Vagus Nerve Stimulation (VNS)

Overview

Vagus nerve stimulation is, in many ways, the strangest member of the neuromodulation family. It requires surgery to implant, then works slowly over months, and once it's working, the benefit keeps accruing for a year or two. That profile makes it genuinely useful for a specific population — patients with chronic, markedly treatment-resistant depression who have tried most everything else — and genuinely mismatched for acute presentations where speed matters.

This page is written for both patients considering VNS and clinicians supporting or managing VNS patients. The distinction between those audiences isn't as sharp as it is for TMS or ECT; VNS is enough of a commitment that patients considering it tend to want the same level of detail their clinicians do.

What VNS is

VNS uses a small implanted pulse generator — about the size of a cardiac pacemaker — to deliver regular electrical pulses to the left cervical vagus nerve. The generator sits under the skin below the left collarbone. A thin wire (the "lead") runs from the generator, tunneled beneath the skin of the chest and neck, to the vagus nerve itself where it wraps around the nerve and delivers the stimulation.

Once turned on, the device runs continuously on a preset schedule — for example, stimulating for 30 seconds every 5 minutes, 24 hours a day. Patients don't have to do anything to activate it. The device doesn't need to be charged. The battery lasts approximately 8–10 years before requiring a minor outpatient replacement procedure.

How VNS was discovered for depression

VNS has been used for epilepsy since the early 1990s. The antidepressant effect was discovered incidentally — epilepsy patients treated with VNS reported that their mood improved as a side effect of seizure control. This led to dedicated trials for depression, and eventually to FDA approval for treatment-resistant depression in 2005.

How it works in the brain

The vagus nerve is a bidirectional information highway between the body and the brainstem. When VNS stimulates the vagus nerve, it's primarily activating afferent fibers — those that carry signals up from the body to the brain. These signals first reach the nucleus tractus solitarius in the brainstem, then propagate to the locus coeruleus, raphe nuclei, amygdala, hippocampus, and prefrontal cortex — regions involved in mood, arousal, and reward regulation.

The mechanism is thought to involve gradual changes in noradrenergic and serotonergic signaling, plus inflammation reduction and neuroplasticity effects that accumulate over months. The slow onset almost certainly reflects the fact that these are adaptive changes that take time to develop, rather than acute effects that could be measured immediately.

How VNS is different from other treatments

VNS has an unusual therapeutic profile that sets it apart from TMS, ECT, ketamine, and pharmacotherapy:

• Slow onset. Benefits typically emerge over 3–12 months of continuous stimulation, with full effect often taking 12–24 months. This is dramatically longer than any other antidepressant intervention. Patients considering VNS need to understand they are making a long-horizon decision.
• Durable response. When VNS works, the benefit tends to accumulate rather than wane. Follow-up data from the RECOVER trial showed that of patients with a meaningful response at 12 months, more than 80% maintained or increased their benefit at 24 months — and 92% of those with substantial response at one year were still benefiting at two years.
• Continuous, not episodic. Unlike TMS or ECT treatment courses, VNS is always on. There is no "index course" to complete, no tapering schedule, no maintenance sessions to schedule.
• Complementary. VNS is typically used alongside ongoing pharmacotherapy and sometimes alongside maintenance ECT or TMS, rather than as a replacement. It's additive rather than substitutive.
• One-time procedure. Unlike TMS (requires 30+ daily visits) or ECT (requires acute course + ongoing maintenance), VNS requires one surgical procedure and then background operation. The tradeoff: the procedure is surgical rather than outpatient clinical.

Who VNS is for

VNS is indicated for adults with chronic or recurrent treatment-resistant depression who have not responded to at least four adequate antidepressant trials. In practice, the typical VNS candidate has:

• Long-standing depression (years, often decades)
• Multiple failed medication trials across drug classes
• Often prior experience with ECT, with partial benefit but unable or unwilling to continue maintenance ECT indefinitely
• Capacity to tolerate a slow, uncertain response curve and continue with ongoing support while waiting for benefit

When VNS isn't the right fit

VNS is less appropriate for patients who need rapid response to acute suicidality or crisis — by the time VNS is meaningfully working, months have passed. For those situations, ECT or rapid-acting ketamine are much better fits. VNS is also not usually first-line for moderate treatment-resistant depression where TMS hasn't been tried; the cost, surgical nature, and slow timeline of VNS make it a later-in-the-sequence option rather than an early one.

Patients should also be in a position to commit to long-term follow-up. VNS isn't a procedure you get and then forget about — parameter adjustments and monitoring are part of the treatment, particularly during the first 1–2 years.

The evidence, honestly

The VNS evidence base has been complicated. It's worth walking through because both the strengths and the limitations matter.

Early evidence (2000s)

Early open-label trials in the 2000s (Rush et al. 2000, Marangell et al. 2002) showed promising response rates of 40–50% meaningful response over 12 months of treatment. These trials established the pattern that has been consistently observed: slow onset, cumulative benefit.

However, the pivotal sham-controlled RCT that led to FDA approval (Rush et al. 2005) was a 10-week short-term trial, and it did not separate active VNS from sham at that endpoint. The FDA approved VNS anyway in 2005, largely on the basis of the longer-term open-label data, but the short-term RCT's failure created a lasting credibility problem.

In 2007, CMS (Medicare) denied coverage for VNS in treatment-resistant depression, citing the 2005 RCT as insufficient evidence. Many private insurers followed CMS's lead, which is a major reason VNS has remained less-used clinically than its profile might suggest.

The RECOVER trial (2024)

To address the coverage question, CMS required a new trial — RECOVER — designed specifically to answer whether VNS works over a longer timeframe. RECOVER (Conway et al. 2024, Brain Stimulation) is the largest trial of its kind, enrolling 493 patients with markedly treatment-resistant depression (mean of 13 prior failed antidepressant trials, 70% with prior ECT or other interventional treatments) across 84 sites.

The primary endpoint was "percentage of time in MADRS response" over 12 months of comparing active VNS to sham (devices implanted in both groups, but only activated in the active arm). Over 12 months, the active-VNS group showed statistically significant and clinically meaningful improvement from baseline on multiple measures — but the trial missed its primary endpoint because the sham group also improved substantially.

Possible reasons for the surprisingly strong sham response:

• The placebo effect is known to be large in long sham-controlled depression trials
• All RECOVER participants received enhanced treatment-as-usual, which itself is more intensive than many of these patients had previously received
• A 12-month sham procedure is an extraordinary commitment that patients who volunteer for it may be especially invested in
• Trial protocols did not allow VNS parameters to be adjusted after the first 2 months (to maintain blinding), preventing the dose optimization that's standard in real-world practice

Where the evidence stands in 2026

In June 2025, LivaNova (the VNS device manufacturer) initiated the formal CMS reconsideration process to seek Medicare coverage for VNS in treatment-resistant depression. The application is based on the RECOVER data plus several follow-on publications analyzing specific secondary outcomes. The reconsideration process typically takes 12–18 months. Whether or not CMS reverses its 2007 decision will substantially affect access to VNS.

Practical considerations

The implantation procedure

VNS implantation is an outpatient surgical procedure performed by a neurosurgeon. Patients go home the same day. Details:

• Duration: Typically 1–2 hours under general anesthesia
• Incisions: Two small incisions — one below the left collarbone for the pulse generator, one in the left side of the neck for the lead attachment to the vagus nerve
• Recovery: Mild incision pain and restricted activity for 1–2 weeks; most patients return to normal activity quickly
• Surgical complication rate: Low; risks include infection, bleeding, injury to surrounding nerves or vessels. Serious complications are rare.

Activation and titration

The device is typically activated 2–4 weeks post-op to allow incision healing. At the first activation visit, initial parameters are set at a low level and gradually increased over subsequent visits based on tolerability. Most patients notice a mild sensation in the throat during stimulation (throat tightness, slight voice change, coughing). These sensations usually become less noticeable with time as the patient adapts, and parameters can be adjusted if they remain bothersome.

Device management and follow-up

Once activated, the device requires periodic check-ups by the psychiatrist or neurologist managing the patient:

• Every 3–6 months during the first 1–2 years, during which parameters may be adjusted to optimize response
• Less frequent (annually) once stable
• Visits involve interrogation of the device via an external programmer (painless, takes a few minutes), review of response and side effects, and any parameter adjustments

Side effects

The most common VNS side effects occur during stimulation and typically diminish with time or with parameter adjustment:

• Voice changes (most common)
• Cough
• Throat tightness or discomfort
• Shortness of breath with exertion during stimulation
• Infection at the implant site (uncommon, mostly early post-op)

Most side effects are mild and don't require discontinuation. Severe or persistent side effects can usually be managed with stimulation parameter adjustment (decreasing current, pulse width, or duty cycle).

Battery and device replacement

The battery lasts approximately 8–10 years depending on stimulation parameters. When the battery depletes, the pulse generator is replaced with an outpatient procedure — a smaller surgery than the original implantation, since the lead remains in place. Some patients may have multiple generator replacements over the course of decades of treatment.

Cost and insurance coverage

Device plus implantation costs approximately $25,000. Insurance coverage for VNS in depression is currently limited:

• Medicare: Limited coverage; CMS reconsideration process is active as of June 2025
• Private insurance: Variable; some insurers cover, most don't; prior authorization is almost always required
• Manufacturer programs: LivaNova has had patient assistance programs; current availability should be verified with the device rep

MRI compatibility

Modern VNS devices are MR-conditional, meaning MRIs can be safely performed with specific scanning protocols (typically head MRI at certain strengths and with certain coil types). Older VNS devices may be MR-unsafe or have more restrictive MR conditions. Always confirm the specific device model and check MR compatibility before imaging.

Where VNS fits in the neuromodulation landscape

For most patients with treatment-resistant depression, the typical sequence is:

1. Antidepressant trials across drug classes with augmentation strategies
2. Psychotherapy (typically CBT or IPT)
3. TMS (noninvasive, FDA-cleared for TRD, reasonable first neuromodulation option)
4. ECT (highest efficacy, best for severe or urgent cases) or ketamine/esketamine (rapid-acting)
5. VNS (for patients with chronic illness who've been through the above with partial or inadequate benefit)

This isn't a rigid sequence — clinical urgency, patient preference, side effect profiles, and practical considerations (insurance, geography, logistics) all shift the ordering. But the general principle holds: VNS tends to earn its place after other options have been tried, not as a first or second-line intervention.

VNS vs. maintenance ECT

A meaningful comparison for some patients is VNS versus indefinite maintenance ECT. Both are appropriate for chronic treatment-resistant depression with demonstrated ECT responsiveness. Tradeoffs:

• Maintenance ECT: Known response, faster time to effect, but requires ongoing procedures under general anesthesia, has cumulative cognitive costs, and is logistically burdensome
• VNS: Single surgical procedure then background operation, no ongoing general anesthesia, minimal cognitive burden — but slow onset and uncertain response

Some patients do well transitioning from maintenance ECT to VNS; others need both strategies concurrently; others do better continuing with maintenance ECT. The right choice depends on the patient's specific history and preferences.

Ongoing management of existing VNS patients

Patients with existing VNS devices are typically managed by their outpatient psychiatrist, with parameter adjustments and troubleshooting provided in collaboration with the VNS device manufacturer's clinical support team (LivaNova field clinical engineers). This is a routine part of the psychiatric care of VNS patients and doesn't typically require specialized neurosurgical follow-up unless there's a device complication.

If you (or your patient) has a VNS device and need ongoing management — including parameter adjustments, response evaluation, side effect management, or coordination of care — our program welcomes these patients. Contact information is at the bottom of the page, or use the general Prisma Health Neuromodulation Program contact on the home page.

References

Key primary sources for the VNS evidence base. Organized thematically.

Original approval era

1. Rush AJ, George MS, Sackeim HA, et al. Vagus nerve stimulation (VNS) for treatment-resistant depressions: a multicenter study. Biol Psychiatry 2000;47(4):276–286.
2. Marangell LB, Rush AJ, George MS, et al. Vagus nerve stimulation (VNS) for major depressive episodes: one year outcomes. Biol Psychiatry 2002;51(4):280–287.
3. Rush AJ, Marangell LB, Sackeim HA, et al. Vagus nerve stimulation for treatment-resistant depression: a randomized, controlled acute phase trial. Biol Psychiatry 2005;58(5):347–354.

Long-term outcomes

1. Aaronson ST, Sears P, Ruvuna F, et al. A 5-year observational study of patients with treatment-resistant depression treated with vagus nerve stimulation or treatment as usual: comparison of response, remission, and suicidality. Am J Psychiatry 2017;174(7):640–648.
2. Rosson S, Bresolin N, D'Avella D, et al. Vagus nerve stimulation in treatment-resistant depression: long-term clinical outcomes (10+ year follow-up). Eur Psychiatry 2021;64(Suppl 1):S737.

RECOVER trial and analyses

1. Conway CR, Aaronson ST, Sackeim HA, et al. Vagus nerve stimulation in treatment-resistant depression: a one-year, randomized, sham-controlled trial (RECOVER). Brain Stimul 2024;17(6):1295–1306.
2. Rush AJ, Sackeim HA, Conway CR, et al. Effects of vagus nerve stimulation on daily function and quality of life in markedly treatment-resistant major depression: findings from RECOVER. Brain Stimul 2024;17(6):1307–1318.
3. Sackeim HA, Aaronson ST, Conway CR, et al. Characterizing the effects of vagus nerve stimulation on symptom improvement in markedly treatment-resistant major depressive disorder: A RECOVER trial report. J Affect Disord 2025;382:244–256.
4. Durability of the Benefit of Vagus Nerve Stimulation in Markedly Treatment-Resistant Major Depression: A RECOVER Trial Report. Preprint/accepted 2025–2026 (WashU Medicine, 24-month data).

Mechanism and reviews

1. Müller HHO, Moeller S, Lücke C, et al. Vagus nerve stimulation (VNS) and other augmentation strategies for therapy-resistant depression (TRD): review of the evidence and clinical advice for use. Front Neurosci 2018;12:239.
2. Carreno FR, Frazer A. Vagal nerve stimulation for treatment-resistant depression. Neurotherapeutics 2017;14(3):716–727.