[XorNot]

That provides precisely no evidence that consciousness is somehow related to events on the quantum level. We know why drugs have the effects they do - because the brain has receptors specifically calibrated to accept or reject molecular inputs. But those inputs are chemical, not quantum - they are not indeterminate, they are lynchpins in chains of chemical reactions.

You omit that if you give a much larger dose of the same thing you'd kill a person, and a smaller dose might fall below any threshold of activity at all.

And for that matter, a microgram is a huge quantity of matter.