To answer your post, it is now well accepted historically that the ancient mysteries schools around the mediterranean sea, for example at Eleusis, used probably different methods, like isolation, incubation, method of asphyxiation, tainted beer or wine with hallucigenic natural product and not so much to create pleasurable experience like in the hippies era but for a sacred very serious methodically planned OUT OF BODY and NEAR DEATH experience or induced coma like trance for direct spiritual transformation
Spiritual experiences are non propositional real experience which are undescribeable , transcending usual discourse...
Religions are based on original experience which were denatured or forgotten or reduced to propositional dogmas oblivious of the spiritual original event...
And now for something completely different. Do you believe one can cultivate the spirit through hallucinogenic substances? Does proper intention alongside hallucinogenic ingestion create space for seeing the unseen.