I can say that they say not to take St. John's Wort with SSRIs or other antidepressants. In Germany, you need a prescription to get St. John's Wort.

St. John's Wort is reported to help remedy mild to moderate depression. Take SJW at an appropriate dose (perhaps 900mg per day, 2 capsules in the morning, 1 in the evening (assuming each capsule has 300mg SJW); or as high as 1800. You should probably talk with a pharmacist or doctor before going that high, though). Also, make sure the SJW you're using has at least 0.3% hypericin. If it does not, adjust the dose appropriately. Give SJW six weeks before proclaiming it unsuccessful. SJW may not help in the treatment of major depression.

For me, SJW was reported to work very well with Type 3 ADD. In the book, Healing ADD, SPECT scans (brain activity scans) show that SJW has a definite positive effect on the brain activity of someone with Type 3 ADD. So I can only speak from that perspective, but I imagine it would help someone who has an anxiety disorder as well.

I should say that my experience is that, your thoughts don't automatically change. You can still come up with negative thoughts, though for me, they don't just come out of the blue, and they don't concern just about everything I experience (any more!). With SJW, for the first time I feel "Okay" all the time. And I feel Okay whenever I want to: I can stop negative ruminations and re-focus on other things, and actually enjoy those "other things." Like, if I notice I'm pondering on some negative thought, I can just stop, and read a book, and be content again. It's like someone teaching you how to ride a bike: at a certain point, you realize they have let go of the bike, and that you are fully capable of biking on your own.