Individual differences in responses to the first cigarette following overnight abstinence in regular smokers.

We utilized cluster analysis to identify individual differences in response to the initial effects of smoking following overnight abstinence among 183 regular smokers. Participants smoked three cigarettes (1 mg nicotine, spaced 30 min apart) in standardized fashion and completed questionnaires about their subjective responses to each cigarette. Heart rate was monitored throughout the procedure. Participants were grouped into two clusters based on their reported subjective effects and heart rate changes to the first cigarette. Clusters differed in terms of greater increases in heart rate, reports of dizziness, sweating, unpleasantness, nausea, and buzzing sensations in one group compared to the other group. The smokers showing increased responses developed greater acute tolerance to the effects of smoking subsequent cigarettes on subjective negative effects and heart rate, and experienced greater negative affect after quitting. These results are partially consistent with a nicotine sensitivity interpretation or a tolerance model of the effects of initial smoking.

Effects of dose and interdose interval on conditioned heart rate tolerance to smoking.

The effects of an environmental cue and smoking administration on heart rate (HR) responses to smoking were investigated in 2 studies. The 1st study was performed without smoking, to rule out the possibility that the cue manipulations alone could produce HR habituation. Thirty-six male nonsmokers were exposed to 6 trials of a changing or repeating cue (segments of a story on audiotape), followed by a paced-breathing period. HR habituation was not found. In the 2nd study, 40 male smokers smoked 4 puffs every 10 min (small-dose/long-interdose interval [IDI]) or 6 puffs every 5 min (large-dose/short-IDI) in 6 trials. The same repeating or changing cue preceded smoking. Only the repeating-cue, small-dose/long-IDI group developed HR tolerance. Modifying the cue on Trial 6 did not reverse tolerance. The results indicated that (a) tolerance to smoking appears to be subject to conditioning, (b) this effect depends on the dose and IDI, and (c) the observed tolerance is not likely to be a result of the effects of the cue alone. Nonassociative tolerance to smoking a high-dose/short-IDI did not occur in this study.