Effects of smoking on mental performance and vegetative functions in high and low CO absorbing smokers.

The present study investigated effects of smoking on mental performance and concomitant psychophysiological reactions in smokers differing in the strength of their habit. Toward this goal performance in two 30-min rapid information processing (RIP) trials separated by a 10-min smoking period was compared among preselected high and low CO absorbing smokers, nonsmokers, and smokers not allowed to smoke (n = 12 per group). Heart rate, finger pulse amplitude, and respiratory frequency were continuously recorded throughout the experimental sessions in order to assess physiological arousal and to estimate nicotine absorption through smoking. The RIP test consisted in the detection (button pressing) of triads of odd or even digits out of a series of single digits presented in a subject-paced manner on a screen in a pseudorandom sequence. Performance significantly increased from the first to the second trial in all groups, and this increase tended to be greater in both the high and low CO absorbers than in the two control groups. The similar development of RIP in the low and high CO absorbers is contrasted by differential vegetative responses to smoking. Smoking increased heart rate and respiratory frequency and produced peripheral vasoconstriction in the high CO absorbers only, suggesting the absorption of nicotine, whereas no nicotinic effects were noted in the low CO absorbers. The results are discussed in the light of the observed dissociation between psychological and physiological effects of smoking in the two groups of smokers, and the possibly differential role of nicotine for smoking motivation in the two groups.