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BackgroundThe concurrent use of cigarettes with other tobacco products, such as smokeless tobacco (SLT), is increasingly common. Extant work with cigarette smokers who also use SLT is based heavily on retrospective reports and between-group comparisons. The purpose of this study was to assess prospectively the patterns of dual users’ product use and nicotine exposure on days when cigarettes were smoked exclusively (single use) versus concurrently with SLT (dual use).DesignForty-six dual cigarette-SLT users recorded their product use in real time via ecological momentary assessment for a 2-week longitudinal design. They responded to questions about situational factors (eg, location, mood) using this same diary, and collected saliva samples each night for later cotinine measurement. At the end of this 2-week period, users reported on their reasons for and beliefs about SLT use.ResultsCotinine levels were significantly higher on dual versus single use days (mean±SEM=374.48±41.08 ng/mL vs 300.17±28.13 ng/mL, respectively; p<0.01), and the number of cigarettes logged was higher on dual versus single use days (11.13±0.98 vs 9.13±1.11, respectively; p<0.01). Product use was distinguished by situational factors, with the strongest predictor being location of use. Moreover, the most common reason for initiating (56.52%) and continuing (67.39%) SLT use was to circumvent indoor smoking restrictions.ConclusionsResults support the idea of product supplementation rather than replacement among this convenience sample of dual users. For smokers whose primary motivation for SLT use involves situations where they would otherwise be tobacco free, the potential benefits of clean indoor air laws may be diminished.

Individuals with attention-deficit/hyperactivity disorder tend to make risker choices during probabilistic-discounting procedures. Thus, how common attention-deficit/hyperactivity disorder medications affect probabilistic discounting is of interest. In general, d-amphetamine increases risk-taking while atomoxetine has produced mixed effects in rats. Results from previous studies may result from genetic factors. Lewis and F344 rats have neurochemical differences that may be relevant to probabilistic discounting and how drugs affect such behavior. In this study, we evaluated dose-dependent effects of d-amphetamine and atomoxetine on probabilistic discounting of Lewis and F344. Male Lewis and F344 chose between one food pellet delivered 100% of the time and three food pellets delivered following decreasing probabilities of delivery (i.e. 100%, 66.7%, 33.3%, 16.5%, and 8.25%). Saline, d-amphetamine (0.1–1.8 mg/kg), and atomoxetine (0.1–7.8 mg/kg) were tested acutely. Lewis and F344 did not differ in choice at baseline. d-Amphetamine increased risky choice for both rat strains at low-to-moderate doses, although it did so at a lower dose (0.1 and 0.3 mg/kg) for F344 as compared to Lewis (0.3 mg/kg only). At high doses (1.0 and 1.8 mg/kg), d-amphetamine disrupted choice, increased frequencies of omitted trials, and reduced reinforcer sensitivity. Although atomoxetine increased frequencies of omitted trials at high doses (5.6 and 7.8 mg/kg), it had no effect on probabilistic discounting for either rat strain. Although Lewis and F344 differ in various types of impulsivity (i.e. motor, choice), with Lewis being the more impulsive of the two, the present results suggest that Lewis and F344 do not differ in risk-based decision-making. Effects of d-amphetamine on probabilistic discounting may be biology-dependent and differ from effects of atomoxetine.

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