It's good if you are only moderately depressed, for full-blown clinical depression don't use it. It takes a couple of weeks to have any effect, and it may be a placebo effect, but if it works so what.
Donna: St John's Wort has a proven track record for mild and temporary bouts of 'the lows.' I'll avoid using the word depression as if it is indeed clinical depression then this needs to be referred to a GP.
But I also wish to caution you that St John's Wort can have some serious side-effects if taken with certain other prescription medications. The concern has run so high that in some countries it has been removed from the shelves and is now only available by prescription.
As we move to the Autumn and Winter seasons, our bodies iologically slow slightly. Scientists believe this is our ancient instinct to hibernate. Light therapy and other means can work just as well as medications. I just offer this as a thought.