Smoking and Tobacco Control Monograph No. 7 
animals (Corrigall, 1991; Henningfield and Goldberg, 1983; Pomerleau, 1992; ; 
U.S. Department of Health and Human Services, 1988) and the negative 
reinforcement of withdrawal symptoms that also fuel the compulsion to 
smoke (Hughes and Hatsukami, 1992; Pomerleau and Pomerleau, 1984). i 
Nicotine also produces increased expression of brain nicotinic receptors in 
humans and animals (U.S. Department of Health and Human Services, 1988). | 
Taken together, these physiologic effects confirm that nicotine exposure alters ■ 
the structure and function of the nervous system and leads to modification of ( 
behavior. Thus, there are physiological factors that drive smokers to sustain 
continued nicotine intake across changing delivery systems. 
. 
Smokers may report that they feel impaired and distracted after only 
a few hours of abstinence, and their performance on various cognitive and 
psychomotor tasks can decline within approximately 4 hours (Heishman et 
al., 1994). Symptoms are rapidly reversed with resumed smoking or nicotine 
replacement, thus providing a potentially powerful source of reinforcement i 
for continued smoking. The degree of reversal is generally proportional to j 
the percentage of plasma nicotine that is replaced (Pickworth et al., 1989; i 
U.S. Department of Health and Human Services, 1988). ■) 
Data from a performance study indicated that when patients abstained 
from cigarettes and used placebo gum, they made more errors and took ^ 
longer to complete a task than during their smoking baseline. When they j 
were given 2 mg gum, their performance returned to baseline. With 4 mg j 
gum, they did not do significantly better than at baseline, but 4 mg appeared j 
to produce somewhat more reliable clinical effects than 2 mg (Snyder and 1 
Henningfield, 1989). jj 
The same pattern of effects occurs with theta power, a measure of brain I 
function (Pickworth et al., 1989). This nicotine-withdrawal-induced deficit j 
can be completely reversed with nicotine replacement. When other ! 
volunteers resumed smoking, electrocortical potentials recovered quickly ! 
in all volunteers. Interestingly, these people did not like the gum, and they i{; 
were not trying to quit smoking. The lesson is that nicotine replacement |l' 
can maintain physiological function and cognitive performance. The j|:' 
conclusion relating to performance is not that nicotine makes the user 
perform better, faster, or more intelligently but that nicotine deprivation 
results in impairments that are quickly and dose-dependently reversed by || 
nicotine readministration (Heishman et al., 1994). ,| 
I'he nicotine-withdrawal-induced decline in performance has practical | 
ramifications in policy decisions. Currently, the Federal Aviation | 
Administration is examining its policies on smoking by pilots in the ft 
flight decks of commercial airlines. Because of the time course of nicotine \] 
withdrawal, if smoking were eliminated in the flight deck, acutely deprived | 
pilots might suffer withdrawal-induced performance declines on flights I 
longer than approximately 4 hours. Thus, the nicotine withdrawal syndromej ! 
poses a potential safety hazard if it is not rationally addressed by appropriate , 1 
strategies to detoxify pilots safely and treat their withdrawal symptoms with ^ i 
nicotine replacement medications. , 
i' 1= 
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