The Effect Of Abstinence From Smoking On Stress Reactivity

Subjective stress is a well-documented predictor of early smoking relapse, yet our understanding of stress and tobacco use is limited by the reliability of current available measures of stress. Functional magnetic reasoning imaging (fMRI) could provide a much-needed objective measure of stress reactivity. The goal of this dissertation is to contribute to the understanding of abstinence-induced changes in stress reactivity by examining neural, neuroendocrine (cortisol), and subjective measures of stress response during abstinence. In addition, this study investigated the influence of individual variation in nicotine metabolism rates on these measures of stress reactivity. Seventy-five treatment-seeking smokers underwent blood oxygen level dependent (BOLD) fMRI during the Montreal Imaging Stress Task (MIST) on two occasions: once during smoking satiety and once following biochemically confirmed 24-hour abstinence (order counter-balanced). The primary outcome measure was brain response during stress (vs. control) blocks of the MIST. Neural stress reactivity during abstinence (vs. satiety) was associated with significantly increased activation in the left inferior frontal gyrus (IFG), a brain region previously associated with inhibitory control. Greater abstinence-induced change in brain response to stress was associated with greater abstinence-induced change in subjective stress. However, there was no association with abstinence-induced change in cortisol response. In addition, higher rates of nicotine metabolism were associated with increased abstinence-induced change in self-reported stress, but not with brain or cortisol response. This study provides novel evidence that the brain response to stress is altered during the first 24 hours of a quit attempt compared to smoking satiety. These results underscore the importance of stress response during abstinence, and suggest that neuroimaging may provide a useful biomarker of stress response during the early smoking cessation, a period when smokers are most vulnerable to relapse

Different Lines of Rats Selectively-Bred for High Alcohol-Drinking Demonstrate Disparate Preferences for Nicotine Self-administration

Background. Alcohol and nicotine are commonly co-abused. The search for a common core of neural, behavioral, and genetic factors underlying addiction has been the goal of addiction research. Purpose. Genetic predisposition to high alcohol intake has been studied in rats by selectively breeding rats that have high preference for alcohol. The current experiments were conducted to determine if the level of intravenous nicotine administration for the various lines of alcohol-preferring rats differs from that for nonalcohol-preferring controls. Study design. Adult alcohol-naïve selectively-bred alcohol-preferring male rats from four lines (P, AA, HAD-1, sP) and their control nonalcohol-preferring rats (NP, ANA, LAD-1, sNP) were trained and given access to self-administer nicotine (0.03 mg/kg/infusion). Results. The results show that the P rats self-administered significantly more nicotine than NP rats. In contrast, there were no significant differences in nicotine self-administration between the sP and sNP or the AA and ANA rats. Unexpectedly, high alcohol-drinking HAD-1 rats self-administered significantly less nicotine than low alcohol-drinking LAD-1 rats. Conclusion. This suggests that some genetic factors that underlie high-alcohol intake have more general effects in promoting high nicotine intake tendencies, while other genetic factors are more specific to only heavy drinking

Brain Marker Links Stress and Nicotine Abstinence

Background: Subjective stress is a well-documented predictor of early smoking relapse, yet our understanding of stress and tobacco use is limited by reliance on self-reported measures of stress. We utilized a validated functional neuroimaging paradigm to examine whether stress exposure during early abstinence alters objective measures of brain function.Methods: 75 participants underwent blood oxygen level dependent (BOLD) functional magnetic resonance imaging (FMRI) during the Montreal Imaging Stress Task (MIST) on two occasions: once during smoking satiety and once following biochemically confirmed 24-hour abstinence (order counter-balanced). The primary outcome measure was brain response during stress (vs. control) blocks of the MIST, assessed using whole-brain analysis corrected for multiple comparisons using clusters determined by Z≥3.1.Results: Abstinence (vs. satiety) was associated with significantly increased activation in the left inferior frontal gyrus, a brain region associated with inhibitory control. Abstinence-induced change in brain response to stress was positively associated with change in self-reported stress.Conclusions: This study provides objective evidence that the brain response to stress is altered during the first 24 hours of a quit attempt compared to smoking satiety.Implications: These results point to the potential value of inoculating smokers with stress management training prior to a quit attempt.publishe