The impact of nicotine lozenges and stimulus expectancies on cigarette craving

Cue-reactivity targeted smoking cessation intervention in individuals with tobacco use disorder: a scoping review

Objectives

Cue-reactivity is a critical step leading to the emergence of addictive psychology and the triggering of addictive behaviors within the framework of addiction theory and is considered a significant risk factor for addiction-related behaviors. However, the effect of cue-reactivity targeted smoking cessation intervention and the cue-reactivity paradigms used in the randomized controlled trials varies, which introduces more heterogeneity and makes a side-by-side comparison of cessation responses difficult. Therefore, the scoping review aims to integrate existing research and identify evidence gaps.

Methods

We searched databases in English (PubMed and Embase) and Chinese (CNKI and Wanfang) using terms synonymous with 'cue' and 'tobacco use disorder (TUD)' to April 2023, and via hand-searching and reference screening of included studies. Studies were included if they were randomized controlled trials taking cue-reactivity as an indicator for tobacco use disorder (TUD) defined by different kinds of criteria.

Results

Data were extracted on each study's country, population, methods, timeframes, outcomes, cue-reactivity paradigms, and so on. Of the 2,944 literature were retrieved, 201 studies met the criteria and were selected for full-text screening. Finally, 67 pieces of literature were selected for inclusion and data extraction. The results mainly revealed that non-invasive brain stimulation and exercise therapy showed a trend of greater possibility in reducing subjective craving compared to the remaining therapies, despite variations in the number of research studies conducted in each category. And cue-reactivity paradigms vary in materials and mainly fall into two main categories: behaviorally induced craving paradigm or visually induced craving paradigm.

Conclusion

The current studies are still inadequate in terms of comparability due to their heterogeneity, cue-reactivity can be conducted in the future by constructing a standard library of smoking cue materials. Causal analysis is suggested in order to adequately screen for causes of addiction persistence, and further explore the specific objective cue-reactivity-related indicators of TUD.

The impacts of caffeine administration, expectancies, and related stimuli on coffee craving, withdrawal, and self-administration

BACKGROUND

Caffeine is the most commonly consumed psychoactive substance, yet its potential reinforcing properties have been understudied.

AIMS

This study examined the impact of caffeine administration and expectancy on coffee-related craving, withdrawal, and cue reactivity via a balanced-placebo design.

METHODS

Following 18-h caffeine abstinence, 65 daily coffee consumers (54% male) received either caffeine-containing (100 mg) or placebo gum, along with either accurate or inaccurate information regarding the gum's caffeine content. Participants were exposed to neutral and coffee-related stimuli using different sensory modalities (visual and combined auditory/olfactory). Craving, withdrawal, and heart rate were assessed at baseline and after each cue presentation. Following the cue-reactivity assessments, participants were provided with an opportunity to self-administer units of coffee.

RESULTS

Caffeine expectancy was associated with reduced subjective withdrawal 30 min following the gum administration but was not significantly impacted by actual caffeine administration. The presentation of coffee-related cues was found to increase self-reported craving and heart rate, regardless of the expectation that caffeine had been administered. Visual, but not auditory/olfactory, cue reactivity appeared blunted when participants received a prior dose of caffeine. Prior caffeine ingestion also reduced the probability of subsequent coffee self-administration.

CONCLUSION

To our knowledge, this is the first examination of the impact of caffeine administration and expectancy on cue-elicited coffee craving and coffee consumption. Although there was some evidence that caffeine expectancy and administration were found to impact subjective withdrawal and self-administration respectively, neither was found to exert strong consistent effects on cue reactivity.

A Meta-Analysis of Cue Reactivity in Tobacco Cigarette Smokers

INTRODUCTION

The cue reactivity paradigm allows for systematic evaluation of motivational responses to drug-related cues that may elicit drug use. The literature on this topic has grown substantially in recent decades, and the methodology used to study cue reactivity has varied widely across studies. The present research provided a meta-analytic investigation of variables that have an impact on cue reactivity effects to enhance our understanding of this key feature of tobacco use disorders.

METHODS

A total of 128 publications yielded 249 effect sizes, which were analyzed to investigate the magnitude of the cue reactivity effect and potential moderators.

RESULTS

Craving generated a moderate-to-large effect size (Hedges' g = 0.71, p < .001), indicating that drug cues produced significantly greater craving than neutral cues. However, physiological variables yielded significantly lower or nonsignificant effect sizes. Analyses of a variety of empirically and theoretically relevant moderator variables showed that cue modality, cue personalization, cue reactivity environment, and the use of multiple assessments of cue reactivity were significantly associated with the magnitude of cue-specific craving effects (ps < .001). Effect sizes were not significantly related to abstinence status, gender, cigarettes per day, and treatment-seeking status.

CONCLUSIONS

The results underscored the strength of self-reported craving as an index of cue reactivity across studies, which support theories that posit cue reactivity is core to the addictive process for daily tobacco cigarette smokers. The present research further elucidates the variables that alter the cue reactivity effects across studies and provides recommendations for future cue reactivity research.

IMPLICATIONS

A core feature of addiction is that drug-related cues can have a major impact on motivational responses across multiple substance use disorders, including tobacco cigarettes. This paper describes a meta-analysis updating and synthesizing cue reactivity research with tobacco cigarette smokers over the last 20 years, a time of rapid growth for this literature. The study leads to a better understanding of the cue reactivity paradigm across different self-report and physiological variables and identifies factors that may modulate addictive motivation for tobacco cigarettes.

Effect of nicotine lozenge use prior to smoking cue presentation on craving and withdrawal symptom severity

BACKGROUND

Smokers are often advised to use nicotine lozenge after cravings or withdrawal symptoms are present, which may be too late to prevent lapses. This study assesses if lozenge use prior to smoking cue exposure attenuates cue-induced increases in symptom severity.

METHODS

In this randomized, cross-over study, participants completed three laboratory sessions at which they proceeded through 4 "rooms" in a virtual reality environment. The first and last "rooms" contained neutral cues and the others contained smoking cues. At one session, a 4 mg nicotine lozenge was not given until after cue exposure (to approximate current use: i.e., after craving and withdrawal symptoms occur). At the other two sessions either a nicotine or placebo lozenge was used 15 min before cue exposure procedures. Craving and withdrawal symptoms were measured throughout each laboratory session.

RESULTS

Of 58 participants randomized; 40 completed all 3 labs. Absolute levels of craving and withdrawal symptom severity during cue exposure were lower when placebo or active lozenge was used prior to cue presentation procedures vs. no treatment until after cue presentation procedures (all p-values <0.05). There were no differences among conditions in the magnitude of symptom severity increase occurring between the first neutral room and the cue rooms.

CONCLUSIONS

Lozenge use prior to cue exposure may minimize cue induced symptom severity but when taken 15 min prior to cues the decrease is not different than placebo. Research is needed to determine if another time-frame relative to cue exposure would be more effective.

The Influence of Placebo Effect on Craving and Cognitive Performance in Alcohol, Caffeine, or Nicotine Consumers: A Systematic Review

OBJECTIVE

The present systematic review aims to analyze the evidence about the influence of placebo effect on craving and cognitive performance in alcohol, caffeine, and nicotine consumers.

METHODS

Relevant studies were identified via Pubmed, Web of Science, and Scopus databases (up to March 2020). Only those papers published between 2009 and 2019 were searched.

RESULTS

Of the 115 preliminary papers, 8 studies of database search and 9 of the manual search were finally included in this review. Findings showed that while alcohol expectancies increased craving, caffeine and nicotine expectancies tend to decrease it. Alcohol expectancies caused similar or slower reaction time when alcohol was not consumed, impairments on inhibitory control (especially after alcohol consumption) and similar post-error slowing. The effect of caffeine and nicotine on reaction time has not been elucidated yet, however, caffeine expectancies have been shown to improve accuracy and the attentional filtering of distracting stimuli.

CONCLUSIONS

Alcohol, caffeine, and nicotine expectancies play an important role on craving. Although expectancies produce an effect on cognitive performance, caffeine and nicotine beliefs show an ambiguous impact on reaction time. Only the influence of alcohol expectancies on reaction time has been clarified. Furthermore, caffeine beliefs enhance accuracy.

The impacts of actual and perceived nicotine administration on insula functional connectivity with the anterior cingulate cortex and nucleus accumbens

BACKGROUND

Changes in resting state functional connectivity between the insula and dorsal anterior cingulate cortex as well as between the insula and nucleus accumbens have been linked to nicotine withdrawal and/or administration. However, because many of nicotine's effects in humans appear to depend, at least in part, on the belief that nicotine has been administered, the relative contribution of nicotine's pharmacological actions to such effects requires clarification.

AIMS

The purpose of this study was to examine the impacts of perceived and actual nicotine administration on neural responses.

METHODS

Twenty-six smokers were randomly assigned to receive either a nicotine inhaler (4 mg deliverable) or a nicotine-free inhaler across two sessions. Inhaler content instructions (told nicotine vs told nicotine-free) differed across sessions. Resting state functional connectivity between sub-regions of the insula and the dorsal anterior cingulate cortex and nucleus accumbens was measured using magnetic resonance imaging before and after inhaler administration.

RESULTS

Both actual and perceived nicotine administration independently altered resting state functional connectivity between the anterior insula and the dorsal anterior cingulate cortex, with actual administration being associated with decreased resting state functional connectivity, and perceived administration with increased resting state functional connectivity. Actual nicotine administration also contralaterally reduced resting state functional connectivity between the anterior insula and nucleus accumbens, while reductions in resting state functional connectivity between the mid-insula and right nucleus accumbens were observed when nicotine was administered unexpectedly. Changes in resting state functional connectivity associated with actual or perceived nicotine administration were unrelated to changes in subjective withdrawal and craving. Changes in withdrawal and craving were however independently associated with resting state functional connectivity between the nucleus accumbens and insula.

CONCLUSIONS

Our findings highlight the importance of considering non-pharmacological factors when examining drug mechanisms of action.

Investigating the role of expectancy in caffeine withdrawal using the balanced placebo design

OBJECTIVE

This study investigated psychological influences on drug withdrawal symptomatology using a caffeine-based model.

METHODS

Using the 2 × 2 balanced placebo design caffeine dose (given caffeinated vs decaffeinated coffee) was crossed with dose expectancy (told caffeine vs. decaf) among 87 (16-hr abstinent) regular coffee consumers in a 2-day study.

RESULTS

There were effects of expectancy and pharmacology that differed depending on the measure. Those told decaf reported greater caffeine cravings than those told caffeine 45 min and 8 hr postmanipulation. There were no expectancy effects on withdrawal symptoms or cognitive performance. There were pharmacological effects on all measures. Those given decaf reported greater withdrawal symptoms and showed poorer cognitive performance 45 min and 8 hr postmanipulation, with effects for headache and flu-like symptoms first emerging 8 hr postmanipulation (i.e., 24 hr abstinence in given decaf conditions). Caffeine readministration alleviated all withdrawal symptoms and cognitive decrements within 45 min. No drug by expectancy interactions were observed.

CONCLUSIONS

These findings confirm a strong pharmacological basis for caffeine withdrawal and an important role of cognition in drug craving. Future research should investigate the role of expectancy in drug withdrawal and craving and the potential use of expectancy manipulations in symptom prevention and management.

Quit Intentions Moderate Subjective and Physiological Responses to Acute Nicotine Replacement Therapy Administration in Dependent Smokers

Introduction

This study assessed the impact of expectancy and administration components of acute nicotine inhaler use on craving, heart rate, and smoking behavior in smokers with varying intentions to quit.

Methods

47 dependent smokers that differed in self-reported intention to quit (no intention to quit during the next month N = 26 vs. intention to initiate a quit attempt within 2 weeks N = 21) were randomly administered a 4 mg nicotine or nicotine-free inhaler across two sessions. Instructions regarding the inhaler's nicotine content (expect nicotine vs. expect nicotine-free; nicotine expectancy) and flavor (mint vs. citrus) varied across sessions. Craving and heart rate were assessed before and after inhaler administration (two-second inhalations every 10 seconds over 20 minutes). Next, participants were offered an opportunity to self-administer puffs of their preferred tobacco brand during an hour-long progressive ratio task.

Results

Across participants, nicotine expectancy independently reduced withdrawal related craving (p = .018), but no comparable effects of nicotine administration were evident. In quitting motivated smokers, nicotine expectancy and administration interacted to reduce intention to smoke (p = .040), while nicotine expectancy (p = .047) and administration (p = .025) independently reduced intention to smoke in quitting unmotivated smokers. Blunted heart rate reactivity to nicotine administration was observed in quitting motivated relative to unmotivated smokers (p = .042); however, neither expectancy nor administration impacted smoking behavior in either group (p values > .25).

Conclusions

Findings indicate that participant quitting intentions moderate acute nicotine replacement therapy responses. In quitting motivated smokers, a combination of pharmacological and psychological factors may be necessary for nicotine replacement therapy to impact craving.

Implications

Findings from this study demonstrate that motivations to quit smoking moderate subjective and physiological responses to acute nicotine administration and expectancy in dependent cigarette smokers. Quitting motivated smokers showed blunted heart rate reactivity to nicotine administration, suggesting that they may be less sensitive to the rewarding aspects of nicotine consumption. Nicotine administration and expectancy were found to interact to reduce craving in quitting motivated but not in unmotivated smokers, suggesting that pharmacological and psychological factors may be necessary for nicotine replacement therapy to impact craving in smokers who plan to quit.

Effects of smoking and paroxetine on stress-induced craving and withdrawal symptoms

Background

When smokers relapse, many cite stressful circumstances as the cause. Most smoking cessation medications do not prevent stress induced increases in craving and withdrawal symptom severity; however the effect of smoking prior to stress exposure on symptom severity is unclear.

Methods

We examined how smoking a cigarette immediately prior to a stressful task affects craving and withdrawal symptom severity by analyzing data from a double-blind, crossover study assessing paroxetine's effects on the physiological response to the combination of stress and smoking. Measures were obtained prior to and following smoking / stress exposure and following a subsequent 30 minute period at two laboratory sessions (i.e., after one month each of paroxetine and placebo).

Results

Among study completers (n=63), severity of craving decreased from the beginning of the session to immediately following the smoking / stress exposure (p<0.01) and severity of smoking urges decreased from the beginning to the end of the laboratory session (p<0.001). Withdrawal symptoms were less severe while taking paroxetine vs. placebo (p<0.05) but no treatment x time effects were observed.

Conclusions

Additional research is needed to identify interventions that could similarly decrease stress induced craving in order to determine if smoking cessation rates can be increased.

Timing of nicotine lozenge administration to minimize trigger induced craving and withdrawal symptoms

INTRODUCTION

Smokers are often advised to use nicotine lozenge when craving or withdrawal symptoms occur. This may be too late to prevent lapses. This study assessed if nicotine lozenge use prior to a common smoking trigger can minimize trigger induced increases in craving and withdrawal symptoms.

METHODS

Eighty-four smokers completed two laboratory sessions in random order. At one session, nicotine lozenge was given immediately after a stressor (to approximate current recommended use - i.e., after craving and withdrawal symptoms occur); at the other session subjects were randomized to receive nicotine lozenge at time points ranging from immediately to 30min prior to the stressor. Withdrawal symptoms and urge to smoke were measured using the Minnesota Nicotine Withdrawal Scale and the Questionnaire of Smoking Urges (QSU).

RESULTS

Relative to receiving lozenge after the stressor, a smaller increase in pre-stressor to post-stressor withdrawal symptom scores occurred when lozenge was used immediately (p=0.03) and 10min prior (p=0.044) to the stressor. Results were similar for factors 1 and 2 of the QSU when lozenge was used immediately prior to the stressor (p<0.03) and for factor 1 of the QSU when lozenge was used 10min prior to the stressor (p=0.028). Absolute levels of post-stressor withdrawal symptom and urge to smoke severity were lower when lozenge was given prior to versus after a stressor.

CONCLUSIONS

Administering the nicotine lozenge prior to a smoking trigger can decrease trigger induced craving and withdrawal symptoms. Future studies are needed to determine if such use would increase cessation rates. Clinicaltrials.gov # NCT01522963.

Attentional bias to smoking and other motivationally relevant cues is affected by nicotine exposure and dose expectancy

We investigated the effects of acute nicotine dose and expected dose on attentional bias (AB) to smoking and affective cues in overnight nicotine-deprived smokers (n=51; 24 women) using a balanced placebo design, which counterbalanced given nicotine dose (Given-NIC vs. Given-DENIC) with instructed nicotine dose expectancy (Told-NIC vs. Told-DENIC). Before and after smoking a study cigarette, smokers completed a vigilance task where they pressed buttons to every third consecutive even or odd digit, while ignoring intermittent smoking, pleasant, unpleasant, and neutral picture distracters. We examined the early posterior negativity (EPN) and late positive potential (LPP) components of the event-related potentials (ERPs) to the distracters, reaction time (RT) to the target digits, and ratings of the study cigarettes. The EPN was sensitive to both given and instructed nicotine dose, while the instructed dose moderated the impact of given dose for the LPP. The RT metrics were sensitive to given but not to instructed dose. The effects of given dose on ratings following cigarette smoking (e.g. enjoyment) were moderated by the instructed dose. The ERP findings suggest that the anticipated effects of nicotine improve attention much like receiving actual nicotine.

Does acute tobacco smoking prevent cue-induced craving?

BACKGROUND

Smoking cessation aids appear to be limited in their ability to prevent craving triggered by exposure to smoking-associated stimuli; however, the extent to which cue-induced cravings persist following denicotinized or nicotine-containing tobacco smoking is not known.

METHODS

Thirty (17 male) ⩾12-hour abstinent dependent smokers completed two sessions during which they smoked a nicotine-containing or denicotinized cigarette. Instructions regarding the nicotine content of the cigarette varied across sessions, and all participants were exposed to a neutral cue followed by a smoking cue after cigarette consumption. Craving was assessed before and after cigarette consumption and cue exposure.

RESULTS

Reduced intentions to smoke were associated with both nicotine expectancy (p<0.05) and nicotine administration (p<0.01), while reduced withdrawal-related craving was uniquely associated with nicotine administration (p<0.05). Smoking-associated stimuli increased craving regardless of nicotine expectancy or administration (p-values<0.001).

CONCLUSIONS

While both nicotine pharmacology and expectancy appear to contribute to craving reduction associated with acute tobacco smoking, neither smoking-related nicotine administration nor expectation prevents increases in craving following exposure to smoking-associated stimuli. These findings suggest that cue-induced craving may be resistant to various pharmacological and psychological interventions.

Experimentally induced states of mind determine abstinent smokers' level of craving in reaction to smoking-cues

Introduction

The present study aims to contribute to our knowledge on the causes of variations in experienced craving of (ex)smokers. The general idea is tested that when (ex)smokers are exposed to a smoking-cue, their level of craving is determined by the momentary state of mind through which the smoking-cue is interpreted.

Methods

A cue-reactivity paradigm in temporary abstinent smokers is applied to trigger craving responses under different experimentally induced states of mind. Craving is assessed with a three-item self-report measure. In study 1 (N = 120) a self-affirmation procedure is applied right before abstinent smokers were exposed to their own smoking paraphernalia. In study 2 (N = 140) abstinent smokers received bogus feedback inducing a high or low self-efficacy and strong or weak positive outcome expectations.

Results

Study 1 showed a significant interaction: When involvement was high, self-affirmation increased the level of craving but when involvement was low self-affirmation lowered craving. Study 2 also showed a significant interaction: Only when the positive outcome expectation of smoking were high, self-efficacy lowered the level of craving. All analyses were controlled for the number of cigarettes smoked a day and number of past quit attempts.

Conclusions

The present studies provide experimental evidence that levels of craving can be determined by momentary states of mind. This theoretical perspective can be integrated in existing conditioning and social cognitive learning perspectives on craving and substance use.

Smoking cue reactivity in current smokers, former smokers and never smokers

INTRODUCTION

Smoking related stimuli are known to increase both subjective craving and heart rate in smokers; however, little is currently known about the effects of such stimuli in former smokers.

METHODS

Subjective craving and heart rate were measured in 38 never smokers, 20 former smokers, and 30 current smokers exposed to video clips containing neutral and smoking related cues.

RESULTS

Compared with neutral cues, smoking cues significantly increased both heart rate and self-reported craving in current smokers, while in former smokers smoking cues were associated with a significant decrease in heart rate as well as with a relatively diminished increase in subjective craving. Neither craving nor heart rate was impacted by the smoking cues in never smokers.

CONCLUSIONS

Findings suggest that while smoking related stimuli continue to elicit modest subjective cravings in former smokers, there appears to be a marked change in the typical physiological response associated with such stimuli.

The impact of anticipated and unanticipated smoking opportunities on cigarette smoking and nicotine lozenge responses

BACKGROUND

Perceptions regarding the availability of smoking opportunities are known to affect cigarette craving; however, whether they impact actual smoking or how smokers respond to acute nicotine replacement therapy (NRT) administration is not known. This study examined the impact of pharmacological and expectancy components of NRT administration on craving and smoking in smokers anticipating or not anticipating an imminent smoking opportunity.

METHODS

In total, 154 smokers (84 male) completed an experimental session in which instructions regarding the nicotine content of a lozenge (4 mg vs. no nicotine) and regarding the availability of a future smoking opportunity were manipulated. Cigarette craving was assessed before and after manipulations and lozenge administration. All participants were then allotted 1h to self-administer as many cigarette puffs as they wished.

RESULTS

Unanticipated smoking opportunities reduced latency to self-administration (p<0.001), regardless of nicotine expectancy or pharmacology. When analyses included all participants, nicotine reduced intentions to smoke (p=0.016) and withdrawal-related craving (p=0.043) regardless of expectancy. Conversely, analyses using only "believers" of the nicotine content instructions revealed that nicotine expectancy reduced intentions to smoke (p=0.034) and withdrawal-related craving (p=0.047) regardless of actual nicotine administration. "Believers" also reported increased withdrawal-related craving when a smoking opportunity was perceived to be imminent (p=0.041). These effects were not significant when analyses included all participants.

CONCLUSIONS

Findings suggest that unexpected smoking opportunities may be more appealing than expected ones regardless of perceived or actual acute NRT use. They also highlight the importance of reporting balanced placebo findings using all participants as well as "believers" only.

Belief about nicotine selectively modulates value and reward prediction error signals in smokers

Little is known about how prior beliefs impact biophysically described processes in the presence of neuroactive drugs, which presents a profound challenge to the understanding of the mechanisms and treatments of addiction. We engineered smokers' prior beliefs about the presence of nicotine in a cigarette smoked before a functional magnetic resonance imaging session where subjects carried out a sequential choice task. Using a model-based approach, we show that smokers' beliefs about nicotine specifically modulated learning signals (value and reward prediction error) defined by a computational model of mesolimbic dopamine systems. Belief of "no nicotine in cigarette" (compared with "nicotine in cigarette") strongly diminished neural responses in the striatum to value and reward prediction errors and reduced the impact of both on smokers' choices. These effects of belief could not be explained by global changes in visual attention and were specific to value and reward prediction errors. Thus, by modulating the expression of computationally explicit signals important for valuation and choice, beliefs can override the physical presence of a potent neuroactive compound like nicotine. These selective effects of belief demonstrate that belief can modulate model-based parameters important for learning. The implications of these findings may be far ranging because belief-dependent effects on learning signals could impact a host of other behaviors in addiction as well as in other mental health problems.

The effects of nicotine stimulus and response expectancies on male and female smokers' responses to nicotine-free electronic cigarettes

BACKGROUND

Electronic cigarettes (e-cigarettes) have been reported to reduce tobacco craving and withdrawal; however, the mechanisms underlying these effects have not been elucidated.

METHODS

This study examined the contributions of nicotine stimulus and response expectancies to responses to nicotine-free e-cigarettes in 21 e-cigarette naïve smokers (12 male). Participants completed two randomized experimental sessions in which they administered a nicotine-free e-cigarette. During one session they were informed that the e-cigarette contained nicotine and during the other session they were informed that the e-cigarette was nicotine-free. Participants completed subjective assessments before and immediately after sampling ten puffs from the e-cigarette and were then invited to earn additional puffs using a computerized progressive ratio task. Prior to their enrolment in the study, participants provided an estimate of the relative importance of the nicotine content of e-cigarettes for craving relief.

RESULTS

Instructions that the e-cigarette contained nicotine were found to reduce both intention to smoke (p=0.017) and withdrawal-related (p=0.018) craving, regardless of a-priori reported beliefs regarding the relative importance of nicotine. Nicotine content instructions were also found to be associated with a shorter latency to self-administration (p=0.005); however, a Sex×Instructions×Response Expectancy interaction (p=0.008) revealed that this effect was specific to women who had strong a-priori nicotine content craving relief expectations. Neither nicotine content instructions nor response expectancies impacted the number of puffs self-administered.

CONCLUSIONS

Findings suggest that nicotine content expectations contribute to smokers' responses to e-cigarettes, and that a-priori beliefs about nicotine effects may be especially important in women.

The effects of beliefs regarding drug assignment in experimental and field studies of nicotine delivery devices: a review

The placebo effect of a psychoactive drug can be defined as the effect of expecting the drug in the absence of its pharmacological actions. As nicotine is widely believed to be the primary factor driving cigarette smoking, smokers are likely to expect nicotine to alleviate craving and withdrawal. The present review examines the extent to which any observed effects of nicotine, and especially its craving- and withdrawal-reducing effects, can be attributed to placebo. We begin by reviewing studies that examined the placebo effects of nicotine in the laboratory and follow with a review of potential placebo effects that are typically not controlled in placebo-controlled studies of nicotine replacement therapy (NRT). In laboratory studies, nicotine instructions decrease tobacco smoking, craving and/or withdrawal, while nicotine-specific effects have not been consistently reported. In field trials of NRT, there is a general failure to assess smokers' beliefs regarding their drug assignment. This omission makes it difficult to unequivocally attribute findings of placebo-controlled NRT studies to the physiological effects of nicotine. In sum, our review indicates that the placebo effects of nicotine, and specifically nicotine content expectations, may account for many of the benefits associated with nicotine delivery devices in both laboratory and field studies.