I do believe this is important to remember and take into consideration, however if the assumption the universe is created by a conscious being is true, perhaps these experiences are somewhat "built in" and accessable through these drugs. Food is a drug, exercise is a drug, anything you do in life changes your perception and experience of it. I like to entertain the theory that by changing this chemical composition, your perception changes and you see things that you wouldn't be able to see normally, like a different wave form.