Very good find, and well commented!
Unfortunately this study also supports age-old concepts like replacement of nicotine with bupropion (which doesn't work in some people and in others might be dangerous) and how "dangerous" continued use of nicotine is, giving more cannon-fodder to current politico-medical beliefs.
It also begs the question: how long does it take for serotonin to recover to pre-nicotine levels? I'm betting that in many cases it simply never does.
I've had so many people (non-smokers of course) tell me that if i can just stick it out through the withdrawal i'll feel better than ever. I sure tried to stick it out, until i had to go to the hospital. Then I had several medical professionals; doctors, nurses, emt's, etc.;
tell me that i should not quit smoking because the "withdrawal" can last a very long time (how long they did not specify) and it is too dangerous for me to quit.
It's really something when doctors tell you
not to quit smoking.
My point is, at the present time these disruptions in serotonin by nicotine abstinence are assumed by many to be temporary and, therefore, cessation is assumed to simply create a manageable period of adjustment. I would love to see similar studies on if and when the brain actually recovers. If we can prove that the brain never recovers for some people, then we would have a strong scientific basis for long-term use of high doses of nicotine.