I think it had an effect, but it is possible that, through meditation, he had already achieved similar states of mind and become adept at controlling/navigating

I think it had an effect, but it is possible that, through meditation, he had already achieved similar states of mind and become adept at controlling/navigating them. This is totally anecdotal and based only on experiences I've had though. It's hard to make blanket statements about the nature of psychedelics.