Most people being treated for depression with VNS won't respond in the first month or two. It typically takes 3 to 4 months to see results.
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Question: What are the typical results of Vagus Nerve Stimulation? Mark S. George: You got to remember that the people that we have tried in the trials have failed everything else. So, there by definition, not going to response. So if we were to give them a new drug like Prozac, we would get a 0% response. So in, this is the group that has been tried in. in that group, if you look at six months, after they have had the device in at six months, one third of people are much, much better, almost cured. Another third are substantially better. Their symptoms have been cut in half. There is another third, in whom it doesn't work. One of the bits of research that we are doing here is to try it out, figure out before we put the device in who is going to respond. So that we don't have people going to all the trouble of putting it in and then feeling disappointed. But it's about a third, third, third great results, a third with reasonable results and then a third in which it's not doing much good. The other thing about the response that's very interesting about this, compared to medications is, a lot of time people who respond to a medication like Prozac and don't get better, the depression will go away for three or four months and then it comes back. We don't know how that is and it's unfortunately pretty common. So is it the brain gets resistant to that medicine, figures out a way to outsmart it. the brain becomes tolerant to it. This device and the patients that we have studied so far, does not seem to show tolerance. if you are better with this thing at six months, you got greater than a 90% chance of being better five years later. So, it seems to have been remarkably durable, the affects that we see so far, which is very interesting. With VNS, most people won't respond in the first month or two. It's really a three or four months before people get better. As I said before, once they get better, they are very likely to stay well. So, it's a different kind of a treatment than drugs, takes much, much slower to get better, but once you are there its much more durable. That is also an interesting science question, why is that, why is it slower but more durable and is it the case that things that are quick and -- but it does take a little bit longer. So, people have to be patient to wait.