Medication screening for smoking cessation: a proposal for new methodologies

A practice quit model to test early efficacy of medications for alcohol use disorder in a randomized clinical trial

RATIONALE

Screening novel medications for alcohol use disorder (AUD) requires models that are both efficient and ecologically-valid. Ideally, such models would be associated with the outcomes of a given medication in clinical trials.

OBJECTIVES

To test a novel human laboratory model in which individuals with intrinsic motivation to change their drinking engage in a "practice quit" attempt consisting of 6 days of complete abstinence from alcohol.

METHOD

Individuals with current AUD completed a randomized, double-blind, placebo-controlled study of naltrexone (50 mg), varenicline (2 mg bid), or matched placebo. Participants were titrated onto the study medication for 1 week prior to starting the 6-day practice quit attempt. During the practice quit attempt, participants completed daily interviews with research staff. All participants completed an alcohol cue-exposure paradigm before starting the study medication and after 2 weeks of study medication.

RESULTS

There were no significant medication effect on drinks per drinking day (F(2,49) = 0.66, p = 0.52) or percent days abstinent (F(2,49) = 0.14, p = 0.87) during the 6-day practice quit period. There were no medication effects on alcohol cue-reactivity (F(2,44) = 0.80, p = 0.46). Notably, participants sharply reduced their drinking during the entire 13-day medication treatment period, as compared to reducing only during the 6-day practice quit period. During the total medication period, higher levels of motivation to change was associated with higher percent days abstinent (F(1,49) = 8.12, p < 0.01).

CONCLUSIONS

This study reports mostly null findings, which challenges us to decompose its nuanced design to consider model refinements. Possible changes to the model include considering the requirement for intrinsic motivation for change, including a longer practice quit period, encompassing the medication administration timeframe in the practice quit period, increasing the required sample size for signal detection, and examining a post COVID-19 pandemic cohort.

The 2022 Ferno Award Address: CrEATE, an Efficient Crossover Evaluation of Addiction Treatment Efficacy

Dozens of drugs have been evaluated in recent decades for initial evidence of efficacy to aid smoking cessation (i.e. "early Phase 2" testing, according to U.S. FDA terminology), with the vast majority failing to show efficacy. Even small randomized clinical trials (RCTs), the most common early Phase 2 tests, are costly undertakings, made more unappealing by their high likelihood of failure. At the same time, another early Phase 2 approach, acute tests of drug effects on surrogate endpoints such as withdrawal or craving severity, are more practical but have little predictive clinical validity. Described here is an innovative procedure that optimally combines the validity of clinical trials with the practical advantages of surrogate endpoint studies to more efficiently determine whether or not a novel drug warrants continued clinical development. This CrEATE procedure, or Crossover Evaluation of Addiction Treatment Efficacy, does so by assessing short-term quit success in smokers highly motivated to quit when briefly treated with active drug versus placebo in a crossover design, so that quit efficacy from both conditions is compared within participants. The program to develop and evaluate CrEATE demonstrates its sensitivity to efficacy from all three FDA-approved first-line cessation medications (NRT, varenicline, bupropion), tested here as model drugs, as well as specificity in identifying lack of efficacy with a drug known to be ineffective for cessation (modafinil). CrEATE has subsequently been used to evaluate a few novel interventions, concluding they lack efficacy in increasing quit success. Future directions for the potential utility of CrEATE are provided. Implications: The ability of CrEATE to reach a Go/No Go decision more quickly and with far less cost lowers the risk of failure, meaning widespread use of the procedure should encourage the evaluation of more novel candidate drugs. With its greater efficiency, failed tests, unfortunately the most likely outcome in early Phase 2 studies, will cause less waste of resources. At the same time, CrEATE tests that indicate a novel treatment has efficacy will justify the substantial time and expense of moving forward to evaluate the drug in late Phase 2 RCTs.

Evaluating Treatment Mechanisms of Varenicline: Mediation by Affect and Craving

INTRODUCTION

Negative reinforcement models posit that relapse to cigarette smoking is driven in part by changes in affect and craving during the quit attempt. Varenicline may aid cessation by attenuating these changes; however, this mediational pathway has not been formally evaluated in placebo-controlled trials. Thus, trajectories of negative affect (NA), positive affect (PA), and craving were tested as mediators of the effect of varenicline on smoking cessation.

AIMS AND METHODS

Secondary data analysis was conducted on 828 adults assigned to either varenicline or placebo in a randomized controlled trial for smoking cessation (NCT01314001). Self-reported NA, PA, and craving were assessed 1-week pre-quit, on the target quit day (TQD), and 1 and 4 weeks post-TQD.

RESULTS

Across time, NA peaked 1-week post-quit, PA did not change, and craving declined. Less steep rises in NA (indirect effect 95% CI: .01 to .30) and lower mean craving at 1-week post-quit (CI: .06 to .50) were mediators of the relationship between varenicline and higher cessation rates at the end of treatment. PA was associated with cessation but was not a significant mediator.

CONCLUSIONS

These results partially support the hypothesis that varenicline improves smoking cessation rates by attenuating changes in specific psychological processes and supported NA and craving as plausible treatment mechanisms of varenicline.

IMPLICATIONS

The present research provides the first evidence from a placebo-controlled randomized clinical trial that varenicline's efficacy is due, in part, to post-quit attenuation of NA and craving. Reducing NA across the quit attempt and craving early into the attempt may be important treatment mechanisms for effective interventions. Furthermore, post-quit NA, PA, and craving were all associated with relapse and represent treatment targets for future intervention development.

Combined Working Memory Training and Transcranial Magnetic Stimulation Demonstrates Low Feasibility and Potentially Worse Outcomes on Delay to Smoking and Cognitive Tasks: A Randomized 2 × 2 Factorial Design Pilot and Feasibility Study

INTRODUCTION

Repetitive Transcranial Magnetic Stimulation (rTMS) has shown promising results in treating several Substance Use Disorders including Tobacco Use Disorder. However, questions remain regarding how to optimize treatment outcomes. Enhancement of working memory by rTMS is a potential therapeutic mechanism. The current pilot study examined whether rTMS plus a cognitive training program could enhance the effects of rTMS on smoking behaviors using a controlled, factorial design.

AIMS AND METHODS

We hypothesized that cognitive training plus stimulation would improve control over smoking behaviors, resulting in enhanced cognitive performance and increased latency to smoke on a delay to smoking analog task. Using a 2 × 2 factorial design, nicotine dependent smokers (n = 43) were randomized to receive 10 sessions of active (10 Hz) or sham rTMS delivered to the left dorsolateral prefrontal cortex, plus active or sham working memory training (WMT) prior to and following stimulation.

RESULTS

Contrary to hypotheses, we observed a significant interaction effect, indicating that combining the two active interventions (rTMS+WMT) resulted in worse performance on the smoking analog task (B = -33.0, 95% CI = -64.39, -1.61, p < .05), compared to delivering either intervention alone. Additionally, although active rTMS (compared to sham rTMS) improved letter-sequencing performance (B = 1.23, 95% CI = 0.08-2.38, p < .05), and active WMT (compared to sham WMT) improved back-digit task performance (B = 1.53, 95% CI = 0.02-3.05, p < .05), combining interventions worsened the effect of each on a back-digit task (B = -3.01, 95% CI = -5.96, -0.052, p < .05).

CONCLUSIONS

These preliminary findings indicate potential iatrogenic effects of combining rTMS and this working memory training intervention and underscore the need for rigorous evaluation of substance specific conceptual frameworks when selecting future combination interventions.

IMPLICATIONS

Counter to hypothesis, this study found no additional benefit of adding a working memory training program to a rTMS protocol in a sample of daily smokers. The combination condition (active rTMS + active training) resulted in worse performance on a delay to smoking analog task and a measure of working memory performance compared to delivering either intervention alone. These preliminary findings inform strategies for optimizing rTMS in smokers and highlight the need for future studies to consider several key components of candidate combination interventions, including effects on regulation of substance use.

CLINICAL TRIAL REGISTRATION (IF ANY)

The trial was registered at ClinicalTrials.gov (NCT03337113).

Factors associated with baseline smoking self-efficacy among male Qatari residents enrolled in a quit smoking study

Smoking self-efficacy, described as confidence in one’s ability to abstain from smoking in high-risk situations is a key predictor in cessation outcomes; however, there is a dearth of research on factors that influence self-efficacy surrounding smoking behavior. This study examines factors associated with baseline self-efficacy among treatment seeking participants enrolled in a pilot feasibility smoking cessation study. Participants (n = 247) were daily male smokers, residents of Doha in Qatar (18–60 years) who were enrolled in a telephone-based smoking cessation study. Baseline assessments included self-efficacy, home smoking rules, socio-demographic variables, smoking history, and psychosocial characteristics. Factors associated with self-efficacy were assessed using multiple linear regression analysis. Results showed that after controlling for relevant variables, number of cigarettes smoked (β^ = -0.22; 95% CI: -0.37, -0.06), having at least one quit attempt in the past year (β^ = 2.30; 95% CI: 0.27, 4.35), and reporting a complete home smoking ban (β^ = 3.13; 95% CI: 0.56, 5.70) were significantly associated with higher self-efficacy to quit smoking. These results provide data-driven indication of several key variables that can be targeted to increase smoking self-efficacy in this understudied population.

Modeling the effect of stress on vaping behavior among young adults: A randomized cross-over pilot study

BACKGROUND

Laboratory models have been useful in identifying the motivational processes underlying tobacco use. This pilot study aimed at (1)validating a human laboratory model initially developed for smokers to e-cigarette users; (2)applying this model to examine the effects of stress on the reinforcing value of nicotine among young adults.

METHODS

Using a randomized cross-over design, young e-cigarette users (n = 30) who were nicotine deprived were exposed to a stress or a non-stress task, and then engaged in a laboratory task assessing vaping's reward value on two separate days. During the first part of the task, participants had the option of initiating an e-cigarette self-administration session or delaying initiation for up to 50 min in exchange for money. During the second part of the task, participants chose between vaping or receiving money. The length of the delay and the number of e-cigarette uses consumed were the primary outcomes. Craving and puff topography were secondary outcomes.

RESULTS

There was no difference in the length of time that participants were able to refrain from vaping in the stress and control task (p = .90). Participants purchased and consumed more puffs after being exposed to the stress task compared to the control task (p<.001), puff topography and craving were unaffected.

CONCLUSIONS

Exposure to a stressor did not undermine the ability to resist vaping among deprived e-cigarette users (first part), but it influenced the number of uses purchased once users decided to vape (second part). This study evidences that these two parts of the task for assessing reward value are differentially sensitive to the stress manipulation.

Defining and Measuring Abstinence in Clinical Trials of Smoking Cessation Interventions: An Updated Review

BACKGROUND

Changes in tobacco products, use patterns, and assessment technology in the last 15 years led the Society for Research on Nicotine and Tobacco (SRNT) Treatment Research Network to call for an update to the 2003 SRNT recommendations for assessing abstinence in clinical trials of smoking cessation interventions.

METHODS

The SRNT Treatment Research Network convened a group of investigators with decades of experience in conducting tobacco treatment clinical trials. To arrive at the updated recommendations, the authors reviewed the recommendations of the prior SRNT Workgroup as well as current literature. Ten additional experts in the field provided feedback on this paper and these recommendations.

RESULTS

With respect to defining abstinence, the authors recommend: (1) continuing to use the definition of no use of combustible tobacco products (regardless of use of noncombustible tobacco products [e.g., snus] and alternative products [e.g., e-cigarettes]) and collecting additional data to permit alternate abstinence definitions; (2) no use of combustible or smokeless tobacco products; and (3) no use of combustible or smokeless tobacco products or alternative products, as appropriate for the research question being addressed. The authors also recommend reporting point prevalence and prolonged abstinence at multiple timepoints (end of treatment, ≥3 months after the end of treatment, and ≥6 months postquit or posttreatment initiation).

CONCLUSIONS

Defining abstinence requires specification of which products a user must abstain from using, the type of abstinence (i.e., point prevalence or continuous), and the duration of abstinence. These recommendations are intended to serve as guidelines for investigators as they collect the necessary data to accurately describe participants' abstinence during smoking cessation clinical trials.

IMPLICATIONS

This paper provides updated recommendations for defining abstinence in the context of smoking cessation treatment clinical trials.

Differences in Sociodemographic and Alcohol-Related Clinical Characteristics Between Treatment Seekers and Nontreatment Seekers and Their Role in Predicting Outcomes in the COMBINE Study for Alcohol Use Disorder

BACKGROUND

One of the challenges in early-stage clinical research aimed at developing novel treatments for alcohol use disorder (AUD) is that the enrolled participants are heavy drinkers, but do not seek treatment for AUD.

AIMS

To compare nontreatment seekers with alcohol dependence (AD) from 4 human laboratory studies conducted at Brown University (N = 240; 65.4% male) to treatment seekers with AD from the multisite COMBINE study (N = 1,383; 69.1% male) across sociodemographic and alcohol-related clinical variables and to evaluate whether the variables that significantly differentiate the 2 samples predict the 3 main COMBINE clinical outcomes: time to relapse, percent days abstinent (PDA), and good clinical outcome.

METHODS

Sample characteristics were assessed by parametric and nonparametric testing. Three regression models measured the association between the differing variables and the 3 main COMBINE clinical outcomes.

RESULTS

The nontreatment seekers, compared to the treatment seekers, were more ethnically diverse, less educated, single, and working part-time or unemployed (p's < 0.05); they met fewer DSM-IV AD criteria and had significantly lower scores on alcohol-related scales (p's < 0.05); they were less likely to have a father with alcohol problems (p < 0.0001) and had a significantly earlier age of onset and longer duration of AD (p's < 0.05); they also had significantly more total drinks, drinks per drinking day, heavy drinking days (HDD), and lower PDA in the 30 days prior to baseline (p's < 0.0001 to <0.05). Having more HDD in the 30 days prior to baseline predicted all of the 3 COMBINE clinical outcomes. All the other characteristics mentioned above that differed significantly between the 2 groups predicted at least 1 of the 3 COMBINE clinical outcomes, except for level of education, age of onset, and duration of AD.

CONCLUSIONS

The observed differences between groups should be considered in efforts across participant recruitment at different stages of the development of new treatments for AUD.

Severity of negative mood and anxiety symptoms occurring during acute abstinence from tobacco: A systematic review and meta-analysis

This review was conducted with the following goals: To quantify the severity of mood and anxiety symptoms emerging during acute abstinence from tobacco (1). To explore sex differences related to the experience of specific symptoms (2). To investigate the early time course of symptoms (3). A meta-analysis was performed from 28 studies assessing mood and anxiety symptoms during the earliest phases of tobacco abstinence (up to 24 hrs post-quit) conducted from 1999 to 2019. Results revealed a significant (p < 0.0001) increase in 'anxiety', 'anger/irritability', 'depressed mood /sadness', and composite negative affect ('NA') in the 24 hours following smoking cessation. The largest effect size was detected for 'anxiety' (0.63). A qualitative analysis was performed to investigate sex differences and the time course of the specific symptoms. Results indicated that female smokers may experience worse mood symptoms compared to male smokers and that these symptoms may emerge within 3 hrs post-quit. Smoking cessation programs should implement sex-tailored interventions in order to improve their effectiveness, while future research should focus on alternative methods of nicotine administration.

Non-pharmacological Considerations in Human Research of Nicotine and Tobacco Effects: A Review

Human research of nicotine and tobacco effects demonstrates that non-pharmacological factors may systematically affect responses to administered substances and inert placebos. Failure to measure or manipulate these factors may compromise study reliability and validity. This is especially relevant for double-blind placebo-controlled research of nicotine, tobacco, and related substances. In this article, we review laboratory-based human research of the impact of non-pharmacological factors on responses to tobacco and nicotine administration. Results suggest that varying beliefs about drug content and effects, perceptions about drug use opportunities, and intentions to cease drug use systematically alter subjective, behavioral, and physiological responses to nicotine, tobacco, and placebo administration. These non-pharmacological factors should be considered when designing and interpreting the findings of human research of nicotine and tobacco effects, particularly when a double-blind placebo-controlled design is used. The clinical implications of these findings are discussed, and we propose methodological strategies to enhance the reliability and validity of future research.

IMPLICATIONS

Growing research demonstrates that non-pharmacological factors systematically alter responses to acute nicotine, tobacco, and placebo administration. Indeed, varying beliefs about nicotine and/or tobacco administration and effects, differing perceptions about nicotine and/or tobacco use opportunities, and inconsistent motivation to quit smoking have been found to exert important influences on subjective, physiological, and behavioral responses. These variables are infrequently measured or manipulated in nicotine and tobacco research, which compromises the validity of study findings. Incorporating methodological strategies to better account for these non-pharmacological factors has the potential to improve the quality of addiction research and treatment.

A randomized, double-blind, placebo-controlled study of the kappa opioid receptor antagonist, CERC-501, in a human laboratory model of smoking behavior

Preclinical data indicate that selective kappa opioid receptor antagonists reduce nicotine self-administration and withdrawal symptoms. The aim of the current study was to determine whether treatment with CERC-501, an orally available, potent, and selective kappa opioid receptor antagonist, could alleviate nicotine withdrawal and craving and mitigate mood alterations associated with nicotine withdrawal in humans. Healthy, adult cigarette smokers were enrolled into this randomized, multisite, double-blind, placebo-controlled, crossover study. Participants completed two 8-day treatment phases during which they received either CERC-501 (15 mg, p.o., once daily) or placebo. On the seventh day of each dosing phase, participants were admitted as inpatients for an 18-hour cigarette abstinence period followed by experimental testing. The primary outcome measures were (a) performance on the McKee Smoking Lapse test (ie, latency to smoke in exchange for money) and (b) number of cigarettes self-administered during a 60-minute ad lib smoking period. Other outcomes included measures of craving, mood, anxiety, nicotine withdrawal, and subjective effects of cigarette smoking. A total of 71 participants who smoked an average of approximately 23 cigarettes per day were enrolled, and 56 subjects completed the study. CERC-501 was well tolerated, but it did not significantly alter the latency to start smoking (CERC-501: 16.5 min vs placebo: 17.7 min) or the number of cigarettes smoked (CERC-501: 3.3 cigarettes vs placebo: 3.1 cigarettes). Compared with placebo, CERC-501 also did not affect cigarette craving, mood, anxiety, nicotine withdrawal, or subjective effects of smoking. These findings do not support a role for CERC-501 in the treatment of nicotine use disorder.

Nicotine Addiction: Neurobiology and Mechanism

Nicotine, primary component of tobaco produces craving and withdrawal effect both in humans and animals. Nicotine shows a close resemblance to other addictive drugs in molecular, neuroanatomical and pharmacological, particularly the drugs which enhances the cognitive functions. Nicotine mainly shows its action through specific nicotinic acetylcholine receptors located in brain. It stimulates presynaptic acetylcholine receptors thereby enhancing Ach release and metabolism. Dopaminergic system is also stimulated by it, thus increasing the concentration of dopamine in nuclear accumbens. This property of nicotine according to various researchers is responsible for reinforcing behavioral change and dependence of nicotine. Various researchers have also depicted that some non dopaminergic systems are also involved for rewarding effect of nicotinic withdrawal.

Neurological systems such as GABAergic, serotonergic, noradrenergic, and brain stem cholinergic may also be involved to mediate the actions of nicotine. Further, the neurobiological pathway to nicotine dependence might perhaps be appropriate to the attachment of nicotine to nicotinic acetylcholine receptors, peruse by stimulation of dopaminergic system and activation of general pharmacological changes that might be responsible for nicotine addiction. It is also suggested that MAO A and B both are restrained by nicotine. This enzyme helps in degradation dopamine, which is mainly responsible for nicotinic actions and dependence. Various questions remain uninsurable to nicotine mechanism and require more research. Also, various genetic methods united with modern instrumental analysis might result for more authentic information for nicotine addiction.

Possible New Symptoms of Tobacco Withdrawal II: Anhedonia-A Systematic Review

INTRODUCTION

When animals undergo nicotine deprivation, rewards become less rewarding (ie, anhedonia occurs). We searched for tests of whether anhedonia occurs in abstinent smokers.

METHODS

The major inclusion criterion was a within-participants comparison of behavioral measures of reward sensitivity or self-reported anhedonia during smoking versus during abstinence among daily smokers. A computerized search of PubMed, PsychInfo, and Cochrane databases and other methods located 13 studies. All but one were laboratory studies.

RESULTS

The number of studies and participants were small and the results mixed. In terms of anticipatory anhedonia (ie, wanting a reward), abstinence appeared to decrease willingness to work for immediately available rewards, but did not appear to influence how much adding rewards to a task increased responding. Abstinence also appeared to produce small increases in self-reported anticipatory anhedonia. In terms of consummatory anhedonia (ie, liking a reward), self-report measures found anhedonia decreased pleasure from rewards in some but not all tests. In terms of learning (ie, learning to choose a more frequent reward), abstinence did not reliably decrease allocating responding to high versus low frequency reward options.

CONCLUSIONS

Although results were mixed, abstinence appears to increase anticipatory anhedonia. It is unclear if abstinence increases consummatory or reward learning-based anhedonia. Further studies of anhedonia in clinical settings are needed (1) to estimate the reliability and clinical significance of anhedonia as a symptom of tobacco withdrawal, (2) to assess if effects represent withdrawal versus offset processes, and (3) to assess if anhedonia interferes with the ability to stop smoking.

IMPLICATIONS

Anticipatory anhedonia appears to be a symptom of tobacco withdrawal and should be added to tobacco withdrawal checklists and diagnostic criteria. Further study of consummatory and learning-based anhedonia is warranted.

The development and validation of a human screening model of tobacco abstinence

INTRODUCTION

Given the low efficacy of smoking cessation methods, an experimental medicine model indicating smoking abstinence would be of great benefit to the development of new treatments. Hence the sensitivity of cognitive tasks and ambulatory craving measures to smoking abstinence were investigated.

METHODS

Cognitive tasks and ambulatory ratings of craving were assessed for sensitivity to acute abstinence (experiment 1), and nicotine replacement therapy administration (NRT) (experiment 2).

RESULTS

In experiment 1 go/no-go performance was improved (Mean Difference [MD] -0.99, 95% CI: -1.90 to -0.08) and craving was lower (Regression Coefficient [RC] -33.39, 95% CI: -39.96 to -26.82) in satiated compared with abstinent smokers. There was no clear evidence that N-back (MD 0.64, 95% CI: -0.42 to 2.51), delay discounting (MD 0.01, 95% CI: 0.001 to 0.005) or dot probe performance (MD 0.61, 95% CI: -0.87 to 1.54) were sensitive to acute abstinence. In experiment 2 go/no-go performance was improved (MD 1.12, 95% CI: 0.16-2.08) and craving was lower (RC -18.59, 95% CI: -24.63 to -12.55) smokers abstinent overnight receiving NRT compared with placebo. There was no clear evidence that N-back (MD -0.25, 95% CI: -1.45 to 0.94), delay discounting (MD 0.01, 95% CI: -0.002 to 0.004) or dot probe performance (MD -0.49, 95% CI: -1.61 to -0.64) were sensitive to NRT.

CONCLUSIONS

Findings from two experiments converge to suggest that abstinence in smokers reliably increases ambulatory craving assessments and, to a lesser extent, decreases go/no-go task performance. These findings can be utilized in the development of an experimental medicine model to test novel treatments for smoking cessation.

The Acute Effects of a Dopamine D3 Receptor Preferring Agonist on Motivation for Cigarettes in Dependent and Occasional Cigarette Smokers

Background

Dopaminergic functioning is thought to play critical roles in both motivation and addiction. There is preliminary evidence that dopamine agonists reduce the motivation for cigarettes in smokers. However, the effects of pramipexole, a dopamine D3 receptor preferring agonist, have not been investigated.

The aim of this study was to examine the effects of an acute dose of pramipexole on the motivation to earn cigarettes and nondrug rewards.

Methods

Twenty dependent and 20 occasional smokers received 0.5 mg pramipexole using a double-blind, placebo-controlled crossover design. Motivation for cigarettes and consummatory nondrug rewards was measured using the DReaM-Choice task, in which participants earned, and later “consumed,” cigarettes, music, and chocolate. Demand for cigarettes was measured using the Cigarette Purchase Task (CPT). Self-reported craving, withdrawal, and drug effects were also recorded.

Results

Dependent smokers chose (p < .001) and button-pressed for (p < .001) cigarettes more, and chose chocolate less (p < .001), than occasional smokers. Pramipexole did not affect the number of choices for or amount of button-pressing for any reward including cigarettes, which was supported by a Bayesian analysis. The dependent smokers had greater demand for cigarettes than occasional smokers across all CPT outcomes (ps < .021), apart from elasticity. Pramipexole did not affect demand for cigarettes, and this was supported by Bayesian analyses. Pramipexole produced greater subjective “feel drug” and “dislike drug” effects than placebo.

Conclusions

Dependent and occasional cigarette smokers differed in their motivation for cigarettes but not for the nondrug rewards. Pramipexole did not acutely alter motivation for cigarettes. These findings question the role of dopamine D3 receptors in cigarette-seeking behavior in dependent and occasional smokers.

Implications

This study adds to the growing literature about cigarette versus nondrug reward processing in nicotine dependence and the role of dopamine in cigarette-seeking behavior. Our results suggest nicotine dependence is associated with a hypersensitivity to cigarette rewards but not a hyposensitivity to nondrug rewards. Furthermore, our results question the importance of dopamine D3 receptors in motivational processing of cigarettes in occasional and dependent smokers.

Testing the PPAR hypothesis of tobacco use disorder in humans: A randomized trial of the impact of gemfibrozil (a partial PPARα agonist) in smokers

Previous pre-clinical studies demonstrated a promising role of alpha-type peroxisome proliferator-activated receptors (PPARα) agonists in decreasing nicotine self-administration and nicotine-seeking behavior in animals. Our goal was to investigate the potential of gemfibrozil, a PPARα agonist, on reducing tobacco smoking in humans. Methods: This was a double-blind, placebo-controlled, crossover study evaluating the effects of gemfibrozil (1200 mg/day) on smoking in 27 treatment-seeking smokers. The study had two 2-week phases separated by a washout period of at least 1 week. In each phase and after 1 week on medication, participants underwent a lab session where cue reactivity and forced choice paradigms were conducted. Physiological responses and self-reported craving were monitored during the presentation of smoking and neutral cues. In addition, two types of cigarettes were used in the forced choice paradigms: the Nicotinized cigarettes (Nic) and the Denicotinized cigarettes (Denic). The goal of the forced choice was to calculate the percentage of choice of Nic cigarettes while taking gemfibrozil or placebo. The number of quit days was calculated during the two quit attempts weeks (one while taking gemfibrozil and one while taking placebo) of the study. Results: There were no significant differences between gemfibrozil and placebo groups in the percentage of choice of Nic cigarettes, the cue-reactivity (both physiological and subjective measures), or in the number of days of abstinence. Conclusions: Although preclinical studies with PPAR α agonists showed promising results, this preliminary study did not demonstrate positive effect of gemfibrozil on tobacco use and cessation indices.

Overcoming the "Valley of Death" in Medications Development for Alcohol Use Disorder

As the development of novel pharmacotherapies for alcohol use disorder (AUD) has been slow, the discovery and testing of more efficacious pharmacotherapies for AUD represent a high priority research area. In fact, the transition from preclinical to clinical testing of novel compounds has been termed the "valley of death" in medications development. One key obstacle consists of the lack of an articulated set of goals for each stage of medications development. Specifically, the knowledge outputs required to make the transition from safety testing, to early efficacy detection, to confirming clinical efficacy remain unclear, and this is despite a great deal of interest and substantial financial investment in developing novel therapeutics for AUD. This qualitative critical review seeks to draw parallels and lessons from the well-established stage model for behavioral therapies research with alcohol and other substance use disorders and to apply these insights into AUD pharmacotherapy development. We argue that human laboratory models and/or pilot randomized controlled trials should serve as intermediaries in the transition from preclinical studies to large, and costly, randomized controlled efficacy trials. The relative strengths and weaknesses of pilot clinical trials versus human laboratory studies for bridging the "valley of death" are discussed and explored via a Monte Carlo data simulation study. Multiple permutations of suitable research designs informed by the behavioral therapies development model are discussed with the overall goal of promoting consilience and maximizing efficiency across all phases of clinical testing of novel AUD pharmacotherapies.

Leveraging Genomic Data in Smoking Cessation Trials in the Era of Precision Medicine: Why and How

Implications

This article outlines a framework for the consistent integration of biological data/samples into smoking cessation pharmacotherapy trials, aligned with the objectives of the recently unveiled Precision Medicine Initiative. Our goal is to encourage and provide support for treatment researchers to consider biosample collection and genotyping their existing samples as well as integrating genetic analyses into their study design in order to realize precision medicine in treatment of nicotine dependence.

Stress-related increases in risk taking and attentional failures predict earlier relapse to smoking in young adults: A pilot investigation

Substantial evidence links greater impulsivity and stress exposure to poorer smoking cessation outcomes. Results from adolescents also indicate that stress-related change in risk taking can impede cessation attempts. We investigated the effects of stress-related change in impulsivity, risk taking, attention and nicotine withdrawal, and craving in young adult smokers on time to smoking relapse in a relapse analogue paradigm. Twenty-six young adult smokers (50% women; mean age: 20.9 ± 1.8) were exposed to a stress imagery session followed by a contingency management-based relapse analogue paradigm. Participants smoked at least 5 cigarettes daily, with a mean baseline carbon monoxide (CO) level of 13.7 (± 5.1) ppm. Repeated measures analysis of variance (ANOVA) and paired t tests examined stress induction validity and Cox regressions of proportional hazards examined the effects of stress-related changes in nicotine withdrawal, nicotine craving, attention, impulsivity, and risk taking on time to relapse. While stress-related change in impulsivity, nicotine craving and withdrawal did not predict time to relapse (all ps > .10), greater stress-related increases in reaction time (RT) variability (p = .02) were predictive of shorter time to relapse, with trend-level findings for inattention and risk taking. Furthermore, changes in stress-related risk taking affected outcome in women more than in men, with a significant relationship between stress-related change in risk taking only in women (p = .026). Smoking cessation attempts in young adults may be adversely impacted by stress-related increases in risk taking and attentional disruption. Clinicians working with young adults attempting cessation may need to target these stress-related impairments by fostering more adaptive coping and resilience.

How can we Improve on Modeling Nicotine Addiction to Develop Better Smoking Cessation Treatments?

Clinically effective smoking cessation treatments are few in number, mainly varenicline, bupropion, and nicotine replacement therapy being prescribed by health organizations. Of the many compounds tested for smoking cessation, a good proportion fail in human trials despite positive findings in rodents. This chapter aims to cover the uses and some pit falls of current methodologies employed to discover clinical treatments in the laboratory. Complicating factors include the complex nature of genetics in tobacco smoking and the comorbidity associated with other psychiatric disorders, which has not been addressed fully in the rodent laboratory. This chapter reviews the evidence from intravenous nicotine self-administration studies and proposes modifications on how we can improve the validity of the animal models by incorporating clinically relevant factors considered to be critical in tobacco smoking. For example, choice procedures that incorporate alternative reinforcers, use of reinstatement models, and second-order schedules of reinforcement are proposed to have better scientific validity that may lead to better clinical outcomes. Furthermore, improved experimental methods will also improve our chances of discovering effective treatments that ultimately may mitigate the effects of tobacco smoking with regard to health worldwide.

Does Extended Pre Quit Bupropion Aid in Extinguishing Smoking Behavior?

INTRODUCTION

Understanding the mechanisms by which bupropion promotes smoking cessation may lead to more effective treatment. To the extent that reduced smoking reinforcement is one such mechanism, a longer duration of pre quit bupropion treatment should promote extinction of smoking behavior. We evaluated whether 4 weeks of pre quit bupropion (extended run-in) results in greater pre quit reductions in smoking rate and cotinine and, secondarily, greater short-term abstinence, than standard 1 week of pre quit bupropion (standard run-in).

METHODS

Adult smokers (n = 95; 48 females) were randomized to a standard run-in group (n = 48; 3-week placebo, then 1-week bupropion pre quit) or an extended run-in group (4-week pre quit bupropion; n = 47). Both groups received group behavioral counseling and 7 weeks of post quit bupropion. Smoking rate (and craving, withdrawal, and subjective effects) was collected daily during the pre quit period; biochemical data (cotinine and carbon monoxide) were collected at study visits.

RESULTS

During the pre quit period, the extended run-in group exhibited a greater decrease in smoking rate, compared to the standard run-in group, interaction p = .03. Cigarette craving and salivary cotinine followed a similar pattern, though the latter was evident only among women. Biochemically verified 4-week continuous abstinence rates were higher in the extended run-in group (53%) than the standard run-in group (31%), p = .033.

CONCLUSIONS

The extended use of bupropion prior to a quit attempt reduces smoking behavior during the pre quit period and improved short-term abstinence rates. The data are consistent with an extinction-of-reinforcement model and support further investigation of extended run-in bupropion therapy for smoking cessation.

The Nicotine Metabolite Ratio is Associated With Early Smoking Abstinence Even After Controlling for Factors That Influence the Nicotine Metabolite Ratio

INTRODUCTION

The decrease in smoking rates in North America has plateaued, underscoring the need for new approaches to treat nicotine dependence. Inter-individual differences in smoking behavior result, in part, from variation in the rate of CYP2A6-mediated nicotine metabolism. A phenotypic measure of CYP2A6 activity is the nicotine metabolite ratio (NMR), the ratio of 3'hydroxycotinine/cotinine. The NMR is associated with smoking cessation. However, the NMR is also associated with genetic (eg, CYP2A6 genotype) and other (eg, sex and ethnicity) factors. Here we aimed to determine if previously identified non-CYP2A6 sources of variation in the NMR mitigated the association between the NMR and short-term abstinence.

METHODS

The NMR was determined from blood samples collected at intake from daily smokers aged 18-65. Biochemically-verified point prevalence abstinence (exhaled carbon monoxide level ≤ 8 ppm) was measured at 1 week following the target quit date in participants from a smoking cessation clinical trial (NCT01314001). Analyses were restricted to N = 462 blacks and N = 693 whites in the intent-to-treat sample.

RESULTS

Lower NMR (<0.31) was associated with a higher likelihood of 1-week abstinence (OR = 1.43; 95% CI = 1.12, 1.84). NMR was associated with abstinence even after controlling for treatment arm (nicotine patch or varenicline) and factors previously associated with NMR variation including sex, ethnicity, estrogen-containing hormonal therapy, body mass index, alcohol, and cigarette consumption.

CONCLUSIONS

NMR was associated with 1-week smoking abstinence; NMR may be a useful addition to medication screening approaches evaluating treatments for nicotine dependence.

Internet-based group contingency management to promote smoking abstinence

Internet-based group contingencies have been shown to promote brief periods of abstinence from cigarette smoking. Under a group contingency, small teams of smokers must collectively meet abstinence goals to receive monetary consequences. The present study investigated 2 arrangements, 1 in which all team members had to meet group treatment goals to receive monetary consequences (full group), and 1 in which team members had to meet some group goals and some individual goals to receive these consequences (mixed group). Mo̅tiv8 Systems, an Internet-based remote monitoring platform, was used to collect video-recorded breath carbon monoxide (CO) samples. All team members could communicate with each other via an online discussion forum. During baseline conditions, only 3.3% of CO samples were negative for smoking, which suggests that self-monitoring and access to the online discussion forum were insufficient to initiate abstinence. When the group contingencies were instituted 41.3% of CO samples were negative. There were no statistically significant differences between the 2 arrangements in the percentage of negative CO samples or point prevalence at the end of treatment or at the 3-month follow-up. Participants posted an average of 25 comments on the discussion forum, most of which were rated as positive by independent observers. The mean cost of vouchers per participant was lower in the full group ($33) relative to the mixed group ($190). The present results replicate and extend previous findings on group contingencies to promote abstinence and social support.

Effects of experimental negative affect manipulations on ad libitum smoking: a meta-analysis

AIMS

To quantify the effect of negative affect (NA), when manipulated experimentally, upon smoking as measured within laboratory paradigms. Quantitative meta-analyses tested the effects of NA versus neutral conditions on (1) latency to smoke and (2) number of puffs taken.

METHODS

Twelve experimental studies tested the influence of NA induction, relative to a neutral control condition (n = 1190; range = 24-235). Those providing relevant data contributed to separate random-effects meta-analyses to examine the effects of NA on two primary smoking measures: (1) latency to smoke (nine studies) and (2) number of puffs taken during ad libitum smoking (11 studies). Hedge's g was calculated for all studies through the use of post-NA cue responses relative to post-neutral cue responses. This effect size estimate is similar to Cohen's d, but corrects for small sample size bias.

RESULTS

NA reliably decreased latency to smoke (g = -0.14; CI = -0.23 to -0.04; P = 0.007) and increased number of puffs taken (g = 0.14; CI = 0.02 to 0.25; P = 0.02). There was considerable variability across studies for both outcomes (I(2)  = 51 and 65% for latency and consumption, respectively). Potential publication bias was indicated for both outcomes, and adjusted effect sizes were smaller and no longer statistically significant.

CONCLUSIONS

In experimental laboratory studies of smokers, negative affect appears to reduce latency to smoking and increase number of puffs taken, but this could be due to publication bias.

A laboratory-based evaluation of exercise plus contingency management for reducing cigarette smoking

BACKGROUND

Both contingency management (CM) and exercise have shown promise as smoking cessation treatments, but their combined effects have not been evaluated. The present study evaluated whether CM (in which motivational incentives are provided for abstinence) plus exercise reduced smoking more than either component alone.

METHOD

In a within-subjects design, 20 smokers were exposed to exercise plus CM, exercise plus CM-control (non-contingent incentives), inactivity plus CM, and inactivity plus CM-control.

RESULTS

CM increased latencies to smoke and decreased total puffs (Mdns = 39.6 min and .8 puffs, respectively) relative to CM-control (Mdns = 2.5 min and 12.8 puffs). Exercise decreased craving relative to baseline for craving based on both the pleasurable consequences of smoking (D=-10.7 on a 100-point visual analog scale) and anticipated relief from withdrawal (D=-5.9), whereas inactivity increased both components of craving (Ds=7.6 and 3.5). Exercise had no effect on smoking or a measure of temporal discounting.

CONCLUSIONS

Although exercise decreased craving, it did not affect smoking behavior. Exercise plus CM was not more effective than CM alone.

Varenicline, low dose naltrexone, and their combination for heavy-drinking smokers: human laboratory findings

RATIONALE

Heavy-drinking smokers constitute a sizeable and hard-to-treat subgroup of smokers, for whom tailored smoking cessation therapies are not yet available.

OBJECTIVES

The present study used a double-blind, randomized, 2 × 2 medication design, testing varenicline alone (VAR; 1 mg twice daily), low dose naltrexone alone (L-NTX; 25 mg once daily), varenicline plus naltrexone, and placebo for effects on cigarette craving and subjective response to alcohol and cigarettes in a sample (n = 130) of heavy-drinking daily smokers (≥10 cigarettes/day).

METHODS

All participants were tested after a 9-day titration period designed to reach a steady state on the target medication. Testing was completed at 12 h of nicotine abstinence, after consuming a standard dose of alcohol (target breath alcohol concentration = 0.06 g/dl) and after smoking the first cigarette of the day.

RESULTS

The combination of VAR + L-NTX was superior to placebo, and at times superior to monotherapy, in attenuating cigarette craving, cigarette and alcohol "high," and in reducing ad-lib consumption of both cigarettes and alcohol during the 9-day medication titration period.

CONCLUSIONS

These preliminary findings indicate that clinical studies of the combination of VAR + L-NTX for heavy drinkers trying to quit smoking are warranted and may ultimately improve clinical care for this sizeable and treatment-resistant subgroup of smokers.

Improving efficiency of initial tests for efficacy in smoking cessation drug discovery

INTRODUCTION

One obstacle to rapid development of new smoking cessation medications is the inefficient early clinical evaluation of the efficacy of novel drugs, which inform us as to whether or not to proceed with the greater expense and time of more formal clinical trials. The vast majority of novel drugs fail to show efficacy for cessation only after substantial resources have been spent and, thus, are largely wasted.

AREAS COVERED

The author reviews the general limitations in the current typical procedures for initial tests of cessation efficacy in novel drugs. Small, randomized clinical trials often have good validity but may have practical limitations in achieving adequate statistical power to test novel versus placebo treatment conditions. Lab tests of acute drug effects on abstinence symptoms, during brief enforced cessation periods, are practical but have limited clinical predictive validity.

EXPERT OPINION

Initial efficacy testing may be more efficient if done using innovative crossover designs that evaluate brief 'practice' quit periods for both active and placebo treatments within the same smokers, recruiting those high in quit motivation. Because this approach would require far fewer subjects and a shorter duration of testing, results could be obtained more rapidly and inexpensively to indicate that a novel drug may, or may not, be sufficiently efficacious as to warrant the greater costs and time of formal randomized clinical trials.

Predictors of smoking lapse in a human laboratory paradigm

RATIONALE

During a smoking quit attempt, a single smoking lapse is highly predictive of future relapse. While several risk factors for a smoking lapse have been identified during clinical trials, a laboratory model of lapse was until recently unavailable and, therefore, it is unclear whether these characteristics also convey risk for lapse in a laboratory environment.

OBJECTIVES

The primary study goal was to examine whether real-world risk factors of lapse are also predictive of smoking behavior in a laboratory model of smoking lapse.

METHODS

After overnight abstinence, 77 smokers completed the McKee smoking lapse task, in which they were presented with the choice of smoking or delaying in exchange for monetary reinforcement. Primary outcome measures were the latency to initiate smoking behavior and the number of cigarettes smoked during the lapse. Several baseline measures of smoking behavior, mood, and individual traits were examined as predictive factors.

RESULTS

Craving to relieve the discomfort of withdrawal, withdrawal severity, and tension level were negatively predictive of latency to smoke. In contrast, average number of cigarettes smoked per day, withdrawal severity, level of nicotine dependence, craving for the positive effects of smoking, and craving to relieve the discomfort of withdrawal were positively predictive of number of cigarettes smoked.

CONCLUSIONS

The results suggest that real-world risk factors for smoking lapse are also predictive of smoking behavior in a laboratory model of lapse. Future studies using the McKee lapse task should account for between subject differences in the unique factors that independently predict each outcome measure.

Donepezil, an acetylcholinesterase inhibitor, attenuates nicotine self-administration and reinstatement of nicotine seeking in rats

Nicotine craving and cognitive impairments represent core symptoms of nicotine withdrawal and predict relapse in abstinent smokers. Current smoking cessation pharmacotherapies have limited efficacy in preventing relapse and maintaining abstinence during withdrawal. Donepezil is an acetylcholinesterase inhibitor that has been shown previously to improve cognition in healthy non-treatment-seeking smokers. However, there are no studies examining the effects of donepezil on nicotine self-administration and/or the reinstatement of nicotine-seeking behavior in rodents. The present experiments were designed to determine the effects of acute donepezil administration on nicotine taking and the reinstatement of nicotine-seeking behavior, an animal model of relapse in abstinent human smokers. Moreover, the effects of acute donepezil administration on sucrose self-administration and sucrose seeking were also investigated in order to determine whether donepezil's effects generalized to other reinforced behaviors. Acute donepezil administration (1.0 or 3.0 mg/kg, i.p.) attenuated nicotine, but not sucrose self-administration maintained on a fixed-ratio 5 schedule of reinforcement. Donepezil administration also dose-dependently attenuated the reinstatement of both nicotine- and sucrose-seeking behaviors. Commonly reported adverse effects of donepezil treatment in humans are nausea and vomiting. However, at doses required to attenuate nicotine self-administration in rodents, no effects of donepezil on nausea/malaise as measured by pica were observed. Collectively, these results indicate that increased extracellular acetylcholine levels are sufficient to attenuate nicotine taking and seeking in rats and that these effects are not due to adverse malaise symptoms such as nausea.

Effects of exercise on craving and cigarette smoking in the human laboratory

Exercise is increasingly being pursued as a treatment to reduce cigarette smoking. The efficacy of clinical, exercise-based cessation interventions may be enhanced by conducting laboratory studies to determine maximally effective conditions for reducing smoking, and the mechanisms through which the effects on smoking are achieved. The main purpose of this study was to assess whether the effects of exercise on two components of craving (anticipated reward from smoking, anticipated relief from withdrawal) mediated the relationship between exercise and delay (in min) to ad libitum smoking. Experiment 1 (N=21) assessed the effects of exercise intensity (inactivity, low, moderate) on craving components up to 60 min post-exercise. Because moderate-intensity exercise most effectively reduced craving on the reward component, all participants exercised at a moderate intensity in Experiment 2. Using an ABAB within-subjects design, Experiment 2 (N=20) evaluated whether the effects of moderate-intensity exercise on reward and relief components of craving mediated the relationship between exercise and participants' delays (in min) to ad libitum smoking. Delays were significantly longer after exercise (M=21 min) versus inactivity (M=4 min), and the effects of exercise on delay were mediated through the reward component of craving. Future research should continue to explore the mechanisms through which exercise influences behavioral indices of smoking in the human laboratory. Additionally, given the benefits uniquely afforded by exercise-based cessation interventions (e.g., improving mood and other health outcomes), implementing these interventions in clinical settings may contribute substantially to improving public health.

Optimizing treatments for nicotine dependence by increasing cognitive performance during withdrawal

INTRODUCTION

Current FDA-approved smoking cessation pharmacotherapies have limited efficacy and are associated with high rates of relapse. Therefore, there is a clear need to develop novel antismoking medications. Nicotine withdrawal is associated with cognitive impairments that predict smoking relapse. It has been proposed that these cognitive deficits are a hallmark of nicotine withdrawal that could be targeted in order to prevent smoking relapse. Thus, pharmacotherapies that increase cognitive performance during nicotine withdrawal may represent potential smoking cessation agents.

AREAS COVERED

The authors review the clinical literature demonstrating that nicotine withdrawal is associated with deficits in working memory, attention and response inhibition. They then briefly summarize different classes of compounds and strategies to increase cognitive performance during nicotine withdrawal. Particular emphasis has been placed on translational research in order to highlight areas for which there is strong rationale for pilot clinical trials of potential smoking cessation medications.

EXPERT OPINION

There is emerging evidence that supports deficits in cognitive function as a plausible nicotine withdrawal phenotype. The authors furthermore believe that the translational paradigms presented here may represent efficient and valid means for the evaluation of cognitive-enhancing medications as possible treatments for nicotine dependence.

An efficient early phase 2 procedure to screen medications for efficacy in smoking cessation

RATIONALE

Initial screening of new medications for potential efficacy (i.e., Food and Drug Administration (FDA) early phase 2), such as in aiding smoking cessation, should be efficient in identifying which drugs do, or do not, warrant more extensive (and expensive) clinical testing.

OBJECTIVES

This focused review outlines our research on development, evaluation, and validation of an efficient crossover procedure for sensitivity in detecting medication efficacy for smoking cessation. First-line FDA-approved medications of nicotine patch, varenicline, and bupropion were tested as model drugs, in three separate placebo-controlled studies. We also tested specificity of our procedure in identifying a drug that lacks efficacy, using modafinil.

RESULTS

This crossover procedure showed sensitivity (increased days of abstinence) during week-long "practice" quit attempts with each of the active cessation medications (positive controls) versus placebo, but not with modafinil (negative control) versus placebo, as hypothesized. Sensitivity to medication efficacy signal was observed only in smokers high in intrinsic quit motivation (i.e., already preparing to quit soon) and not smokers low in intrinsic quit motivation, even if monetarily reinforced for abstinence (i.e., given extrinsic motivation).

CONCLUSIONS

A crossover procedure requiring less time and fewer subjects than formal trials may provide an efficient strategy for a go/no-go decision whether to advance to subsequent phase 2 randomized clinical trials with a novel drug. Future research is needed to replicate our results and evaluate this procedure with novel compounds, identify factors that may limit its utility, and evaluate its applicability to testing efficacy of compounds for treating other forms of addiction.

Sensitivity and specificity of a procedure for early human screening of novel smoking cessation medications

BACKGROUND AND AIM

It is important to find economical methods in early Phase 2 studies to screen drugs potentially useful to aid smoking cessation. A method has been developed that detects efficacy of varenicline and nicotine patch. This study aimed to evaluate whether the method would detect the efficacy of bupropion and identify correctly the lack of efficacy of modafinil.

DESIGN

Using a within-subject double cross-over design, smokers attempted to quit during each treatment, with bupropion (150 mg b.i.d.), modafinil [100 mg twice daily (b.i.d.)] or placebo (double-blind, counterbalanced order). In each of three medication periods, all smoked with no drug on week 1 (baseline or washout), began dose run-up on week 2, and tried to quit every day during week 3.

SETTING

A university research center in the United States.

PARTICIPANTS

Forty-five adult smokers high in quit interest.

MEASUREMENTS

Abstinence was verified daily each quit week by self-report of no smoking over the prior 24 hours and carbon monoxide (CO) < 5 parts per million.

FINDINGS

Compared with placebo, bupropion did (F(1,44)  = 6.98, P = 0.01), but modafinil did not (F(1,44)  = 0.29, P = 0.60), increase the number of abstinent days. Also, bupropion (versus placebo) significantly increased the number of those able to maintain continuous abstinence on all 5 days throughout the quit week (11 versus four), Z = 2.11, P < 0.05, while modafinil did not (six).

CONCLUSIONS

Assessing days abstinent during 1 week of use of medication versus placebo in a cross-over design could be a useful early Phase 2 study design for discriminating between medications useful versus not useful in aiding smoking cessation.

The first 7 days of a quit attempt predicts relapse: validation of a measure for screening medications for nicotine dependence

OBJECTIVES

There is a critical need for the development of novel treatments for nicotine dependence. Because the majority of smokers who make a quit attempt fail within 7 days, medication screening procedures that focus on this early cessation period may provide an indicator of treatment efficacy. To establish the clinical validity of this paradigm, it is critical to demonstrate the association of early abstinence with longer-term abstinence. We tested the number of days of abstinence during the first week after the target quit date (TQD) as a predictor of point prevalence abstinence in 3 independent pharmacotherapy trials for nicotine dependence.

METHODS

This was a secondary data analysis of 3 randomized clinical trials: a placebo-controlled trial of transdermal nicotine (N = 545); an open-label nicotine replacement therapy (patch vs spray) trial (N = 566); and a bupropion placebo-controlled trial (N = 538). In separate logistic regression models, the maximum number of consecutive days of abstinence during the first week after the TQD was used to predict biochemically verified 7-day point prevalence abstinence at the end of treatment (EOT) and 6 months post-TQD.

RESULTS

Across the 3 trials, the number of days of abstinence significantly predicted abstinence at EOT and 6 months (odds ratios > 1.4; Ps < 0.0001). Likewise, not having any lapse during the first week predicted abstinence at EOT and 6 months (odds ratios > 4.7; Ps < 0.0001).

CONCLUSIONS

The first week of abstinence was highly predictive of EOT and long-term abstinence. Medication screening procedures that focus on this early abstinence period (ie, 6 or 7 days of consecutive abstinence) represent a valid tool for assessing the presence of a signal for medication efficacy.

The effects of varenicline on stress-induced and cue-induced craving for cigarettes

BACKGROUND

Varenicline is a partial agonist of the α4β2 nicotinic acetylcholine receptor approved by the FDA for the treatment of nicotine dependence. While the clinical efficacy of varenicline for smoking cessation is well-supported, its biobehavioral mechanisms of action remain poorly understood. This randomized, crossover, placebo-controlled, human laboratory study combines guided imagery stress exposure with in vivo presentation of cigarette cues to test the effects of varenicline on stress-induced and cue-induced craving for cigarettes.

METHOD

A total of 40 (13 females) daily smokers (≥10 cigarettes per day) completed a guided imagery exposure (stress and neutral) followed by the presentation of cigarette cues at the target dose of varenicline (1mg twice per day) and on matched placebo.

RESULTS

Multilevel regression models revealed a significant main effect of varenicline (p<.01) such that it reduced cigarette craving across the experimental paradigm, compared to placebo. There was also a significant medication×stress×trial interaction indicating that varenicline attenuated cue induced craving following neutral imagery but not when cues were preceded by stress induction (i.e., stress+cues).

CONCLUSIONS

These results elucidate the biobehavioral effects of varenicline for nicotine dependence and suggest that varenicline-induced amelioration of cigarette craving is unique to tonic craving and cue-induced craving following neutral imagery but does not extend to the combination of stress plus cues.

Investigating group contingencies to promote brief abstinence from cigarette smoking

In contingency management (CM), monetary incentives are contingent on evidence of drug abstinence. Typically, incentives (e.g., "vouchers" exchangeable for goods or services) are contingent on individual performance. We programmed vouchers contingent on group performance to investigate whether these contingencies would promote brief abstinence from cigarette smoking. Thirty-two participants were divided into small teams (n = 3 per team). During three 5-day within-subject experimental conditions, participants submitted video recordings of breath carbon monoxide (CO) measures twice daily via Motiv8 Systems, an Internet-based remote monitoring application. During the interdependent contingency condition, participants earned vouchers each time they and their teammates submitted breath CO samples indicative of abstinence (i.e., negative samples). During the independent contingency condition, participants earned vouchers each time they submitted negative samples, regardless of their teammates' performance. During the no vouchers condition, no monetary incentives were contingent on abstinence. In addition, half of the participants (n = 16) could communicate with their teammates through an online peer support forum. Although forum access did not appear to promote smoking abstinence, monetary incentives did promote brief abstinence. Significantly more negative samples were submitted when vouchers were contingent on individual performance (56%) or team performance (53%) relative to when no vouchers were available (35%; F = 6.9, p = .002). The results show that interdependent contingencies can promote brief abstinence from cigarette smoking. Moreover, the results suggest that these contingencies may help lower treatment costs and promote social support.

A human laboratory pilot study with baclofen in alcoholic individuals

Preclinical and clinical studies show that the GABA(B) receptor agonist baclofen may represent a pharmacotherapy for alcohol dependence (AD). However, the mechanisms by which baclofen affects drinking are not well characterized; thus this pilot study investigated possible baclofen's biobehavioral mechanisms. The design was a double-blind controlled randomized human laboratory pilot study. Fourteen non-treatment seeking alcohol-dependent heavy drinking subjects received either baclofen 10mg t.i.d. or an active placebo (cyproheptadine 2mg t.i.d., to control for sedation) for a 7-day period. At day 8, participants performed an alcohol cue-reactivity (CR) followed by an alcohol self-administration (ASA). Additionally, we explored possible moderators that might guide future larger studies, i.e. anxiety, family history and onset of alcoholism, and D4 dopamine receptor (DRD4) and 5-HTTLPR polymorphisms. The main results were a significant effect of baclofen for increasing stimulation (p=.001) and sedation (p<.01). Furthermore, when drinking during the ASA and the 2 days before was analyzed as a composite variable, there was a significant effect of baclofen to reduce alcohol consumption (p<.01). As for the exploratory analyses, baclofen's effects to increase alcohol sedation and to reduce alcohol consumption were limited to those individuals with DRD4 ≥7 repeats (DRD4L). Yet, baclofen's effects on alcohol consumption were also moderated by 5-HTTLPR LL genotype. In conclusion, baclofen's ability to reduce alcohol drinking may be related to its effects on the biphasic effects of alcohol, but larger studies are needed to confirm these preliminary findings.

Effects of divalproex on smoking cue reactivity and cessation outcomes among smokers achieving initial abstinence

Divalproex, a GABA agonist, may be a useful agent in the treatment of tobacco dependence. Cue reactivity assessment paradigms are ideally suited to explore basic mechanisms underlying the pharmacological effects of medications that purport to have efficacy for smoking cessation. Our primary goal in the current study was to examine the effects of divalproex on in-treatment reactivity to smoking-relevant and affective cues, and to determine if these reactions were predictive of posttreatment smoking behavior. There were 120 nicotine dependent smokers enrolled in an 8-week double-blind clinical trial and randomly assigned to either divalproex or placebo conditions. Of these, 72 smokers (60% female) who achieved a minimal level of abstinence underwent an in-treatment cue reactivity assessment. Contrary to expectations, divalproex was associated with greater craving and arousal during smoking cue presentation. Divalproex also inhibited cardiovascular response to pleasant cues. Although no significant differences in cessation-related outcomes between divalproex- and placebo-treated participants were observed, cue-elicited craving to smoke predicted end-of-treatment and posttreatment smoking rates. These findings suggest that in-treatment cue reactivity assessment may proactively and dynamically inform ongoing treatment as well as provide a tool for screening potential medications for smoking cessation.

Dependence and withdrawal-induced craving predict abstinence in an incentive-based model of smoking relapse

INTRODUCTION

Understanding factors that render some individuals more vulnerable to smoking relapse during the early stages of a quit attempt is critical to tailoring treatment efforts. Development of laboratory models of relapse can provide a framework for identifying underlying mechanisms that may contribute to vulnerability. Here, we explored predictors of abstinence in a novel incentive-based model of relapse.

METHODS

Fifty-six nontreatment seeking daily smokers completed several nicotine dependence measures prior to participating in a 1-week abstinence incentive test. During the abstinence procedure, participants earned monetary reinforcement for each biochemically verified day of abstinence according to a descending schedule of reinforcement.

RESULTS

Compliance with the procedure was excellent. All but 3 participants were able to initiate abstinence; nearly 70% lapsed as incentives were reduced. Scores on the Fagerström Test for Nicotine Dependence (FTND), number of cigarettes smoked per day, and self-reported craving on the first day of abstinence each independently predicted time to lapse. The single item of time to first cigarette in the morning on the FTND significantly predicted time to lapse, even when controlling for other significant predictors just listed. The Nicotine Dependence Syndrome Scale (NDSS) and Wisconsin Inventory of Smoking Dependence Motives did not predict lapse, but the NDSS did predict reinitiation of abstinence among those experiencing an initial lapse.

CONCLUSIONS

These findings partially replicate those of previous full-scale clinical trials and support the feasibility and validity of an incentive-based model of relapse. The time-limited and laboratory-based nature of this model has the potential to further investigations of underlying mechanisms contributing to relapse.

Blunted vagal reactivity predicts stress-precipitated tobacco smoking

RATIONALE

Long-term smoking can lead to changes in autonomic function, including decreased vagal tone and altered stress responses. One index of the inability to adapt to stress may be blunted vagal reactivity. Stress is a primary mechanism involved in relapse to smoking, but mechanisms leading to stress-precipitated relapse are not well understood.

OBJECTIVES

Using an experimental paradigm of stress-precipitated smoking behavior, we examined whether autonomic reactivity mediates the relationship between stress and smoking. High-frequency heart rate variability (HF-HRV), a putative measure of vagal tone, and the ratio of low-to-high frequency HRV (LF/HF), a measure of sympathovagal balance, were assessed.

METHODS

Using a within-subjects design, 32 nicotine-dependent, 15-h abstinent smokers (a subgroup from McKee et al. (J Psychopharmacol 25(4):490-502, 2011)) were exposed to individualized script-driven imagery of stressful and relaxing scenarios and assessed on the ability to resist smoking and subsequent ad-lib smoking. HRV was monitored throughout each laboratory session (maximum 60 min following imagery).

RESULTS

As expected, stress and ad-lib smoking additively decreased HF-HRV and increased LF/HF. Blunted stress-induced HF-HRV responses reflecting decreased vagal reactivity were associated with less time to initiate smoking and increased craving relief and reinforcement from smoking. These relationships were specific to HF-HRV following stress as neither baseline HF-HRV, HF-HRV following relaxing imagery, or LF/HF predicted smoking behavior.

CONCLUSIONS

The current findings are the first to experimentally demonstrate that stress-precipitated decreased vagal reactivity predicts the ability to resist smoking. Findings suggest that strategies that normalize vagal reactivity in early abstinent smokers may lead to improved smoking cessation outcomes.

Why two smoking cessation agents work better than one: role of craving suppression

OBJECTIVE

This research examined why smokers receiving combination medication for smoking cessation are more likely to quit smoking than are those who receive either single agent (monotherapy) or placebo.

METHOD

Data were collected from 1,504 current smokers (58.2% women, 83.9% White; mean age = 44.67 years, SD = 11.08) participating in a cessation clinical trial who were randomized to 1 of 6 cessation pharmacotherapy conditions (placebo, nicotine patch, nicotine lozenge, bupropion, nicotine patch + nicotine lozenge, and bupropion + nicotine lozenge). Participants completed ecological momentary assessments 4 times a day, concerning 5 hypothesized mediators (negative affect, positive affect, craving, smoking expectations, and withdrawal) of pharmacotherapy effects. Medications were provided for 8-12 weeks post-quit along with 6 individual counseling sessions. Mediational paths were estimated via a novel Bayesian approach with estimation of multiple mediator models.

RESULTS

Biochemically confirmed 8-week abstinence was the outcome variable, with the monotherapy and combination pharmacotherapy composites producing 45% (n = 689) and 54% (n = 478) abstinence rates, respectively. The univariate models suggested that the combination treatments produced higher abstinence rates than the monotherapies because of greater suppression of withdrawal, craving, and smoking expectations. However, multiple mediator models showed that the suppression of craving on the quit day produced the strongest mediational effects and could account for the mediational effects of other tested variables.

CONCLUSION

Suppression of craving on the quit day significantly mediates the clinical effects of monotherapies and combination smoking pharmacotherapies, and the higher abstinence rates for combination therapy versus monotherapies appear primarily due to greater craving suppression.

Nicotine therapy sampling to induce quit attempts among smokers unmotivated to quit: a randomized clinical trial

BACKGROUND

Rates of smoking cessation have not changed in a decade, accentuating the need for novel approaches to prompt quit attempts.

METHODS

Within a nationwide randomized clinical trial (N = 849) to induce further quit attempts and cessation, smokers currently unmotivated to quit were randomized to a practice quit attempt (PQA) alone or to nicotine replacement therapy (hereafter referred to as nicotine therapy), sampling within the context of a PQA. Following a 6-week intervention period, participants were followed up for 6 months to assess outcomes. The PQA intervention was designed to increase motivation, confidence, and coping skills. The combination of a PQA plus nicotine therapy sampling added samples of nicotine lozenges to enhance attitudes toward pharmacotherapy and to promote the use of additional cessation resources. Primary outcomes included the incidence of any ever occurring self-defined quit attempt and 24-hour quit attempt. Secondary measures included 7-day point prevalence abstinence at any time during the study (ie, floating abstinence) and at the final follow-up assessment.

RESULTS

Compared with PQA intervention, nicotine therapy sampling was associated with a significantly higher incidence of any quit attempt (49% vs 40%; relative risk [RR], 1.2; 95% CI, 1.1-1.4) and any 24-hour quit attempt (43% vs 34%; 1.3; 1.1-1.5). Nicotine therapy sampling was marginally more likely to promote floating abstinence (19% vs 15%; RR, 1.3; 95% CI, 1.0-1.7); 6-month point prevalence abstinence rates were no different between groups (16% vs 14%; 1.2; 0.9-1.6).

CONCLUSION

Nicotine therapy sampling during a PQA represents a novel strategy to motivate smokers to make a quit attempt.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00706979.

Lapse-induced surges in craving influence relapse in adult smokers: an experimental investigation

OBJECTIVES

Nearly all smokers who lapse experience a full-blown relapse, but the mediating mechanisms that contribute to this relationship are not well understood. A better understanding of these mechanisms would help to advance more effective relapse prevention treatments for smokers. The purpose of this study is to experimentally evaluate the effects of a programmed smoking lapse on smoking relapse and the effects of postlapse changes in craving on relapse.

METHOD

Adult smokers (n = 63) who quit smoking with a brief cognitive-behavioral intervention and self-help materials were randomly assigned to one of two experimental conditions after 48 h of abstinence: No lapse (a no-smoking control/30-min waiting period) or lapse (smoking two cigarettes of their favored brand during a 30-min period). All participants were then followed daily for 14 days. Craving and biochemically verified self-reported abstinence were assessed on each follow-up day. Time (days) to relapse (7 consecutive days of smoking) was the main dependent measure.

RESULTS

Results of Cox regression analysis revealed that participants in the lapse condition relapsed more quickly than participants in the no-lapse condition (hazard ratio [HR] = 2.12, 95% confidence interval [CI] = [1.03, 4.35]). These effects were attributable, in part, to episodic increases in craving among participants in the lapse condition only (HR = 12.42, 95% CI = [2.00, 77.1]).

CONCLUSIONS

Previously abstinent smokers who lapse are at risk for increased cigarette cravings and consequently, full-blown relapse. These results have implications for both cognitive-behavioral treatments for relapse prevention and for medications designed to help smokers manage cravings.

A randomised placebo-controlled trial of oral hydrocortisone for treating tobacco withdrawal symptoms

RATIONALE

Many smokers experience a decline in cortisol to sub-normal levels during the first days of smoking cessation. A greater decline in cortisol is associated with more intense cigarette withdrawal symptoms, urge to smoke and relapse to smoking. Findings from an uncontrolled study suggest that glucocorticoids could ameliorate cigarette withdrawal.

OBJECTIVES

We investigated whether taking oral hydrocortisone would reduce withdrawal symptoms and the desire to smoke on the first day of temporary smoking abstinence compared with placebo.

METHODS

Using a double-blind within-subject randomised crossover design, 48 smokers took a single dose of 40 mg hydrocortisone, 20 mg hydrocortisone or placebo following overnight smoking abstinence. Abstinence was maintained through the afternoon, and withdrawal symptoms and the desire to smoke were rated across the morning. Salivary cortisol was assessed in the afternoon prior to abstinence (baseline) and while abstinent after each treatment.

RESULTS

There was a significant dose-response relation between dose of hydrocortisone and reduction in depression and anxiety ratings while abstinent, but there were no other statistically significant associations with dose. Overall, the decline in cortisol following smoking cessation (placebo only) was not significant. Cortisol level on the afternoon of smoking abstinence was not significantly associated with symptom ratings.

CONCLUSIONS

Supplements of hydrocortisone do not reduce the desire to smoke but may ameliorate withdrawal-related depression and anxiety, although the clinical benefit is slight.

Stress decreases the ability to resist smoking and potentiates smoking intensity and reward

We have developed a novel human laboratory model to examine two primary aspects of stress-precipitated tobacco relapse: (1) Does stress reduce the ability to resist the first cigarette? (2) Once the first cigarette is initiated, does stress facilitate subsequent smoking? Using a within-subject design, daily smokers (n = 37) who were nicotine deprived overnight received a personalized imagery induction (stress or neutral) on two separate days, and then had the option of initiating a tobacco self-administration session or delaying initiation for up to 50 min in exchange for three levels of monetary reinforcement. Subsequently, the tobacco self-administration session entailed a 1-hour period in which subjects could choose to smoke using a smoking topography system. Following the stress induction, subjects were less able to resist smoking, smoked more intensely (increased puffs, shorter inter-puff interval, and greater peak puff velocity), and perceived greater satisfaction and reward from smoking. Stress significantly increased hypothalamus-pituitary-adrenal (HPA) axis reactivity, tobacco craving, negative emotion, and physiologic reactivity relative to the neutral condition. In addition, increased cortisol, ACTH, and tobacco craving were associated with reduced ability to resist smoking following stress. These findings have implications for understanding the impact of stress on smoking relapse and model development to assess smoking lapse behavior.

New methods for tobacco dependence treatment research

INTRODUCTION

Despite advances in tobacco dependence treatment in the past two decades, progress has been inconsistent and slow. This paper reviews pervasive methodological issues that may contribute to the lack of timely progress in tobacco treatment science including the lack of a dynamic model or framework of the cessation process, inefficient study designs, and the use of distal outcome measures that poorly index treatment effects. The authors then present a phase-based cessation framework that partitions the cessation process into four discrete phases based on current theories of cessation and empirical data. These phases include: (1) Motivation, (2) Precessation, (3) Cessation, and (4) Maintenance.

DISCUSSION

Within this framework, it is possible to identify phase-specific challenges that a smoker would encounter while quitting smoking, intervention components that would address these phase-specific challenges, mechanisms via which such interventions would exert their effects, and optimal outcome measures linked to these phase-specific interventions. Investigation of phase-based interventions can be accelerated by using efficient study designs that would permit more timely development of an optimal smoking cessation treatment package.

Nicotine reduction revisited: science and future directions

Regulation of nicotine levels in cigarettes and other tobacco products is now possible with the passage of the Family Smoking Prevention and Tobacco Control Act (FSPTCA) in 2009, giving the US Food and Drug Administration (FDA) authority to regulate tobacco products, and with Articles 9-11 of the WHO Framework Convention on Tobacco Control. Both regulatory approaches allow establishing product standards for tobacco constituents, including nicotine. The FSPTCA does not allow nicotine levels to be decreased to zero, although the FDA has the authority to reduce nicotine yields to very low, presumably non-addicting levels. The proposal to reduce levels of nicotine to a level that is non-addicting was originally suggested in 1994. Reduction of nicotine in tobacco products could potentially have a profound impact on reducing tobacco-related morbidity and mortality. To examine this issue, two meetings were convened in the US with non-tobacco-industry scientists of varied disciplines, tobacco control policymakers and representatives of government agencies. This article provides an overview of the current science in the area of reduced nicotine content cigarettes and key conclusions and recommendations for research and policy that emerged from the deliberations of the meeting members.