Euphoriant effects of nicotine in smokers.

Two studies were conducted to replicate and extend previous demonstrations of smoking-induced, dose-related reports of euphoria, and to confirm this relationship using measures of plasma nicotine. In experiment 1, overnight-deprived subjects, in three different sessions, smoked ultralow-, high-nicotine, and usual-brand cigarettes. In experiment 2, ultralow-, medium-, and high-nicotine cigarettes were used, and plasma nicotine was measured. In both studies, subjects were asked to depress a button during euphoric sensations. Number of sensations for the ultralow-nicotine cigarette was significantly lower than for the high-nicotine cigarette in the first study, and than for both the medium- and high-nicotine conditions in the second; a significant linear trend was observed for number of sensations as a function of plasma nicotine level in the second study. For the high-nicotine cigarette, 19 of 22 subjects experienced at least one sensation (mean around three), starting around 2.5 min after lighting up. Together, these studies support the existence of a dose-response relationship for nicotine-induced euphoric sensations; suggest that they are more pronounced following overnight abstinence than following minimal deprivation, and in more dependent smokers; and characterize in detail the temporal features of these sensations.