> I would be tempted to think the fact drugs are rare and difficult to obtain the first times decrease the odds of somebody becoming an addict. Pure speculation but there is some logic still. Say one night I'm crazy, I'm not going to find cocaine right away become hey, tonight is the night. I understand that it's not a proof that it's effective. Just that it might be.

Your logic seems fine to me, but it's based on an assumption that it is hard for people to find drugs for the first time. You're probably not frequently presented with opportunities to do heroin, but you're also probably not the kind of person who would do heroin even if you had the opportunity. Drug dealers aren't going to approach you to sell you heroin because the risk/reward ratio is too high. The same is not true of teens and people in their 20s in poor neighborhoods.

> Doctors prescribe morphine, most likely when not using it is worse than using it, which doesn't mean the risk are low.

True.