Loss of acute nicotine tolerance and severity of cigarette withdrawal.

Twenty-one smokers underwent 24-h abstinence from cigarettes. Both prior to, and after, the abstinence period cardiovascular and subjective effects of smoking a cigarette were measured. Withdrawal symptoms found during abstinence were: irritability, depression, hunger, difficulty concentrating, restlessness and urges to smoke. In addition, the subjects reported feeling physically less well. Withdrawal discomfort was positively correlated with the strength of the subjective effects (e.g. dizziness, nausea) of smoking the post-abstinence cigarette after taking account of estimated nicotine boost from that cigarette. A similar, though only marginally significant association was found between withdrawal severity and heart rate boost from the post-abstinence cigarette. Our results suggest that the severity of withdrawal may be related to loss of acute tolerance to nicotine. It is not clear whether this is due to more rapid nicotine clearance, constitutional differences in sensitivity to nicotine in the absence of acute tolerance, or other factors. There was no evidence to support the view that higher chronic tolerance to nicotine's heart-rate effects was associated with more severe withdrawal. If anything, the reverse appeared to be the case.