2-Year Study of Vagus Nerve Stimulation for Higher-Grade Treatment-Resistant Depression: Clinical Outcomes and Policy Recommendation

The goal of this observational study is to evaluate whether vagus nerve stimulation (VNS) intervention can reduce depressive symptoms and suicidality in adults with higher-grade treatment-resistant depression (HG-TRD)-individuals who have not responded to at least four prior depression treatments. The main questions it aims to answer are: does VNS lead to a meaningful and sustained reduction in depression severity over 24 months? and does VNS reduce suicidal thoughts and behaviors in this population? Participants in this study were adults (age ≥ 18) with chronic or recurrent depression and at least four failed prior treatments, including medication, psychotherapy, electroconvulsive therapy (ECT), or esketamine. They underwent surgical implantation of a VNS device and their depressive symptoms and suicidality assessed at baseline, and then again at 6, 12, 18, and 24 months using the Montgomery-Åsberg Depression Rating Scale (MADRS). The study includes continous follow-upvisits and VNS device adjustments for 2 years post implantation. with outcomes including treatment response, remission, changes in suicidal ideation, and psychiatric hospitalization days over the study period