Very interesting anecdotal evidence! I know Stan Grof was quite into clinical study and this is something I think we need much more of; one would think India's universities​ would be all over these phenomena​ but I'm not seeing that they are. William James, The Varieties of Religious Experience, is still a very useful resource. One of my Gnostic leanings is an idiosyncratic nondual version which of course is quite rare as Gnosticism historically is premised on dualistic metaphysics. Peace:)