There is an experiment that I would like people who are not on narcotics but may have some laying around the house to try. Take one dose when you are not in physical pain or an unenviable state of mind. I think if you feel anything at all, it will be a touch of nausea and maybe a headache. And that will actually be it. It will be over in 1 to 10 hours depending on the drug. I don't even count fentanyl as a narcotic in the same sense as morphine -- it is a pharmacologically dirty (not a bad thing) general anaesthetic, so that doesn't count, and it has to be something you can swallow or dissolve under your tongue or comes as a nasal spray.
If you do feel really grand from it, maybe you can benefit from them. Narcotics were the anti-depressants and preferred anxiolytics in some cases until the late 1950s and are certainly easier for doctors and patients to manage and much less toxic than what has replaced them. Read the package insert about how to get off Prozac and things like that and tell me about physical dependence and habituation.
Not even something really potent like smack or hydromorphone will automatically make someone want to take it again under such circumstances. Not only are narcotics, like all drugs, inert substances with no ability to cogitate or move on their own and get into someone's bloodstream, I aver that narcotics are in fact much subtler drugs than things people take for fun like alcohol, C-Jam, pot, meth and some others, and people take narcotics because they need them to regulate their nervous system, viscera, and/or bones to feel better, to feel about as good as a lot of people do, and who is anyone to take that right from them? Managing one's nervous system is about as basic a human right as I can imagine.
The only people who do not fit that profile are big time poly-drugs users who quaff, pop, smoke, snort, shoot, rub into their belly, or stuff up their arsehole anything upon which they can lay their hands, and, when cutting down their chemical use, find themselves feeling sick because of the narcotics in their diet. And what exactly did they do to earn being treated like the government, a lot of the medical establishment, and others treat them?
Another case is people using narcotics to come down off meth, C-Jam, and things of that nature. That is in fact a medicinal use.