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

吸烟是美国可预防死亡的主要原因之一，每年与健康相关的经济成本超过1930亿美元。与其他形式的成瘾一样，奖励过程的损伤被认为是尼古丁依赖的重要标志。公共卫生运动和成瘾研究主要集中在重度吸烟者（每天吸烟超过10支）。每日轻度吸烟者（定义为每天吸1-5支香烟的人）受到的关注相对较少，尽管低水平吸烟对公共卫生产生了重大影响。近年来，轻度吸烟率急剧上升，特别是在新兴成年人（18-25岁的个人）中。轻度吸烟者表现出尼古丁依赖的许多临床相关症状（例如，尼古丁戒断，无法戒烟），但在 他们表现出这些症状的程度。除了尼古丁依赖性的变化外，成年初期的轻度吸烟在吸烟轨迹方面也有所不同。许多轻度吸烟者有可能发展为更高的吸烟率和更高的依赖性，而其他人则几乎没有依赖性，最终停止吸烟。目前，人们对轻吸烟者在成年初期的尼古丁依赖程度和吸烟轨迹的差异知之甚少。拟议的初步研究的目标是通过检验对非药物奖励的敏感性是轻度吸烟新兴成年人尼古丁依赖严重程度的重要标志这一总体假设来解决这一知识差距。针对这一人群，拟议的研究有两个具体目标：1）检查尼古丁依赖水平与奖励相关抑制控制之间的关系; 2）检查尼古丁依赖水平与戒烟能力之间的关系，以获得非药物激励。如果成功的话，未来的研究将使用脑成像和纵向方法的组合来扩展这个试点项目，以表征对非药物奖励敏感性的个体差异的神经机制，并检查随着吸烟模式随着时间的推移在轻度吸烟新兴成年人（即，随着他们逐渐变得更重或更轻的吸烟）。这项试点研究的结果及其用于支持的后续研究计划将对制定旨在识别可能表现出吸烟和成瘾严重程度升级的轻度吸烟者的策略产生重要影响。此外，研究结果将为干预措施提供信息，这些干预措施的目标是在这个未充分研究的人群中维持吸烟行为的动机机制。考虑到与吸烟相关的巨大成本，包括在相对较低的水平上，即使通过这种技术在吸烟预防和治疗方面取得适度的改善，也会对公共卫生产生重大效益。

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.