Where we don’t know what’s going on, it’s best not to speculate. Especially about things like schizophrenia or mind-altering drugs. Not everybody who talks to gods is, not to put too fine a point on it, out of their minds.
Intense religious experiences are something that one is primed for – but my personal experience says that study, world view, beliefs, ritual, group bonding, and imagination are sufficient.
I’ve read books by chaos magicians suggesting a drug trip as a rapid shortcut. I’ve also read warnings against that by others. I can see some sense in either approach and I think it just depends on the person.
The group I was part of required you to be clean, sober, and in a good emotional state to participate in anything, and it worked for us.
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I think some people assume there’s a whole IMAX 3D extravaganza to religious/mystic/occult experiences, but it tends to be a lot more subtle. Though sometimes startling or unsettling, and occasionally pretty hilarious.
Outside of a ritual context, there is not one experience I can name that a skeptic couldn’t easily dismiss as coincidence. Some of those had pretty deep emotional resonance regardless. But I think the gods love plausible deniability 
(I won’t speak of experiences inside of ritual context.)