Active clinical trials for "Tobacco Use Disorder"

The purpose of this study is to investigate the effects of nicotine metabolism on occupancy of [11C]-(+)-PHNO to DA 2/3 receptors in different brain areas during periods of abstinence and smoking during an abstinence. This will be a Positron Emission Tomography (PET) study and the radiotracer [11C]-(+)-PHNO (11C]-( + )-4-propyl- 3,4,4a,5,6,10b-hexahydro-2H-naphtho[1,2-b][1,4]oxazin-9-ol) will be used.

Nicotine 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.

Smokers 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.

A 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.

The 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.

This study examines the potential effect of reducing nicotine content or menthol or both in men. It will also examine whether there are gender differences in manipulating tobacco flavors and nicotine concentrations in cigarettes on smoking behavior.

The 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.

In 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.

This study will examine the short-term cardiovascular (CV) effects of e-cigarette device power in a randomized, crossover clinical and behavioral pharmacology study of experienced adult e-cigarette users (N=21). The specific aim is to determine the impact of e-cigarette power on nicotine pharmacology, systemic exposure to toxic volatile organic compounds (VOCs), and short-term cardiovascular effects.

To examine the acute reinforcing effects of menthol, a fruit flavor (green apple) or a fruit flavor plus menthol, alone or in combination with nicotine in smokers. Flavors will be administered by inhalation via electronic cigarettes (e-cigarettes) and nicotine will be administered intravenously. The reinforcing drug effects will be measured with the drug effects questionnaire (DEQ).