My first experience with opiates was like a hug from God. No pain, no fear, no sadness. Just the feeling that I was finally ok and that I had found what was missing in my life and that everything would be all right.
My last experience with opiates was like a dutch rub from my weird uncle Bim. Unpleasant, somewhat nauseating, somewhat painful, but at least it was familiar, and anyway, he’s family.
Just because one can access the brain directly thru the nose doesn’t mean that one should. The olfactory nerve functions by taking up a few molecules at a time, to identify chemicals in the environment. Using it to get neuroactive compounds into the brain quickly is just as silly as using your nose to drink liquids. The nose can pass fluids into the stomach, bypassing the mouth. But the cost is high.