IMO There is a much better case for: if you're not taking it in a spiritual setting you're doing it wrong.
Anecdotally I've had the bad experience and the life-changing transcendent experience, all self-directed.
In my experience. It's not good for partying, but it's very good for meditating and inquiring deep into the nature of your being, what reality is, what Love is and what God is.
I've had long periods in my life of being a hard-line rationalist atheist. And I've had direct encounters with God. If there is one thing I learned it's this: You can't take anything as a belief you have to validate it in your direct experience.
