Re-examination of arousing and de-arousing effects of cigarette smoking

A double blind, placebo-controlled study of the effects of post-retrieval propranolol on reconsolidation of memory for craving and cue reactivity in cocaine dependent humans

RATIONALE/OBJECTIVES

This study examined the effects of propranolol vs. placebo, administered immediately after a "retrieval" session of cocaine cue exposure (CCE), on craving and physiological responses occurring 24 h later during a subsequent "test" session of CCE. It was hypothesized that compared to placebo-treated cocaine-dependent (CD) individuals, propranolol-treated CD individuals would evidence attenuated craving and physiological reactivity during the test session. Secondarily, it was expected that group differences identified in the test session would be evident at a 1-week follow-up CCE session. Exploratory analyses of treatment effects on cocaine use were also performed at follow-up.

METHODS

CD participants received either 40 mg propranolol or placebo immediately following a "retrieval" CCE session. The next day, participants received a "test" session of CCE that was identical to the "retrieval" session except no medication was administered. Participants underwent a "follow-up" CCE session 1 week later. Craving and other reactivity measures were obtained at multiple time points during the CCE sessions.

RESULTS

Propranolol- vs. placebo-treated participants evidenced significantly greater attenuation of craving and cardiovascular reactivity during the test session. Analysis of the follow-up CCE session data did not reveal any group differences. Although there was no evidence of treatment effects on cocaine use during follow-up, this study was insufficiently powered to rigorously evaluate differential cocaine use.

CONCLUSIONS

This double-blind, placebo-controlled laboratory study provides the first evidence that propranolol administration following CCE may modulate memories for learning processes that subserve cocaine craving/cue reactivity in CD humans. Alternative interpretations of the findings were considered, and implications of the results for treatment were noted.

Haemodynamic reactions to acute psychological stress and smoking status in a large community sample

Exaggerated haemodynamic reactions to acute psychological stress have been implicated in a number of adverse health outcomes. This study examined, in a large community sample, the cross-sectional associations between haemodynamic reactivity and self-reported smoking status. Blood pressure and heart rate were measured at rest and in response to a 3-minute arithmetic stress task. Participants were classified as current, ex-, or non-smokers by their response to a simple prompt. Smokers had significantly smaller SBP and DBP reactions to acute stress than ex- and non-smokers; current and ex-smokers had lower HR reactivity. These effects remained significant following adjustment for a host of variables likely to be associated with reactivity and/or smoking. Although the act of smoking acutely increases haemodynamic activity, the present findings contribute to a growing body of literature showing that smokers have blunted reactivity to mental stress. They also support the hypothesis that blunted reactivity may be characteristic of a range of dependencies. The present results also suggest that smoking status needs to be considered in the design and analysis of stress reactivity studies.

Differences in ERP topographies during color matching of smoking-related and neutral pictures in smokers and non-smokers

The concept of a specific memory network that drives addictive behavior has often been discussed in relation to the phenomenon of sudden relapse into addiction after years of abstinence. But there is still a lack of data that shows a link between drug-related cue processing and specific changes of behavior in addicts. In the present study we investigated the relationship between smoking-related picture processing, performance in a color matching task, and ERP topographies. Fifteen smokers and 19 non-smoking participants performed a color matching task including monochromic pictures with smoking-related and neutral content. Smokers and non-smokers showed remarkable differences between stimulus category-related ERP topographies. Furthermore, both smokers and non-smokers showed increased reaction times during color matching when the picture contents were related to smoking behavior. The results are discussed with respect to different drug-cue-related patterns of information processing in smokers and non-smokers.

Facial EMG as an index of affective response to nicotine

Negative affect reduction has been postulated to be a key feature of cigarette smoking. In the present study, facial electromyography (EMG), heart rate (HR), and skin conductance response (SCR) were used to evaluate the affective significance of acute nicotine administration and overnight withdrawal. Smokers (N = 115) attended four 90-min laboratory assessment sessions scheduled approximately 3 days apart. The sessions provided a complete crossing of 2 prelaboratory deprivation conditions (12-hr deprived vs. nondeprived) with 2 drug conditions (nicotine vs. placebo nasal spray). During each session, smokers viewed affective slides while facial EMG, HR, and SCR were recorded. Results indicated that for women, nicotine nasal spray resulted in lower corrugator EMG activity during both smoking-deprived and nondeprived sessions, compared with placebo. However, nondeprived women also showed an increase in zygomaticus EMG when given nicotine compared with placebo spray, whereas smoking-deprived women demonstrated a decrease in the zygomaticus response to nicotine compared with placebo. With men, nicotine also appeared to lower corrugator during deprivation, but not nondeprivation, compared with placebo spray, though the contrast only approached significance. With zygomaticus EMG, nicotine spray decreased men's zygomaticus responding during nondeprivation but not during deprivation, compared with placebo spray. The HR results reflected the stimulatory properties of the drug rather than nicotine's affective properties, whereas SCR was unresponsive to our experimental manipulations. The corrugator EMG results support negative reinforcement models of smoking that postulate that acute nicotine use reduces withdrawal-driven negative affect.

Direct and indirect effects of nicotine/smoking on cognition in humans

Acute nicotine administration and acute nicotine withdrawal have been shown to have effects on mood, arousal, and cognition in humans. However, given what is known about the interrelationships between mood, arousal, and cognition in the psychology literature, it is unclear to what extent these effects on a given response are direct, or mediated through other responses (indirect). This article discusses this issue with particular emphasis on the question of whether nicotine has direct effects on cognition. Five ways are suggested as to how this question can be resolved, the relevant literature is reviewed, and some research ideas are proposed.

An acute dose of nicotine enhances cue-induced cocaine craving

The present study examined whether the active component in tobacco, nicotine, can modulate cocaine craving in patients with a history of smoking crack cocaine when exposed to crack cocaine related environmental cues. Twenty patients, all cigarette smokers, were randomly assigned to nicotine (two 22 mg transdermal patches) or placebo in a single-dose, placebo-controlled, crossover, double-blind study. Craving and anxiety were measured before and after cocaine cues with visual analog scales for desire to use cocaine and mood. Skin conductance and skin temperature were recorded before and during cocaine cues. Following exposure to cocaine cues, all patients reported an increase in cocaine craving and anxiety relative to the pre-cue measures. Cue exposure also produced an increase in skin conductance and decrease in skin temperature. The cue-induced increase in cocaine craving was strongly enhanced by nicotine, while the increase in anxiety was slightly augmented. Cue-induced skin conductance and temperature responses were unaffected by nicotine. These findings show that cue-induced cocaine craving is enhanced by nicotine. This occurred in the absence of any tobacco smoking-related cues, suggesting that nicotine may have direct psychopharmacological effects on conditioned cocaine craving.

The effects of recent food, alcohol, and tobacco intake and the temporal scheduling of testing on cardiovascular activity at rest and during psychological stress

Participants in cardiovascular psychophysiological studies receive various instructions regarding restraints on alcohol, food, and tobacco intake prior to testing. Further, although the hour of testing is frequently a concern, little attention is paid to month of the year. In the present study, we examined cardiovascular activity at rest and in response to a laboratory stress task in 1,272 men in terms of these variables. Alcohol consumption among alcohol users and food intake within 4 hr of testing were associated with higher baseline diastolic blood pressure (BP) but lower baseline heart rate (HR). Tobacco use in smokers within 1 hr of testing was associated with elevated baseline BP and HR. Hour of testing was related to baseline HR, whereas month of the year was associated with baseline BP. In contrast to these baseline effects, cardiovascular reactions to the laboratory stress task were largely immune to these contextual influences.