You can rarely get enough nicotine into your body without drinking the stuff to bypass nic sickness into death. It can be done but you really have to work at it.
The same can be said to be true for alcohol; that is why fraternity rush parties and binge drinking are dangerous. The consequences of drinking too much usually result in an aversion, leading you your "U shape," which is what I tend to think is what you are talking about.
I don't think nicotine and the brain has been studied enough to make the kind of claims you do. As far as I know, there are actual nicotinic shaped receptors that sprout in the brain and the die off process is approximately 2 weeks which is why they say if you can cold turkey two weeks you are no longer "Technically" addicted (I think it may be the acetylcholine receptors that sort of "accept" nic and sprout but don't quote me on that, it's been a while) but the truth to the matter with minor alkaloids and smoking and etc, not to mention TAR being an anti-depressant in and of itself, forget it.
I don't demonize nicotine and I don't think it's particularly harmful as far as drugs go. Since the
tobacco companies lack transparency in what they put in cigarettes however, I do demonize THEM and THAT. It's unconscionable.
I don't know what is making people die off from smoking younger and seem to smoke more than their very elderly counterparts, I noticed my smoking took off at a certain point when
tobacco companies started increasing nicotine levels, so maybe dripster has SOMETING of a point-- less may be more where nic is concerned, I don't really know enough to like, really know that much. I will say that was my last tapering quit, and I did it on Nat Shermans so there were no additives and I was like 21 or something, and I managed for a while. Once I was under 6 a day it got a lot easier but I had to work kind of hard, and I didn't have much else happening,
Once I went back forget it.
Also, it could have been other additives we just don't know. But I would also like a source.
No plans to smoke me into an early grave quite yet, LOL.
Anna