It doesn't, entirely. But, there are plenty of people (perhaps most?) who put a lot of faith in what their physicians say, and are, frankly, afraid of not taking the advice and prescriptions given to them. I'm not in that category, but I once was, so I can easily see how it happens. And, it can be very difficult to "fight" the system, especially for someone who is battling an illness, be it physical or psychiatric.