I did hear that drugs could bring us to higher states of consciousness but most of the time, we are not prepared and can invite unnecessary attention from denizens of other realms. Therefore, it would not be good especially if they are malevolent spirits wishing to harm because they themselves are angry and tormented. I think that the best gateway to Buddhism is always through our own practice. Our Lamas and Gurus already had given us plenty of meditational tools in which we can work with to develop inner qualities. On top of that, the drug-state in which LSD and other drugs induce does not allow us any control whatsoever and instead of gaining some sort of mastery over our mind like other Buddhist practice, drug use only lessen our control and in fact, make us addicts to the drug. That's not a Buddhist practice.
True enough, that would not be buddhist practice. Ive heard something about the Bon religion but don't have first hand knowledge.
My experience is they are two different developmental stages. Meditation practice requires total focus, dedication, total freedom from all substances, top notch physiological "full power" from great health, the best possible sleep quality, life organized around the practice without distraction to marshall every inner resource you can muster. It does require that. Thus the precepts. Psychedelics and other things can help to remove obstacles.
Few westerners, since we are so saturated with mental agitation and instability we live with from day one, are capable of deeper meditative states without some way to rid ourselves of those chronic obstacles, preliminary practices western style you might say. My observation is westeners can and do sit on that cushion until blue in the face and go nowhere, at all, even with truly qualified instruction and guidance, which by itself is also not at all common. In my experience great training is rare. Even native Tibetans do not understand from experiecne the unique obstacles faced by westerners, ie virulent mental instability, and solutions to those problems. The meditative practices were designed for people in a totally different epoch and culture.
LSD like substances and other methods (holotropic breathwork, psychotherapy, etc) can assist with that problem, helping to at times rapidly, clear such obstacles. I've had considerable experience with both. I know a psychiatrist and former researcher with experience guiding about 5000 people in LSD sessions, some of whom were seriously mentally ill to begin with who became well, who never once saw such negative reaction when the "tripper" was appropriately supported. In fact poorly supervised meditation practice can induce such mental illness too in some people. It's not really so cut and dried: meditation = always good, drugs = always bad.
Shamatha practice is taught to Tibetan monks also but has nothing to do with the religion. It is mental training strait up. If you can manage it, Shamatha takes you directly into Samadhi, that total quietude and focussed mind. Quite amazing.
I spent much of my adult life quieting down these very western style mental states which keep us agitatied and unstable, ie that virulent "monkey mind" that will not be still. Then the first weekend I got top notch (there is a big distinction vs poor quality) meditation training I went into Samadhi immediately. Two years later it was 24/7 and included vipassana and substrate and permanent release from most mental afflictions.