Nicotine preference in smokers as a function of smoking abstinence.

Overnight smoking abstinence increases desire to smoke and intensity of smoking behavior in smokers, but it is not completely clear that this reflects an increase in reinforcement from the psychoactive effects of nicotine per se. We examined choice of nicotine vs. placebo via nasal spray (Study 1) and nicotine vs. nonnicotine cigarette puffs (Study 2) in separate groups of smokers during each of two sessions, following overnight abstinence vs. no abstinence. In each study, subjects followed a forced choice procedure in which they were instructed to self-administer six sprays/puffs from between the two nasal sprays/cigarettes every 15 min for 2 h following initial exposure to each. In Study 1, choice of nicotine spray (1.5 micrograms/kg per spray) increased significantly following abstinence vs. no abstinence (47 +/- 6% vs. 34 +/- 5%, respectively, p < 0.05). This shift in choice was more pronounced in the subset of smokers (choosers, n = 9 out of 24) who selected nicotine on more than 50% of choices on the abstinent day. Choosers exhibited greater responses to initial nicotine exposure on positive (e.g., pleasant, vigor) but not aversive (e.g., jittery, uneasy) subjective measures, suggesting that greater positive reinforcement from nicotine per se predicted subsequent choice. In Study 2, abstinence similarly increased choice of nicotine vs. nonnicotine cigarette puffs (82 +/- 6% vs. 64 +/- 8%, p < 0.05), although nearly all subjects (12 of 13) preferred the nicotine cigarette following abstinence. These results indicate that choice of nicotine per se, isolated from tobacco smoke, increases significantly after overnight tobacco abstinence.