Nicotine dependence, reward sensitivity, and lapse behavior in light smokers

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DESCRIPTION (provided by applicant): Cigarette smoking is one of the leading causes of preventable death in the United States, with health-related economic costs that exceed $193 billion per year. As with other forms of addiction, impairments in reward processing are thought to serve as important markers for nicotine dependence. Public health campaigns and addiction research have primarily focused on heavy smokers (those smoking >10 cigarettes per day). Daily light smokers (defined as those smoking 1-5 cigarettes per day) have received comparatively less attention despite the substantial public health impact of low-level cigarette use. Rates of light smoking have increased dramatically in recent years, particularly among emerging adults (individuals aged 18-25). Light smokers demonstrate many clinically relevant symptoms of nicotine dependence (e.g., nicotine withdrawal, inability to quit), but vary greatly in terms of the extent to which they exhibit these symptoms. In addition to variability in nicotine dependence, light smoking during emerging adulthood also varies in terms of smoking trajectory. Many light smokers are at risk of progressing to higher rates of smoking and increased dependence, whereas others experience little dependence and ultimately discontinue smoking. Currently, little is known about the widely varying levels of nicotine dependence and divergent smoking trajectories observed among light smokers during emerging adulthood. The goal of proposed pilot study is to address this knowledge gap by testing the overarching hypothesis that sensitivity to non-drug rewards serves as an important marker for nicotine dependence severity in light smoking emerging adults. Focusing on this population, the proposed research has two specific aims: 1) To examine the relationship between level of nicotine dependence and reward-contingent inhibitory control; and 2) To examine the relationship between level of nicotine dependence and the ability to refrain from smoking in order to obtain non-drug incentives. If successful, future research will extend this pilot project y using a combination of brain imaging and longitudinal methods to characterize the neural mechanisms underlying individual differences in the sensitivity to non-drug rewards and to examine changes in the behavioral and neural responsiveness to non-drug rewards that occur as smoking patterns evolve over time in light smoking emerging adults (i.e., as they progress to heavier or lighter smoking). Results from this pilot study and the subsequent program of research it is used to support will have important implications for developing strategies aimed at identifying light smokers who are likely to exhibit an escalation in cigarette use and addiction severity. In addition, findings will be informative for interventions that target the motivational mechanisms perpetuating smoking behavior in this understudied population. Given the enormous costs associated with cigarette use, including at relatively low levels, even a modest improvement in smoking prevention and treatment gained through such techniques would have significant benefits for public health.