LivaNova, the manufacturer of the VNS devices implanted in the patients. The authors’ institution received fees for study visits of the RESTORE-LIFE study. The present analysis was based on data from a single center. LivaNova supported during drug load calculation. LivaNova had no influence on the preparation or completion of the manuscript. This research received no other external funding.