Native Americans have been using similar methods for centuries to reach the inner self and they are not nor were not “tuning in and dropping out”.
It is all in my opinion a matter of having others nearby to guide you and provide grounding and assistance in the journey. The state of mind of the individual before ingestion is also key, it clears away the issues present in the concious state and promotes connection with the other levels of the mind, and to a higher vision of self.
I know some of you will come back at this and I understand your perceptions in this area. Human kind has sought an altered state since the beginning of time, whether by alcohol, ingestion of plants or whatever means. It is the nature of the beast as they say.
My understanding of the subject is that LSD actually turns on chemicals and other elements inherent in the human brain unlike other “drugs” that introduce new ones into our systems.
No matter by what means humans seek to find an altered reality, it has always been this way and always will.
The problem with human minds is, they're all tuned a bit differently, and they all contain unique and wildly varying contents. Two people could 'clear their minds' and embark upon an LSD trip with others nearby to 'guide' them, and one would have a wonderful experience, while the other had a bad trip.
I spent years experimenting with the stuff when I was very young, and know for a fact that the quality of the experience is entirely dependent upon what's already in the travelers' mind and personality. LSD can also turn on a person like a beloved pet who's contracted a case of rabies. That happened to me, and lots of others who formerly used.