A lot of us in corporate America, including me, suffer from mild anxiety disorder. I've been taking Lexapro (newer version of Celexa) for about a year, and it helps. I wonder, however, if a lot of anxiety results from carrying a jumble of hundreds of things to do in our head, and if a more natural remedy would be following GTD.
I certainly don't mean to imply that there aren't lots of people out there with real physiological reasons for taking anxiety/depression medication. But I'd guess that there are a number of people who just need a system like GTD. An analogy would be someone who takes weight loss drugs, rather than adopting a healthy diet, to lose 25 pounds.