i took SJW for about two months. i had to stop because it made me really not give a fuck. i literally had to bite my tongue to stop myself from telling a few people to fuck off. Checking the bottle of the Nature's Way brand again, it says "For maximum benefit, use for at least 2 months". Given some recent events, i've started taking it again. i'm about two weeks in and i'm starting to feel the effects.
i'd recommend you speak to a holistic doctor, or at least get some opinions from knowledgeable staff at a health food store. Keep in mind the latter is no substitute for talking to a doctor, holistic or otherwise. Also, talk to your doctor about using it. Traditional doctors usually don't know anything about holistic remedies, or will try to steer you away from them, but SJW is pretty popular in treating depression and other things, so they might have some experience with patients using it.