You might want to invest in this book then. It's a really good read. It's about Rick Strassman, a research psychiatrist, and the research studies he did on the effects of DMT in humans. The most curious part of it is that the chemical is naturally occuring in all living things, including humans, in the pineal gland, which is thought to be by many old civilizations where the spirit resides. It's really interesting because many of his volunteers had similar experiences of being in the presence of ..entities, guides, etc. whatever you want to call it, as well as possible parallel universes. Too much to explain on here, but definitely a great read for anyone who's interested in it!