When my doctor first prescribed Prozac I decided to take St John's Wort instead because I thought it was more 'natural'. I took it for about 6 months and I think it helped in some way, but I had a really bad experience with it when I ran out of supplies one day. I was in South America and couldn't find a pharmacy that sold it - and after a couple of days without it I felt TERRIBLE. My anxiety hit me with a vengeance and I thought I was going to go completely insane! I could barely function until I got home and bought some more.
So...I then decided to go back to the doctor, who prescribed Paxil. I stopped the St John's Wort and started the Paxil and have been on it ever since. I believe that for me St John's Wort and Paxil are both effective, but that the side effects/withdrawal from St John's Wort are just as bad as those with Paxil. And I feel more comfortable taking something that's prescribed and monitored by my doctor.
Guess everyone's different though!
Bunty