This is such an awesome thread, I can�t believe I haven�t read it until now. {bad me}
According to the medical community, the nicotine is out of your system within 72 hours. At that point, presumably, the physical withdrawal symptoms will stop and most do. However, there is much more to craves than just physical withdrawal. When we smoked the nicotine over-stimulated our reward centers. As a result, the brain shut down some of these centers in an attempt to return to normal, where normal was our pre-smoking state. Over the years these unused reward centers atrophied and went away, literally. A similar process occurs for any constant stimulation, i.e. a wedding band.
When we quit smoking, we lost the nicotine�s stimulation of the reward centers. That plunged us into a �reward deficit� condition and this is the source of the depression, sadness, crying, etc. Over time, medical research says typically 12 � 18 months, our brains will recover. This is done by literally re-growing the nerve pathways in the reward centers that atrophied under the presence of nicotine. In the beginnings of our life, we had 12 � 18 years to develop the pathways nicotine destroyed. For them to recover in 12 � 18 months is, IMO, nothing short of miraculous. It is in this recovery that rewards play such an important role. Just as physical exercise helps atrophied muscles rebuild and recover, so do rewards help the brain�s reward centers rebuild and recover. Think of rewards as free-weights for the brain. They aren�t just to make us feel good about ourselves, they are literally rehabilitation.
Concerning the time-related craves. I�ve seen many people join this board saying they had previously lost a quit at 30 days, 100 days, 3 months, 4 months, 6 months, and 10 months. Far more than just coincidence could explain. While we do warn of them, and there may be some self-fulfilling prophecy effect in play here, these events are not limited to the SSC. The reason I mention them to newbies is in the spirit of forewarned is forearmed. My �100-day� event (between days 85 � 89, actually) was the worst of my entire quit. The craves of just one of the three nights exceeded the total of all the others combined, both before and after. The misery was worse than when I brok