I missed
this in April's copy of Scientific American, but chanced upon it today - I normally read and reread SciAm and New Scientist but I've been busy.
Here is the article from the Journal of Family Practice that inspired the article.
Anyway, it is a very interesting study indeed.
To summarize for those who don't have the inclination to read such a large article:
1. Symptoms of withdrawal can occur within the first weeks of smoking - leading scientists to devise new models of how it affects the brain - previously it has been believed that the initial use of cigarettes was a psychological one, with physical addiction kicking in later.
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2. The new theory says the brain quickly adapts to nicotine exposure, and when it is no longer present withdrawal symptoms occur since the adaptation is still in place.
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3. The period of time between nicotine exposure and symptoms of withdrawal depends on the frequency of nicotine exposure. Therefore, self-described "social-smokers" who smoke only a few cigarettes a week are able to do so because the latency-withdrawal period is larger than daily smokers.
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4. Nicotine withdrawal does occur in those who smoke fewer than 5 cigarettes per day - contrary to previous assumptions that dictated that those who smoke less than the required amount to keep a constant level of blood-nicotine levels could not be addicted.
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5. This leads to an interesting paradox in which smokers without nicotine in their system (ie, after 12 hours) may not suffer any withdrawal symptoms until after that point. The traditional model assumes that withdrawal is dictated only by the lack of nicotine in the system.
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6. In this new model, a novice smoker is likely to smoke again at some point regardless of the amount already smoked. If he does not, he will likely experience withdrawal and the urge to smoke. Over time, the latency to withdrawal period will shorten as he preemptively smokes to avoid symptoms. The circle is thus completed and addiction sets in.
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7. The brain is permanently restructured by nicotine, dependent on the intake and duration of usage. It never returns to its pre-exposed state, although those who do quit end up with a brain dissimilar to both smokers and those who have never smoked.[/*:m:373h5twz]
I have to say that this mirrors my early experience of smoking far better than other studies on nicotine addiction that I have read over the years.
Another intersting point raised in the Journal article, is that of those who experience the FIRE response (First Inhalation Relaxation Experience - experienced by roughly a quarter of young people) from a cigarette, 91% subsequently lost autonomy over their control of smoking. Pretty remarkable, huh?