VNS uses electrical impulses to stimulate centers in the brain that regulate mood, sleep, appetite, and motivation. It has been approved by the FDA for the treatment of chronic or reccurring depression or bipolar disorder since July 2005, and for the treatment of refractory epilepsy since July 1997.
VNS treats the brain directly with subtle electrical stimulation. It is something like a “pacemaker for the brain.” A battery-operated, computer-controlled device called a pulse generator—about the size of a pocket watch—is surgically implanted in the upper chest, just below the collarbone. Wires attach the device to the left vagus nerve, which travels from the brain down through the neck and to several of the major organs. Electric signals travel from the generator to the vagus nerve. When stimulated, the nerve sends signals up to the brain.
Pros and Cons
VNS is known to affect blood flow to different parts of the brain, but we do not yet know exactly how it works to alleviate the symptoms of depression. However, research studies have shown that VNS Therapy significantly helps around 30 % of patients who have been treated for chronic depression or type II bipolar affective disorder. The therapeutic effects appear to accumulate over time, and some patients may need 12 months of treatment to see a full effect. If a patient feels an improvement by 12 months, research shows that he or she has almost a 70% chance of keeping that positive response after two years. Patients using VNS Therapy often continue to require some medication, but studies have shown that, for some people, the variety and quantity of medications may be reduced over time.
VNS can help those patients who have not found adequate relief from depression with any other treatment method. It can improve their mood, sleep, energy, motivation, and overall quality of life. Patients treated with VNS have a low relapse rates for depressive episodes.
VNS does not cause the side effects encountered with many medications, such as sexual dysfunction, memory loss, sleep difficulty, and weight gain. VNS does have some side effects, but patients often find that these relatively minor effects decrease with time. During the 30-second stimulation, patients may experience temporary voice changes and hoarseness, difficulty swallowing, tightness in the throat, increased muscle tension, difficulty breathing with exertion, headache, nausea, neck pain, numbness and tingling at the incision site, coughing, dizziness, chest pain, and/or a sore throat. A very small percentage of patients experience vocal cord paralysis while the device is stimulating the nerve. Although uncommon, VNS Therapy may lead to hypomanic or manic states in bipolar patients.
VNS is not a quick fix, and it is not a cure for depression. Patients may not feel any effect for several months. VNS Therapy is considered long-term, and while many patients may require less medication, they may still need some drug therapy o keep their depression in control. Some patients may have no improvement or get worse with VNS Therapy. The treatment does require surgery and is more invasive than other treatments for depression.
What does the therapy involve?
The VNS system is implanted in an outpatient surgery, and most patients go home the same day. The surgery typically lasts only 1 or 2 hours, and involves two small incisions: one in the upper chest area, where the pulse generator is placed, and another on the left side of the neck, where the wires are attached to the vagus nerve. Because the incisions are small, they typically heal with very little visible scarring.
A week or two after the surgery, the doctor will turn on the stimulator during an office visit, and will gradually adjust the strength of stimulation over several weeks. The stimulator is programmed to deliver intermittent electrical impulses to the nerve throughout the whole day. Stimulation lasts for 30 seconds and occurs every 5 minutes. Sometimes this is noticeable as a tickling sensation or slight hoarseness to the voice. Patients are supplied with a magnet to temporarily turn off the device if they find that the period stimulation disrupts them when they are participating in particular activities, such as giving a speech, singing, or exercising heavily.
Once the device is implanted, it is meant to be permanent and automatic. After several years, batteries need to be replaced, which involves another short outpatient surgical procedure. Although the pulse generator can be removed, the wires remain permanently attached to the vagus nerve.
Who should consider VNS?
The US Food and Drug Administration has approved VNS Therapy for adult patients (18 years and older), who have long term, chronic depression that has lasted two or more years, or recurrent and severe depression, or depression that has not improved after the use of other treatments.
VNS is not for everyone. In order to be a candidate for VNS, patients must have tried at least four different medication therapies for depression, from two different classes (which means that the medications must have at least two different mechanisms of action in the body’s chemistry). These should also include at least two forms of augmentation therapy, a combination of two medications which act differently when they are taken together, such as buproprion and fluoxetine. These treatments must have been tried for a significant length of time, using an appropriate dosage.
We also recommend that patients have had an adequate course of evidence-based psychotherapy for depression, such as Cognitive Behavioral Therapy (CBT) or Interpersonal Therapy (IPT). We strongly encourage patients to try an adequate course of Electroconvulsive Therapy (ECT) before considering VNS.
Some psychiatric conditions exclude patients from consideration for VNS therapy, including acute suicidal thinking or behavior, rapid cycling bipolar disorder, schizophrenia, schizoaffective disorder, severe personality disorder, and ongoing substance/alcohol abuse.
The vagus nerve is associated with several major organs, so some medical conditions exclude patients from receiving VNS Therapy. These include: previous brain injury, progressive neurological disorders, severe lung disorders, vasovagal syncope (a fainting syndrome), ulcers, dysautonomias (imbalance of the autonomic nervous system), and heart arrhythmias (irregular heartbeat). VNS therapy can cause or worsen obstructive sleep apnea. Patients who have had one or both vagus nerves removed are not candidates for VNS.
If you think you are a candidate for VNS treatment, speak with your psychiatrist, or call our program for more information. You may benefit from a 2-3 hour consultation with us about VNS or other treatment options for chronic depression. Please call us at 1-800-525-5188 or 734-764-9190. A social worker will take a brief history of your symptoms, gather insurance information, and answer your questions about setting up the consultation. So that we can help you most effectively, please provide us with a history of all the treatments you have tried for depression, including medications, psychotherapy, and electroconvulsive therapy. Then we will schedule you for a consultation with our professional staff. You may also want to consider other brain stimulation techniques used by our Psychiatric Neuromoduation Program in the treatment of chronic depression, such as electroconvulsive therapy. Also, research studies are underway with newer techniques and you may qualify for one of those protocols. Please ask when you call.