Smoking and Tobacco Control Monograph No. 7 
or more soon return to smoking (U.S. Department of Health and 
Human Services, 1988). There are two lessons here. First, incentives and 
motivation are important factors in the treatment of nicotine and other 
drug dependencies. Second, incentives and motivation have limitations; 
even the threat of death is not sufficient for half these smokers to stop 
smoking. 
This is a tenacious addiction in which, despite so many people wanting 
and trying to quit, fewer than 1 in 10 has a 1-year success, and this means 
that only 2 to 3 percent of smokers stop smoking each year (Fiore, 1992). 
Indeed, as Kozlowski and colleagues (1989) show, more than half of heroin 
and cocaine users and alcoholics rate smoking cigarettes as harder to give 
up than these other drugs. Thus, there are strong biological pressures in 
nicotine-dependent humans that do not exist in machines to sustain 
addictive levels of nicotine intake. 
Clinical As with dependence on other drugs, cigarette smoking tends to be a 
Characteristics progressive, chronic, relapsing disorder (U.S. Department of Health 
and Human Services, 1988). The most notable distinction between cigarette 
smoking and other drug dependencies is that a much higher percentage of 
people who start smoking escalate and graduate to dependent levels than 
with other addictive drugs. About 1 in 10 smokers in this country is a low- 
level smoker, termed a "chipper," who smokes 5 or fewer cigarettes per day 
(U.S. Department of Health and Human Services, 1988); most of the rest 
show evidence of dependence. This is in contrast to alcohol use, where 
10 to 15 percent of alcohol drinkers are problem drinkers; the rest generally 
drink in moderation and at times of their own choosing (U.S. Department 
of Health and Human Services, 1988). 
People do not start smoking a pack of cigarettes per day. They likely 
would become ill at that level of nicotine intake. Rather, they start out 
with low levels. Over months and years, most people progress to higher 
and higher nicotine intake. They become tolerant; that is, nicotine loses 
effectiveness with its continued presence in the body, and it is necessary to 
increase the dose to maintain its effectiveness after repeated administrations. 
Eventually, smokers do more than simply tolerate high nicotine doses; they 
need continued nicotine to feel normal and function satisfactorily. At this 
point, smokers may go to great lengths to continue smoking and sustain 
their nicotine intake within upper and lower boundaries so that their intake ! 
does not fall low enough that they experience withdrawal symptoms or ! 
high enough to produce adverse effects (Kozlowski, 1989). 
An important aspect of the chronic nature of tobacco dependence is 
related to daily patterns of nicotine blood levels. When smokers wake up 
in the morning, some residual nicotine remains in their blood from smoking 
on the previous day. Blood concentrations rise as they smoke until, by 
midafternoon, most smokers' intake equals metabolism and excretion, and 
nicotine level stabilizes, l.evels fall rapidly overnight, and the cycle resumes 
the next day. I'hus, blood concentrations never reach zero unless the person 
quits smoking for more than a few days. Moreover, cotinine, an active 
1 14 
