Question: What is the effectiveness of newer treatments like vagal nerve stimulation (VNS), transcranial magnetic stimulation (TMS), and deep brain stimulation (DBS)?
Answer: The mainstay of treatment for depression these days really is medication. We do know however that there are limits to the effectiveness of medication. The first medication that we try is likely only to get somebody well about 30 percent of the time, and somebody may need to go through a whole series of treatments for depression before they can eventually get well. We do know that in the long run that somebody stands about an 80 to 85 percent chance of recovering from their depressive illness with medication. But this can get more and more difficult as time goes on.
For this reason, we're looking at some more aggressive types of treatment for depression, and some of these involve brain stimulation. One approach which has been approved by the FDA is called vagal nerve stimulation, where electrodes are implanted into a nerve in the neck, the vagus nerve. And we have found that over the span of months through stimulation of the vagal nerve that a number of individuals with depression can get somewhat better. Right now, vagus nerve stimulation is not a stand-alone treatment -- it's something that is given to individuals along with medication, it's something that can be a secondary therapy for the treatment of depression which has proved resistant to other kinds of treatment.
There are some other types of brain stimulation, however, that are being studied. One is transcranial magnetic stimulation, where instead of passing electricity through the brain as one can do with electroconvulsive therapy, one can place a device on the outside of the patient's head that puts a magnetic pulse into the brain, and appears to show promise as a treatment for depression. This however is still in the experimental stages of development.
Another more invasive treatment is called direct brain stimulation where electrodes are put directly into the brain. This is something which again has been shown to be effective in some individuals with depression. Actually, the treatment was originally developed on patients with Parkinson's disease where it has been approved by the FDA, and for the more advanced cases of Parkinson's disease has been shown to be effective. Some of those patients with Parkinson's disease were noticed in fact to become less depressed after brain stimulation, and that's been the source of the trials in depression itself.
This is another treatment that shows promise, and within the next couple of years, we're thinking that both of these treatments may be approved for use in the treatment of depression.