While there is plenty of anecdotal support for the longer term benefits of etheogens, the road to a better understanding of yourself and place in the universe is strewn with people hiding in their beds or under a table. The psychonaughts experience isn't exactly a piece of cake and shouldn't be taken lightly. Likewise, the 'why' of why these things help with issues like depression are obvious to any one who has taken the trip. These kinds of altered states force you to confront demons. They help you because they are >hard< and you have to deal with things. The experience helps with depression because it specifically brings to light the issues and causes of ones depression and you have to deal with them.
I'm concerned about the idea of boiling the positive benefits of something like mushrooms into a single compound.