The Role of Nicotine and Non-Nicotine Alkaloids in E-Cigarette Use and Dependence
Nicotine DependenceThe advent of electronic cigarette (e-cigarette) technologies represents one of the most significant developments in the last several decades, and provides a novel and promising strategy for substantially reducing the morbidity and mortality associated with smoking. However, serious concerns have been raised regarding the possibility that e-cigarettes will sustain a dependency on nicotine and that they may lead to continued use of conventional cigarettes known to be extremely harmful to health. Cigarette addiction critically involves a dependence on nicotine, but it is likely that other tobacco constituents contribute to dependence as well. Recent evidence suggests that non-nicotine tobacco alkaloids, or NNTAs (including anabasine, anatabine, nornicotine, and myosmine) may play a role in tobacco dependence. These alkaloids have been shown to augment the reinforcing effects of nicotine in animal models and to affect cravings in human smokers. E-cigarettes contain variable quantities of nicotine and NNTAs, but there is virtually no information available concerning the role of e-cigarette nicotine or NNTA content in influencing the concurrent use of cigarettes and e-cigarettes, when smokers attempt to switch from conventional combustible cigarettes to e-cigarettes. Additionally, it is not known whether the presence of nicotine and NNTAs in e- cigarettes may sustain dependence, making it difficult to relinquish these products. The proposed project will assess the acceptability, extent of switching behavior, and degree of dependence maintained when smokers are provided with e-cigarettes containing nicotine and NNTAs.
Flavors and E-cigarette Effects in Adolescent Smokers- STUDY 1
Nicotine DependenceOther Tobacco ProductThis study is to examine if inhaled doses of menthol that produce low and high cooling effects change the appeal of e-cigarettes containing low and high doses of nicotine in adolescent smokers. The hypothesis is that the combination of nicotine and menthol, when compared with menthol or nicotine alone, will result in greater increase in liking of an e-cigarette and greater reduction in nicotine withdrawal.
Project 2, Study 2: Extended Exposure to Low Nicotine Content Cigarettes in Opioid Abusers
Tobacco Use DisorderThis study will examine extended exposure to cigarettes varying in nicotine content among adults with opioid use disorder. Those with opioid use disorder are at increased risk for smoking, nicotine dependence, and using high nicotine yield cigarettes and are also at significantly increased risk for smoking-related adverse health consequences, including site specific cancers, heart disease, and premature death. Studies testing an innovative regulatory strategy of reducing the nicotine content of cigarettes to a non-addictive level have shown promising beneficial effects (decreased smoking rate, reduced toxicant exposure, and increased cessation) in the general population of smokers. However, these studies have uniformly excluded vulnerable populations like those with opioid use disorder who may respond differently considering their greater vulnerability to smoking and nicotine dependence. Thus, little is known scientifically about how this highly vulnerable subgroup of smokers might respond to a nicotine reduction policy. This project is designed to address that substantial knowledge gap. This same study was also conducted in two additional vulnerable populations under a similar protocol.
Novel Medication as a Potential Smoking Cessation Aid
Tobacco Use DisorderThe purpose of this study is to provide preliminary information assessing if levomilnacipran may be effective at increasing smoking cessation rates.
Test-retest Reproducibility of [11C]PHNO PET Using the Constant Infusion Paradigm
Nicotine DependenceHealthyA research study designed to examine amphetamine-induced dopamine release using the PET imaging agent [11C]PHNO in tobacco smokers while currently smoking and during acute withdrawal and in nonsmokers. Twenty healthy men and women tobacco smokers and twenty healthy nonsmokers will be recruited. Each subject will participate in 1 MRI and up to 2 [11C]PHNO PET scans. On the study day subjects will participate in two [11C]PHNO scans (ideally, the two PET scans will be carried out in the same day). Three hours before the second PET scan, amphetamine (0.5 mg/kg, PO) will be administered. In smokers, the scan will occur at 10-21 days of smoking abstinence.
Association of Functional COMT Val108/Met Polymorphism With Smoking Cessation in Nicotine Replacement...
Nicotine DependenceNicotine replacement treatment (NRT) can be efficacious for smoking cessation, but used by only a minority of smokers in China. Pharmacogenetic matching may improve treatment outcomes for NRT in subgroups of smokers. The investigators evaluated the efficacy and safety of sublingual nicotine tablets (SNT) for smoking cessation and the association of catechol-O-methyltransferase (COMT) genotype with efficacy in this smoking cessation trial among Chinese smokers.
Very Low Nicotine Cigarettes in Smokers With Schizophrenia
Tobacco DependenceSmokers with serious mental illness including those with schizophrenia and bipolar disorder infrequently attempt and attain sustained smoking abstinence and have a 25-year shorter lifespan due to smoking-related illness. This study will examine whether reducing the nicotine content of cigarettes to non-addicting levels is a viable method of reducing smoking in smokers with serious mental illness. Smokers will be randomized to one of two experimental conditions: 1) very low nicotine content (VLNC) cigarettes or 2) normal nicotine content (NNC) cigarettes. Participants will be assessed for patterns of tobacco use, biomarkers of exposure, subjective responses (e.g., satisfaction, craving, withdrawal symptoms), psychiatric symptoms, cognitive performance, smoking cue reactivity and smoking topography.
Acute and Chronic Nicotine Modulation of Reinforcement Learning
Nicotine AddictionThe purpose of this study is to use functional magnetic resonance imaging (fMRI) to investigate the acute and chronic effects of nicotine on motivational behavior and prediction error-related neural activation. Nonsmokers (n = 24) and smokers (n = 24) will undergo fMRI scans on two separate occasions while performing a decision-making task that will elicit prediction error signals in the mesocorticolimbic pathway of the brain. Nonsmokers will be scanned once following an acute dose of nicotine and once following placebo administration. Smokers will be scanned once following smoking as usual and once following 24-hours of smoking abstinence, in order to measure the effects of nicotine withdrawal. The study team hypothesizes that acute nicotine will increase the prediction error signal in nonsmokers compared to placebo, and that nicotine withdrawal will decrease the prediction error signal in smokers compared to the normal satiated condition. Furthermore, nonsmokers (during the placebo condition) will have greater prediction error activation than smokers (during the satiated condition). The results of this study will inform whether the initiation and maintenance of smoking behavior could be facilitated by the effects of nicotine on reinforcement learning.
Effect of a Non-Invasive Brain Stimulation Technique on Smoking Cessation Behaviors
Tobacco Use DisorderIn this pilot study, the feasibility of using tDCS (a non-invasive brain stimulation technique) while performing a task requiring cognitive flexibility will be examined in smokers and initial data will be collected regarding the effect of tDCS on smoking cessation behaviors. Smokers will be randomized to receive either active or sham tDCS daily for 5 days after which they will attempt to quit smoking. Smoking behavior after the attempted quit date will be assessed at four weekly visits.
Switching to Very Low Nicotine Content Cigarettes vs Reducing Cigarettes Per Day
Tobacco Use DisorderThe FDA recently gained the authority to regulate the nicotine content of cigarettes. Prior research suggests that smokers who switch to very low nicotine content (VLNC) cigarettes experience reduced addiction to nicotine and are more likely to quit smoking. Currently, the most common method for smokers to reduce their nicotine intake is to reduce their number of cigarettes per day (CPD). No research has compared reducing smokers' nicotine intake by switching to VLNC cigarettes vs by reducing CPD with regard to decreasing dependence or quitting; thus the investigators will examine the two strategies by randomizing smokers to 1) switch to VLNC cigarettes or 2) reduce CPD. In addition, all smokers will use the nicotine patch to help them reduce their nicotine intake.