About 25% of adults continue to smoke, about 70% of them want to quit. In one study, of the women smokers who said they wanted to stop smoking, 80% of them were unable to. Nicotine is a psychoactive drug, and some researchers feel it is as addictive as heroin; in fact, nicotine has actions similar to cocaine and heroin in the same area of the brain.

Depending on the amount taken in, nicotine can act as either a stimulant or a sedative. Most smokers have a special fondness for the first cigarette of the day because of the way brain cells respond to the day's first nicotine rush. Rat studies show that nicotine increases the activity of dopamine, a chemical in the brain that elicits pleasurable sensations -- a feeling similar to achieving a reward. The first nicotine intake of the day is particularly effective in enhancing the activity of dopamine-sensitive neurons. During the day, however, the nerve cells become desensitized to nicotine; smoking becomes less pleasurable and smokers may be likely to increase their intake to get their "reward". A smoker develops tolerance to these effects very quickly and requires increasingly higher levels of nicotine.

Withdrawal is a difficult process. Even after years of nonsmoking, about 20% of ex-smokers still have occasional cravings for cigarettes. A study in 1986 reported that 68% of all smokers wanted to quit, and in that year a third of them tried seriously, but only 6% of all smokers succeeded. People who keep trying, however, have a 50% chance of finally quitting, and in any case the attempts to quit are never a waste of time, since the amount of smoking is reduced during these periods.

Researchers have been trying to discover those conditions or sets of behaviors that can help predict why so many people fail to quit. From one study to the next, however, no consistent factors have emerged; these include gender, number of cigarettes smoked, levels of nicotine in the blood, length of time smoked, or the intensity or severity of withdrawal. A 1994 study, however, did find one consistent predictor for failure to quit: almost anyone who cheated during the first two weeks of withdrawal, even if they were wearing the patch, was smoking again in six months. On the other hand, nearly half of the people who didn't cheat during the first two weeks were still not smoking after sixth months.

A recent study indicates that smokers who quit and start again may damage their lungs even more severely than people who have not yet made an attempt to quit. Some experts suggest that those who relapse may have been at high risk for poor lung function in the first place or that those who start smoking again are more strongly addicted than other smokers and may inhale more deeply and hold the smoke in their lungs longer. The message here is not that quitting smoking is more dangerous than not quitting; the emphasis is on not starting again.

Copyright * 1998 Nidus Information Services, Inc. Well-Connected Report: Smoking. September 1998. (Online)