Do smokers self-administer pure nicotine? A review of the evidence.
BACKGROUND
Nicotine is almost universally believed to be the primary agent motivating tobacco smoking and the main impediment to cessation. A principal argument in support of the presumed reinforcing properties of nicotine is that smokers self-administer pure nicotine. However, the evidence for nicotine self-administration in smokers has not been critically examined.


OBJECTIVE
To review and examine the empirical basis for the assertion that smokers self-administer pure nicotine.


METHODS
We reviewed all the studies we were able to locate that are cited as demonstrating self-administration of nicotine, isolated from tobacco, in normal smokers and non-smokers. These studies investigated self-administration of intravenous nicotine, nicotine gum and nicotine spray. Using the authors' own criteria, we examined whether these studies in fact demonstrate nicotine-self administration.


RESULTS
None of the studies we reviewed demonstrated nicotine self-administration in smokers. Both smokers and non-smokers failed to show preference for nicotine over placebo in any of these studies, including in a series of six reports of overnight abstinent smokers having access to nicotine nasal spray, a rapidly absorbed form of nicotine.


CONCLUSIONS
The common statement that smokers self-administer pure nicotine lacks empirical support. Smokers in fact do not administer pure nicotine in any of the forms studied to date, even when abstinent and presumably nicotine-deprived. This conclusion necessitates a critical re-examination of the nicotine addiction thesis.
Dar
Reuven
R
Department of Psychology, Tel Aviv University, 69978 Tel Aviv, Israel.ruvidar@freud.tau.ac.il
Frenk
Hanan
H
D000818:Animals; D004333:Drug Administration Routes; D006801:Humans; D009538:Nicotine / Q000008:administration & dosage*; D018722:Nicotinic Agonists / Q000008:administration & dosage*; D012054:Reinforcement, Psychology; D012646:Self Administration; D012907:Smoking / Q000523:psychology*
D018722:Nicotinic Agonists; D009538:Nicotine