Theoretical, and controversial, but some studies say meditation is kind of similar in its effects. Helps bring the conscious mind in sync with the subconscious. Again, that’s the theory. Religious ecstasy does this as well, which also can be “practiced.” Buddhists do this daily. Born again Christians say it happens the moment they accept Jesus as their savior. But if they’re not mystic adepts, it never happens to them again.
(Have always been fascinated by mysticism. Included much about it in a coupla of my unpublished novels. Well, all of my novels are unpublished!)
Psychedelics would be another route to the same thing, though far more intense and direct. A short cut of sorts? Merging the conscious and unconscious minds is likely pretty damn healthy, but it also likely needs guidance . . . Too bad Carlos Castaneda is no longer alive. At least not on this astral plane.
One of my favorite poets and writers in general is Henri Michaux, the Belgian genius. He experimented with mescaline and other drugs and wrote about that. Painted under the influence too.