Vagus Nerve Stimulation in Treatment-Resistant Depression: A Case Series of Long-Term Follow-up

Abstract

ObjectivesVagus nerve stimulation (VNS) has been shown to be effective for treatment-resistant depression (TRD). However, long-term (>5 years) studies on the efficacy and tolerability of this treatment have been lacking. Here, we report a long-term clinical follow-up of 5 patients with severe and long-standing TRD, who received a VNS implant.MethodsOf the initial 6 patients with TRD implanted with VNS at our center, 5 of them were followed for 6 to 12 years after implantation. Primary efficacy outcomes were clinical response and improved functioning at follow-up visits. The primary safety outcome was all-cause discontinuation, and the secondary safety outcomes were the number and the severity of adverse events.ResultsThe VNS implant was associated with a sustained response (>10 years) in terms of clinical response and social, occupational, and psychological functioning in 3 patients. Two patients dropped out after 6 and 7 years of treatment, respectively. Vagus nerve stimulation was well tolerated by all patients, who reported only mild adverse effects. One patient, who discontinued concomitant drug treatment, had a hypomanic episode in the 10th year of treatment. The parameters of the VNS device were fine-tuned when life stressors or symptom exacerbation occurred.ConclusionsOur case series showed that VNS can have long-term and durable effectiveness in patients with severe multiepisode chronic depression, and this could be associated with its neuroplastic effects in the hippocampus. In light of good general tolerability, our findings support VNS as a viable treatment option for TRD.

Living-Neuron-Based Autogenerator

“…Notably, deep nerve stimulation has already demonstrated considerable success in treating various neurodegenerative diseases [ 61 , 62 , 63 ]. For a new vagus nerve stimulator, preliminary clinical trials are necessary to determine the device’s efficacy and safety in treating specific diseases, as well as to establish optimal stimulation parameters.…”

Self-Regulatory Neuronal Mechanisms and Long-Term Challenges in Schizophrenia Treatment

“…The anatomical and functional connectivity of the vagus nerve provides a clear basis for its effects on the CNS. Although it is most often recognized for its descending spicules to the viscera, >80% of the vagus nerve consists of afferent connections that terminate in the nucleus tractus solitarius in the brainstem [ 67 , 68 ]. Electrical stimulation of the vagus nerve stimulates cholinergic forebrain and sinusoidal noradrenergic site activity and subsequently causes the release of neuromodulators in the cortex [ 69 , 70 ].…”

Optimal psychiatric treatment: Target the brain and avoid the body

“…Newer FDA-approved neuromodulation therapies include repetitive transcranial magnetic stimulation (rTMS), which was approved for depression in 2013, obsessivecompulsive disorder (OCD) in 2018, smoking cessation in 2020, and anxious depression in 2021. 7 Vagus nerve stimulation (VNS) is used for drug-resistant epilepsy and was later approved for treatment-resistant depression, 8,9 but some studies report it can be helpful for fear and anxiety in autism spectrum disorder 10 and primary insomnia. 11 There are many other neuromodulation therapies in development 12 that have not yet been FDA approved (Table 3, page 6).…”