Joseph Campbell said this quote

“ The LSD phenomenon, on the other hand, is—to me at least—more interesting. It is an intentionally achieved schizophrenia, with the expectation of a spontaneous remission—which, however, does not always follow. Yoga, too, is intentional schizophrenia: one breaks away from the world, plunging inward, and the ranges of vision experienced are in fact the same as those of a psychosis. But what, then, is the difference? What is the difference between a psychotic or LSD experience and a yogic, or a mystical? The plunges are all into the same deep inward sea; of that there can be no doubt. The symbolic figures encountered are in many instances identical (and I shall have something more to say about those in a moment). But there is an important difference. The difference—to put it sharply—is equivalent simply to that between a diver who can swim and one who cannot. The mystic, endowed with native talents for this sort of thing and following, stage by stage, the instruction of a master, enters the waters and finds he can swim; whereas the schizophrenic, unprepared, unguided, and ungifted, has fallen or has intentionally plunged, and is drowning. ”