I know some folks in the HN audience will not like this example, but Elon Musk is one.
An older cannonical example is Timothy Leary.
No names are coming to mind, but I feel like there have been plenty of psychedelic informed cults, with cult leader narcissists who continue to abuse people despite experiencing psychedelics.
It may open some doors and cause you to consider more angles, and for many people it helps them with empathy and connectedness, but in another sense it's amplifying what you've already got. A "bad" input can get amplified too.
Manson would dose himself and his followers to, IMO, lower inhibitions and make them more receptive to his ideas.
Isn't he also a ketamine junkie? Ketamine is a dissociative anesthetic, although some call it psychedelic, it's not exactly the same thing.
In addition to other, unrelated drugs.