I really dont believe in drugs, to be frank. But, there have been certain documentaries that deal with hallucinogens regarding spirituality, such as Ayahusca or however its spelled. So it does raise the question, if a drug can take you back to your birth, then couldn't you gain some spirit communication abilities in the return?
Personally, Im working through Book of Spirit Communications by Raymond Buckland, which is fair in my opinion. Not too fluffy. Exercises abound.
Therefore, no need for hallucinogens for me, but interesting to ponder.