Nicotine effects on affective response in depression-prone smokers.

RATIONALE: Comorbidity between cigarette smoking and depression is thought to arise because depression-prone smokers self-administer nicotine to improve mood. Yet little evidence supports this view, and nicotine's effect on positive affect deficiency in depression remains largely unstudied. OBJECTIVES: We hypothesized that (1) nicotine would dispel negative affect and enhance positive affect and (2) effects would be stronger for smokers vulnerable to depression, particularly during a depressed state. MATERIALS AND METHODS: Regular smokers (N = 165) were recruited from the community: 63 with no history of major depressive disorder (MDD), 61 with recurrent past but no current MDD, and 41 with both current and past MDD. During four sessions, participants smoked either a nicotinized (NIC+) or denicotinized (NIC-) cigarette double blind after experiencing a negative mood induction or while undergoing a positive mood induction. Positive and negative affects were measured at baseline and at two time points after smoking. RESULTS: Previously depressed smokers showed a heightened positive mood response to positive mood induction when smoking a nicotinized cigarette. Nicotine also increased the degree to which positive mood induction dispelled negative mood in depression-vulnerable smokers. Finally, nicotine worsened the negative affect response to negative mood induction for all groups. CONCLUSION: Self-administering nicotine appears to improve depression-prone smokers' emotional response to a pleasant stimulus.

Influence of nicotine on positive affect in anhedonic smokers.

RATIONALE: The possibility that individuals administer nicotine to self-regulate persistent negative affect has received interest as a possible explanation for the high prevalence of affectively vulnerable smokers. Relatively overlooked, however, is the possibility that smokers might also self-administer nicotine to elevate low positive affect. OBJECTIVES: This study examined whether nicotine administration augmented anhedonic smokers' positive affective response to a positive mood induction. MATERIALS AND METHODS: Fifty regular smokers (50% female) underwent two positive mood inductions during which they smoked either a nicotinized or denicotinized cigarette in counterbalanced order. Positive affect was assessed before and at two time points after smoking. RESULTS: Random effects regression showed a significant anhedonia by condition-by-time interaction [t(181)=-2.01, p = 0.04], supporting the hypothesis that anhedonia moderated nicotine's effect on changes in positive affect. Simple effect analyses showed a significant condition-by-time interaction among high anhedonic smokers [t(91)= 2.47, p = 0.01] but not among less anhedonic smokers [t(91)= 0.34, p = 0.73]. CONCLUSION: Smoking nicotine vs placebo heightened anhedonic smokers' ability to be induced into a positive mood, whereas nicotine had no effect on more hedonic smokers' positive mood.

Fluoxetine, smoking, and history of major depression: A randomized controlled trial.

The study was a randomized placebo-controlled trial testing whether fluoxetine selectively enhances cessation for smokers with a history of depression. Euthymic smokers with (H+, n = 109) or without (H-, n = 138) a history of major depression received 60 mg fluoxetine or placebo plus group behavioral quit-smoking treatment for 12 weeks. Fluoxetine initially enhanced cessation for H+ smokers (p = .02) but subsequently impaired cessation regardless of depressive history. Six months after quit date, fluoxetine-treated participants were 3.3 times more likely to be smoking (p = .02). Further research is warranted to determine why high-dose fluoxetine produces continuing effects that oppose tobacco abstinence.

Effect of nicotine on negative affect among more impulsive smokers.

In the present study, the authors tested the hypothesis that nicotine would provide greater relief from negative affect for more impulsive smokers than for less impulsive smokers. Euthymic adult smokers (N=70) participated in 2 laboratory sessions, during which they underwent a negative mood induction (music + autobiographical memory), then smoked either a nicotinized or de-nicotinized cigarette. Mixed-effects regression yielded a significant Impulsivity x Condition (nicotinized vs. de-nicotinized) x Time interaction. Simple effects analyses showed that heightened impulsivity predicted greater negative affect relief after smoking a nicotinized cigarette but not after smoking a de-nicotinized cigarette. These data suggest that nicotine may be a disproportionately powerful negative reinforcer for highly impulsive smokers, promoting higher levels of nicotine dependence and inhibiting smoking cessation.

The influence of personality and affect on nicotine dependence among male college students.

Many clinicians and researchers hypothesize that tobacco use disorders, regardless of the route of administration, are maintained by the ability of nicotine to regulate positive and negative mood states. The present study (N=137) examined whether certain mood states predicted dependence on either cigarettes or smokeless tobacco and whether specific personality characteristics (e.g., extraversion, neuroticism, and psychoticism) mediated these relationships among young male college students. Results indicated that positive and negative moods predicted cigarette dependence (p values=.01) and that neuroticism partially mediated the relationship between positive affect and cigarette dependence. Exploratory analyses revealed that positive affect also interacted with neuroticism to predict smokeless tobacco dependence (p=.04). Simple effects analyses revealed that this relationship was maintained only among individuals high in neuroticism. Results suggested that dependence on cigarettes and smokeless tobacco among male college students may have different affective correlates and that certain personality characteristics may enhance and explain the effects of mood on tobacco dependence.

Hedonic capacity, cigarette craving, and diminished positive mood.

Cigarette craving has been linked to elevated negative and positive moods, but a connection to deficient positive affect has not been studied. We tested whether a low hedonic capacity predicts a heightened urge to smoke after acute nicotine deprivation, and whether such an effect is mediated by decreased positive mood or increased negative mood. A total of 35 smokers characterized for individual differences in hedonic capacity were deprived of nicotine for 48 hr. Using mixed-effects regression modeling, we found that lower hedonic capacity predicted greater increases in craving 24 hr after nicotine withdrawal, t(29)=-2.33, p=.03. The effect of hedonic capacity on increased 24-hr postquit craving to smoke was fully mediated by decreased positive affect. Findings suggest that in early nicotine withdrawal, smokers with diminished capacity to experience pleasure have heightened susceptibility to cigarette cravings that arises because of decreased positive mood rather than increased negative mood.

Influence of fluoxetine on positive and negative affect in a clinic-based smoking cessation trial.

RATIONALE: Fluoxetine improves affect in clinical syndromes such as depression and premenstrual dysphoric disorder. Little is known about fluoxetine's influence on mood changes after quitting smoking, which often resemble sub-clinical depression. OBJECTIVES: The present study, a re-analysis of previously published data (Niaura et al. 2002), examined fluoxetine's effect on changes in negative and positive affect following quitting smoking. METHODS: Adult smokers (n=175) without clinically significant depression were randomized on a double-blind basis to receive fluoxetine hydrochloride (30 or 60 mg daily) or placebo for 10 weeks in combination with cognitive-behavioral therapy (CBT) for smoking cessation. We postulated that fluoxetine would beneficially influence post-cessation changes in positive and negative affect. RESULTS: Mood change across treatment was analyzed using mixed linear modeling controlling for initial level of nicotine dependence, plasma fluoxetine metabolites, and change in cotinine (a nicotine metabolite) at each visit. Relative to placebo, those on 60 mg fluoxetine experienced an elevation in positive affect that increased across time [t(526)=2.50, P=0.01], and a reduction in negative affect that returned to baseline across time [t(524)=2.26, P=0.02]. There were no differences between 30 mg and placebo on changes in positive or negative affect. CONCLUSIONS: Results indicate that 60 mg of fluoxetine improves both positive and negative mood states after quitting smoking and that diminished positive affect may be an overlooked affective response to smoking cessation.