The FDA approved the VNS Therapy System by Cyberonics, Inc. in July 2005 as an adjunctive long-term treatment for adults with chronic or recurrent treatment-resistant major depression (those who have not had an adequate response to at least four courses of conventional antidepressant treatments).

The FDA's post approval requirements include post approval studies - one study will follow 1000 patients receiving VNS therapy for five years. Click here to view the FDA's approval letter.

VNS Therapy has been in use in the U.S. since 1997 as an adjunctive treatment of difficult-to-control epilepsy. Some of these patients (being treated for epilepsy) have reported improvement in mood, alertness, and memory. These benefits may be due to improved seizure control or may be a direct result of VNS therapy - or a combination of both.

VNS Therapy has been approved for use in Europe and Canada for treatment-resistant depression since 2001.

What is VNS Therapy?

VNS therapy involves stimulating the vagus nerve, which in turn stimulates brain. The vagus nerve extends from the brain through the neck to the major organs - a major communication link between the brain and body.

A small battery-powered device (a pulse generator) similar to a pacemaker is surgically implanted in the chest, connected by a lead to electrodes that connect to the left vagus nerve in the neck. The device sends small periodic electrical pulses to the vagus nerve, which delivers these electrical pulses to the brain. The pulse generator can be programmed externally by a computer, and can be turned off with a special magnet.

How Does VSN Therapy Relieve Depression:

It is not known exactly how VNS therapy relieves depressive symptoms in some people. Stimulating the vagus nerve and the brain through the vagus nerve may trigger the brain to release mood-regulating neurotransmitters or alter the way in which they are transmitted.

How Effective is VNS Therapy for Major Depression?

It appears that up to a third of people implanted with a VNS Therapy system have significant reductions in symptoms of depression.

The results from a 2- year U.S. clinical study involving 200 people showed VNS therapy significantly reduced the symptoms (at least 50% improvement in depressive symptoms) of depression in up to 30 percent of patients – about half of this group of responders had full or nearly full remittance of symptoms. Many patients who had good results within the first year were still benefiting at 2 years.

There is no way to predict which patients will respond to VNS therapy and it may take several months before any benefits become evident. Some people may not benefit at all, and some may even get worse. There are risks and side effects and special precautions must be taken.

Side Effects:

The most common side effects of VNS therapy are hoarseness of voice, cough, tickling in throat, neck pain, shortness of breath, sore throat, and difficulty swallowing. The side effects generally occur during the stimulation periods (which usually are programmed to occur 30 seconds every 5 minutes). Side effects tend to lessen over time. However, some side effects may continue, especially hoarseness of the voice. Hoarseness of voice (the most common side effect of VNS therapy - experienced by over half of patients) often continues for the full length of VNS therapy.

Risks:

As with any surgery, there is a risk of infection. There is also a small but serious risk of the device malfunctioning, which could damage the vagus nerve and lead to permanent complications. If a patient suspects that the pulse generator is not working right or is experiencing severe symptoms (intense neck pain, hoarseness, trouble breathing, etc.) a special magnet (that the patient should carry with them) can be placed over the device to turn it off.

PRECAUTIONS:

VNS Therapy system may interfere with other implanted devices such as cardiac pacemakers.

If a person with a VNS therapy device needs an MRI, special precautions must be taken. A person with a VNS stimulator should not have a full body MRI.

A person with a VNS therapy device cannot have diathermy. This includes short-wave diathermy, microwave diathermy, or ultrasound diathermy (diagnostic ultrasound is safe). Diathermy is a therapy (often used by physical therapists) used to treat pain, stiffness, etc, in which a device is applied externally to deliver energy into a person’s body.

Diathermy may cause any part of the VNS therapy system to heat up and cause temporary or permanent damage to tissue, nerves, or blood vessels – even if the VNS therapy device is turned off. If there is damage to blood vessels, death could occur.

Any part of the system is subject to overheating from diathermy. Even if the pulse generator is removed, the lead (small wires) and electrodes attached to the vagus nerve may be left in place (to avoid damaging the vagus nerve) and special precautions must still be taken.

Click here for the Depression Patients Manual for the VNS Therapy^TM System by Cyberonics, Inc.

For more information go to vsntherapy.com.

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