There aren't many studies on it because the drug companies won't fund them... Though the drug companies have funded the studies that say one shouldn't take st johns wort at the same time as taking an antidepressant because they have similar effects and their interaction could be harmful.

So... If you wanted to try it then you would need to come off your current med. If your current med isn't really working then I guess there is no loss...

It is important to get quality tablets where there is good dosage control. Some brands are careful about each tablet having the same dosage and other brands don't have such quality restrictions (thus the actual dosage found in different tablets can vary considerably). I don't know much more about that, or about what brands in particular, but it would be worth checking google and finding out... Same goes for what dosage...

I've known some people to really swear by it.
While others don't.
Just like any other med really...