I hate to say it, but self diagnosing a psychological problem and finding a cure for yourself could only be a continuation of the psychological problem and being in denial. It is always best to get a professional's opinion if there really and truly is a problem.
I do think that I benefit from taking a natural mood enhancing supplement called Sam-E and I have seen great improvement. I also read the Bible and do yoga for inner peace.
It is definitely not something I would consider psychological.
I'd really have a good, long, sit down chat with your cousin to determine if intervention is needed. Like mentioned before, blending the wrong kind of herbs can do more harm then good.
I have a friend that now lives in Vietnam that blended some completely harmless herbs that he took orally for some time, until he decided to smoke it, (not saying your cuz did or will) but he now thinks he lives in a video game, spiders are taking over the world, and he only communicates with people who have a blue halo over their head.