Immediate Switching to Reduced Nicotine Cigarettes in a U.S.-Based Sample: The Impact on Cannabis Use and Related Variables at 20 Weeks.

INTRODUCTION: The FDA proposed rule-making to reduce nicotine in cigarettes to minimally addictive levels. Research suggests decreasing nicotine levels (i.e. very low nicotine content cigarettes [VLNCs]) produced greater quit attempts, reduced smoking, and reduced exposure to harmful constituents among smokers. The impact of long-term VLNC use among people who co-use cigarettes and cannabis on non-tobacco-specific toxicant and carcinogen exposure has not been investigated. AIMS AND METHODS: This study presents secondary analyses of a controlled clinical trial examining switching to VLNC (versus a normal nicotine cigarettes control group [NNCs]) between people who co-use cigarettes and cannabis (n = 174) versus smoked cigarettes (n = 555). Linear mixed-effects models compared changes in smoking behavior, and tobacco-specific (i.e. total nicotine equivalents [TNE], 4-[methylnitrosamino]-1-[3-pyridyl]-1-butanone [NNK; total NNAL]) and non-tobacco-specific (i.e. carbon monoxide (CO), 2-cyanoethylmercapturic acid [CEMA], phenanthrene tetraol [PheT]) toxicant and carcinogen exposure at week 20 (with random intercept for participants). Cannabis use was measured among co-use groups. RESULTS: CO was significantly lower only among the cigarette-only group assigned VLNCs (interaction: p = .015). Although both VLNC groups demonstrated decreased CEMA, greater decreases emerged among the cigarette-only group (interaction: p = .016). No significant interactions emerged for TNE, cigarettes per day (CPD), NNAL, and PheT (ps > .05); both VLNC groups decreased in TNE, CPD, and NNAL. Only the cigarette-only group assigned VLNCs demonstrated decreased PheT (p < .001). The VLNC co-use group showed increased cannabis use over time (p = .012; 0.5 more days per week by week 20). CONCLUSIONS: Those who co-use cannabis and cigarettes may still be at risk for greater exposure to non-tobacco-specific toxicants and carcinogens compared to those who only smoke cigarettes. IMPLICATIONS: The present study is the longest longitudinal, prospective comparison study of smoking behavior and exposure to harmful constituents among those who co-use cigarettes and cannabis versus cigarette-only after immediately switching to very low nicotine content cigarettes (VLNC). Those who co-use experienced similar reductions in CPD and tobacco-specific exposure, compared to those who only use cigarettes. However, co-use groups experienced smaller reductions in non-tobacco-specific toxicants and carcinogens compared to the cigarette-only group, potentially because of combustible cannabis use. Additionally, those who co-use and switched to VLNC may be susceptible to slight increases in cannabis use (approximately two more days per year).

Smoking abstinence and cessation-related outcomes one month after an immediate versus gradual reduction in nicotine content of cigarettes.

The United States Food and Drug Administration has the authority to reduce the nicotine content in cigarettes to minimal or non-addictive levels and could do so immediately or gradually over time. A large clinical trial compared the two approaches. This secondary analysis assesses abstinence and cessation-related outcomes one month after the trial concluded, when participants no longer had access to very low nicotine content (VLNC) research cigarettes. Smokers not interested in quitting (N = 1250) were recruited for the parent trial from 2014 to 2016 across 10 sites throughout the US and randomized to a 20-week study period during which they immediately switched to VLNC cigarettes, gradually transitioned to VLNC cigarettes with five monthly dose reductions, or smoked normal nicotine research cigarettes (control). At the one-month follow-up, both immediate and gradual reduction resulted in greater mean cigarette-free days (4.7 and 4.6 respectively) than the control group (3.2, both p < .05). Immediate reduction resulted in fewer mean cigarettes per day (CPD = 10.3) and lower Fagerström Test for Cigarette Dependence (FTCD = 3.7) than the gradual (CPD = 11.7, p = .001; FTCD = 3.8, p = .039) and control (CPD = 13.5, p < .001; FTCD = 4.0, p < .001) groups. Compared to controls, gradual reduction resulted in reduced CPD (p = .012) but not FTCD (p = .13). Differences in CO-verified 7-day point-prevalence abstinence were not significant. Findings demonstrate that switching to VLNC cigarettes resulted in reduced smoking and nicotine dependence severity that was sustained for at least a month after the VLNC trial period in smokers who were not interested in cessation. The greatest harm reduction endpoints were observed in those who immediately transitioned to VLNC cigarettes.

An Evaluation of Potential Unintended Consequences of a Nicotine Product Standard: A Focus on Drinking History and Outcomes.

INTRODUCTION: A nicotine product standard reducing the nicotine content in cigarettes could improve public health by reducing smoking. This study evaluated the potential unintended consequences of a reduced nicotine product standard by examining its effects on (1) smoking behaviors based on drinking history; (2) drinking behavior; and (3) daily associations between smoking and drinking. METHODS: Adults who smoke daily (n = 752) in the United States were randomly assigned to smoke very low nicotine content (VLNC) cigarettes versus normal nicotine content (NNC; control) cigarettes for 20 weeks. Linear mixed models determined if baseline drinking moderated the effects of VLNC versus NNC cigarettes on Week 20 smoking outcomes. Time-varying effect models estimated the daily association between smoking VLNC cigarettes and drinking outcomes. RESULTS: Higher baseline alcohol use (vs no use or lower use) was associated with a smaller effect of VLNC on Week 20 urinary total nicotine equivalents (ps < .05). No additional moderation was supported (ps > .05). In the subsample who drank (n = 415), in the VLNC versus NNC condition, daily alcohol use was significantly reduced from Weeks 17 to 20 and odds of binge drinking were significantly reduced from Weeks 9 to 17. By Week 7, in the VLNC cigarette condition (n = 272), smoking no longer predicted alcohol use but remained associated with binge drinking. CONCLUSIONS: We did not support negative unintended consequences of a nicotine product standard. Nicotine reduction in cigarettes generally affected smoking behavior for individuals who do not drink or drink light-to-moderate amounts in similar ways. Extended VLNC cigarette use may improve public health by reducing drinking behavior. IMPLICATIONS: There was no evidence that a VLNC product standard would result in unintended consequences based on drinking history or when considering alcohol outcomes. Specifically, we found that a very low nicotine standard in cigarettes generally reduces smoking outcomes for those who do not drink and those who drink light-to-moderate amounts. Furthermore, an added public health benefit of a very low nicotine standard for cigarettes could be a reduction in alcohol use and binge drinking over time. Finally, smoking VLNC cigarettes may result in a decoupling of the daily associations between smoking and drinking.

How Does Smoking and Nicotine Dependence Change After Onset of Vaping? A Retrospective Analysis of Dual Users.

INTRODUCTION: Although some smokers switch to exclusive use of electronic cigarettes (e-cigarettes), others become dual users of combustible cigarettes and e-cigarettes. Little is known about how the onset of vaping affects the use of and dependence on combustible cigarettes or total nicotine use and dependence, which may influence health-related and cessation outcomes. Using self-report data of current combustible and e-cigarette use and retrospective recall of pre-vaping smoking in a sample of dual users, the aims of this study were (1) to compare pre- and post-vaping number of cigarettes per day and combustible cigarette dependence; (2) to compare pre- and post-vaping total nicotine use frequency (number of vaping sessions and cigarettes smoked per day), and total nicotine dependence; and (3) to examine predictors of nicotine dependence. METHODS: We used baseline data from a smoking cessation trial with 2896 dual users. Nicotine use frequency and the Heaviness of Smoking Index were used as measures of nicotine use and dependence, respectively. RESULTS: Participants decreased cigarettes/day from pre- (M = 19.24, SD = 9.01) to post-vaping (M = 11.15, SD = 8.02, p < .0001) and combustible cigarette dependence declined from pre- (M = 3.55, SD = 1.51) to post-vaping (M = 2.11, SD = 1.60, p < .0001). Total daily nicotine use frequency increased after initiating vaping (M = 19.25, SD = 9.01 vs. M = 29.46, SD = 8.61; p < .0001), as did total nicotine dependence (M = 3.55, SD = 1.51 vs. M = 4.68, SD = 1.38; p < .0001). Hierarchical regression analyses indicated that variables associated with greater overall nicotine dependence included: younger age, lower education, more years smoking, higher pre-vaping nicotine dependence, using e-cigarettes more days per month, more puffs per vaping session, higher e-liquid nicotine concentration, and longer vaping history. CONCLUSIONS: Dual use leads to a reduction in the number of combustible cigarettes, but total nicotine use and dependence increases. IMPLICATIONS: In dual users, a reduction in smoking following onset of vaping may offer some harm reduction via reduction in cigarette intake. However, the increase in total nicotine use and dependence could affect the ability to quit either or both products.

Very Low Nicotine Content Cigarettes Disrupt the Feedback Loop of Affective States and Smoking Behavior.

INTRODUCTION: Smoking to reduce negative affect has been identified as a key motivational feature of tobacco use. Our recent work suggests that smoking very low nicotine content (VLNC) cigarettes reduces the relationship between negative affect and smoking behavior over a 6-week period. Here, we sought to extend our findings by evaluating whether a gradual or immediate approach to switching to VLNC cigarettes led to a differential reduction in the relationship between affect and smoking behavior over a longer (20-week) period. AIMS AND METHODS: Participants (n = 1250) were adult smokers from 10 US sites randomized to one of three groups: gradual nicotine reduction (15.5, 11.7, 5.2, 2.4, and 0.4 mg of nicotine per gram of tobacco [mg/g]), immediate nicotine reduction (0.4 mg/g), or standard nicotine content cigarettes (15.5 mg/g; control), for 20 weeks. We examined whether the relationship between affect-both negative and positive-and cigarettes per day differed as a function of reduction group. RESULTS: We found that both negative and positive affect were associated with cigarette consumption in the control group, but not in the gradual or immediate reduction groups across the 20 weeks of exposure. CONCLUSIONS: Our results extend previous findings that switching to VLNC cigarettes disrupts the relationship between affect and cigarette consumption by showing that either gradually or immediately reducing cigarette nicotine content achieves this disruption. These findings provide further evidence that switching to VLNC cigarettes reduces nicotine-related reinforcement of cigarette smoking. IMPLICATIONS: These findings support the notion that switching to very low nicotine content cigarettes reduces the association between affect and smoking behavior, and that either a gradual or immediate nicotine reduction approach achieves this reduction. This provides further evidence that switching to very low nicotine content cigarettes weakens reinforcement mechanisms associated with nicotine dependence.

Behavioral and Subjective Effects of Reducing Nicotine in Cigarettes: A Cessation Commentary.

This commentary addresses critical questions regarding the impact of the reduction of nicotine on changes in smoking behavior. There appears to be moderate evidence that use of reduced nicotine cigarettes (RNC) increases the likelihood of making a quit attempt among smokers unmotivated to quit and among smokers motivated to quit who also used nicotine replacement therapy (NRT). There was limited evidence that RNC combined with NRT increased smoking abstinence, regardless of motivation to quit. Several plausible mechanisms via which RNC may influence smoking behavior, including reducing dependence, are reviewed. The moderate evidence that abrupt reduction in nicotine reduces self-reported dependence as well as smoking behavior and likelihood of relapse is also reviewed. The data reviewed here suggest that abrupt switching to, and extended use of, RNC can reduce cigarette dependence and several related constructs, including the ability to quit smoking. The data reviewed in this commentary suggest that abrupt reduction in the level of nicotine in combustible cigarettes could reduce smoking behavior, nicotine dependence, and other related constructs and increase quit attempts and eventual smoking cessation.

Randomized Trial of Reduced-Nicotine Standards for Cigarettes.

BACKGROUND: The Food and Drug Administration can set standards that reduce the nicotine content of cigarettes. METHODS: We conducted a double-blind, parallel, randomized clinical trial between June 2013 and July 2014 at 10 sites. Eligibility criteria included an age of 18 years or older, smoking of five or more cigarettes per day, and no current interest in quitting smoking. Participants were randomly assigned to smoke for 6 weeks either their usual brand of cigarettes or one of six types of investigational cigarettes, provided free. The investigational cigarettes had nicotine content ranging from 15.8 mg per gram of tobacco (typical of commercial brands) to 0.4 mg per gram. The primary outcome was the number of cigarettes smoked per day during week 6. RESULTS: A total of 840 participants underwent randomization, and 780 completed the 6-week study. During week 6, the average number of cigarettes smoked per day was lower for participants randomly assigned to cigarettes containing 2.4, 1.3, or 0.4 mg of nicotine per gram of tobacco (16.5, 16.3, and 14.9 cigarettes, respectively) than for participants randomly assigned to their usual brand or to cigarettes containing 15.8 mg per gram (22.2 and 21.3 cigarettes, respectively; P<0.001). Participants assigned to cigarettes with 5.2 mg per gram smoked an average of 20.8 cigarettes per day, which did not differ significantly from the average number among those who smoked control cigarettes. Cigarettes with lower nicotine content, as compared with control cigarettes, reduced exposure to and dependence on nicotine, as well as craving during abstinence from smoking, without significantly increasing the expired carbon monoxide level or total puff volume, suggesting minimal compensation. Adverse events were generally mild and similar among groups. CONCLUSIONS: In this 6-week study, reduced-nicotine cigarettes versus standard-nicotine cigarettes reduced nicotine exposure and dependence and the number of cigarettes smoked. (Funded by the National Institute on Drug Abuse and the Food and Drug Administration Center for Tobacco Products; ClinicalTrials.gov number, NCT01681875.).

Facilitated Extinction Training to Improve Pharmacotherapy for Smoking Cessation: A Pilot Feasibility Trial.

Introduction: Varenicline reduces smoking satisfaction during the pre-cessation run-in period, which may contribute to extinction of cravings and smoking behavior. Research indicates that efficacy is enhanced when the run-in period is increased from 1 to 4 weeks, providing a longer extinction opportunity. We hypothesized that efficacy could be further enhanced by harnessing basic and applied research on extinction. We developed a pre-cessation extinction-facilitating intervention and tested its feasibility in a pilot trial. Methods: The facilitated extinction (FE) intervention comprised brief counseling and workbook-recommending strategies to maximize extinction processes during the run-in, including instructions to smoke at a normal rate across contexts and cues, and use of an extinction cue to enhance generalization. Participants were randomly assigned to one of three varenicline interventions: standard (1-week run-in), extended (4-week run-in), and extended + FE. Interventions were delivered prior to the target quit date (TQD). Assessments were conducted in weeks 1 and 4 pre-TQD and 1 and 3 months post-TQD, with focus on feasibility indices. Results: Recruitment and retention goals were met (N = 58). Treatment satisfaction was high across groups. The majority of FE participants adhered to instructions and maintained their usual smoking rate during the run-in period. Greater decreases in craving and smoking satisfaction were observed among participants in both extended groups versus the standard group (p < .005). Conclusions: Feasibility was demonstrated. Participants adhered to the FE intervention, thereby optimizing the number and variety of extinction trials. Findings support testing the novel FE smoking cessation intervention in a fully powered trial. Implications: This study expands the research on the clinical benefits of extending the pre-cessation run-in period of varenicline. It introduces the hypothesis that further benefit might be achieved by translating basic behavioral research, as well as cue-exposure research and therapy for other disorders, to improve the extinction and generalization processes thought to underlie much of varenicline's effect. A FE intervention was developed and found acceptable to smokers and feasible to implement in a research setting. The study sets the stage for a subsequent randomized controlled trial.

Effect of Immediate vs Gradual Reduction in Nicotine Content of Cigarettes on Biomarkers of Smoke Exposure: A Randomized Clinical Trial.

Importance: The optimal temporal approach for reducing nicotine to minimally or nonaddictive levels in all cigarettes sold in the United States has not been determined. Objectives: To determine the effects of immediate vs gradual reduction in nicotine content to very low levels and as compared with usual nicotine level cigarettes on biomarkers of toxicant exposure. Design, Setting, and Participants: A double-blind, randomized, parallel-design study with 2 weeks of baseline smoking and 20 weeks of intervention was conducted at 10 US sites. A volunteer sample of daily smokers with no intention to quit within 30 days was recruited between July 2014 and September 2016, with the last follow-up completed in March 2017. Interventions: (1) Immediate reduction to 0.4 mg of nicotine per gram of tobacco cigarettes; (2) gradual reduction from 15.5 mg to 0.4 mg of nicotine per gram of tobacco cigarettes with 5 monthly dose changes; or (3) maintenance on 15.5 mg of nicotine per gram of tobacco cigarettes. Main Outcomes and Measures: Between-group differences in 3 co-primary biomarkers of smoke toxicant exposure: breath carbon monoxide (CO), urine 3-hydroxypropylmercapturic acid (3-HPMA, metabolite of acrolein), and urine phenanthrene tetraol (PheT, indicator of polycyclic aromatic hydrocarbons) calculated as area under the concentration-time curve over the 20 weeks of intervention. Results: Among 1250 randomized participants (mean age, 45 years; 549 women [44%]; 958 [77%] completed the trial), significantly lower levels of exposure were observed in the immediate vs gradual reduction group for CO (mean difference, -4.06 parts per million [ppm] [95% CI, -4.89 to -3.23]; P < .0055), 3-HPMA (ratio of geometric means, 0.83 [95% CI, 0.77 to 0.88]; P < .0055), and PheT (ratio of geometric means, 0.88 [95% CI, 0.83 to 0.93]; P < .0055). Significantly lower levels of exposure were observed in the immediate reduction vs control group for CO (mean difference, -3.38 [95% CI, -4.40 to -2.36]; P < .0055), 3-HPMA (ratio of geometric means, 0.81 [95% CI, 0.75 to 0.88]; P < .0055), and PheT (ratio of geometric means, 0.86 [95% CI, 0.81 to 0.92]; P < .0055). No significant differences were observed between the gradual reduction vs control groups for CO (mean difference, 0.68 [95% CI, -0.31 to 1.67]; P = .18), 3-HPMA (ratio of geometric means, 0.98 [95% CI, 0.91 to 1.06]; P = .64), and PheT (ratio of geometric means, 0.98 [95% CI, 0.92 to 1.04]; P = .52). Conclusions and Relevance: Among smokers, immediate reduction of nicotine in cigarettes led to significantly greater decreases in biomarkers of smoke exposure across time compared with gradual reduction or a control group, with no significant differences between gradual reduction and control. Trial Registration: clinicaltrials.gov Identifier: NCT02139930.

Nicotine Withdrawal Induces Neural Deficits in Reward Processing.

INTRODUCTION: Nicotine withdrawal reduces neurobiological responses to nonsmoking rewards. Insight into these reward deficits could inform the development of targeted interventions. This study examined the effect of withdrawal on neural and behavioral responses during a reward prediction task. METHODS: Smokers (N = 48) attended two laboratory sessions following overnight abstinence. Withdrawal was manipulated by having participants smoke three regular nicotine (0.6 mg yield; satiation) or very low nicotine (0.05 mg yield; withdrawal) cigarettes. Electrophysiological recordings of neural activity were obtained while participants completed a reward prediction task that involved viewing four combinations of predictive and reward-determining stimuli: (1) Unexpected Reward; (2) Predicted Reward; (3) Predicted Punishment; (4) Unexpected Punishment. The task evokes a medial frontal negativity that mimics the phasic pattern of dopaminergic firing in ventral tegmental regions associated with reward prediction errors. RESULTS: Nicotine withdrawal decreased the amplitude of the medial frontal negativity equally across all trial types (p < .001). Exploratory analyses indicated withdrawal increased time to initiate the next trial following unexpected punishment trials (p < .001) and response time on reward trials during withdrawal was positively related to nicotine dependence (p < .001). CONCLUSIONS: Nicotine withdrawal had equivocal impact across trial types, suggesting reward processing deficits are unlikely to stem from changes in phasic dopaminergic activity during prediction errors. Effects on tonic activity may be more pronounced. Pharmacological interventions directly targeting the dopamine system and behavioral interventions designed to increase reward motivation and responsiveness (eg, behavioral activation) may aid in mitigating withdrawal symptoms and potentially improving smoking cessation outcomes. IMPLICATIONS: Findings from this study indicate nicotine withdrawal impacts reward processing signals that are observable in smokers' neural activity. This may play a role in the subjective aversive experience of nicotine withdrawal and potentially contribute to smoking relapse. Interventions that address abnormal responding to both pleasant and unpleasant stimuli may be particularly effective for alleviating nicotine withdrawal.

Effects of 6-Week Use of Reduced-Nicotine Content Cigarettes in Smokers With and Without Elevated Depressive Symptoms.

BACKGROUND: The FDA recently acquired regulatory authority over tobacco products, leading to renewed interest in whether reducing the nicotine content of cigarettes would reduce tobacco dependence in the United States. Given the association between depressive symptoms and cigarette smoking, it is important to consider whether smokers with elevated depressive symptoms experience unique benefits or negative consequences of nicotine reduction. METHODS: In this secondary analysis of a randomized clinical trial that examined the effects of cigarettes varying in nicotine content over a 6-week period in non-treatment-seeking smokers, we used linear regression to examine whether baseline depressive symptom severity (scores on the Center for Epidemiologic Studies Depression Scale [CES-D]) moderated the effects of reduced-nicotine content (RNC) cigarettes, relative to normal-nicotine content (NNC) cigarettes, on smoking rates, depressive symptom severity, and related subjective and physiological measures. RESULTS: Of the 717 participants included in this analysis, 109 (15.2%) had CES-D scores ≥ 16, indicative of possible clinical depression. Relative to NNC cigarettes, RNC cigarettes reduced smoking rates, nicotine dependence, and cigarette craving, and these effects were not significantly moderated by baseline CES-D score. A significant interaction between baseline CES-D score and cigarette condition on week 6 CES-D score was observed (p < .05); among those with CES-D scores ≥ 16 at baseline, those assigned to RNC cigarettes had lower week 6 CES-D scores than those assigned to NNC cigarettes. Among those in the lowest nicotine content conditions, biochemically confirmed compliance with the RNC cigarettes was associated with an increase in CES-D score for those with baseline CES-D scores < 16 and no change in CES-D score for those with baseline CES-D scores ≥ 16. CONCLUSIONS: These findings provide initial evidence that a reduced-nicotine standard for cigarettes may reduce smoking, without worsening depressive symptoms, among smokers with elevated depressive symptoms. IMPLICATIONS: This secondary analysis of a recent clinical trial examined whether depressive symptom severity moderated the effects of reduced-nicotine cigarettes on smoking and depressive symptoms. Results indicate that, regardless of baseline depressive symptoms, participants randomized to reduced-nicotine cigarettes had lower smoking rates, nicotine intake, nicotine dependence, and craving at week 6 post-randomization than those assigned to normal-nicotine cigarettes. In participants with higher baseline depressive symptoms, those assigned to reduced-nicotine cigarettes had lower week 6 depressive symptoms than those assigned to normal-nicotine cigarettes. These results suggest that a nicotine reduction policy could have beneficial effects for smokers, regardless of depressive symptom severity.

Reducing nicotine exposure results in weight gain in smokers randomised to very low nicotine content cigarettes.

BACKGROUND: The Food and Drug Administration can reduce the nicotine content in cigarettes to very low levels. This potential regulatory action is hypothesised to improve public health by reducing smoking, but may have unintended consequences related to weight gain. METHODS: Weight gain was evaluated from a double-blind, parallel, randomised clinical trial of 839 participants assigned to smoke 1 of 6 investigational cigarettes with nicotine content ranging from 0.4 to 15.8 mg/g or their own usual brand for 6 weeks. Additional analyses evaluated weight gain in the lowest nicotine content cigarette groups (0.4 and 0.4 mg/g, high tar) to examine the effect of study product in compliant participants as assessed by urinary biomarkers. Differences in outcomes due to gender were also explored. FINDINGS: There were no significant differences in weight gain when comparing the reduced nicotine conditions with the 15.8 mg/g control group across all treatment groups and weeks. However, weight gain at week 6 was negatively correlated with nicotine exposure in the 2 lowest nicotine content cigarette conditions. Within the 2 lowest nicotine content cigarette conditions, male and female smokers biochemically verified to be compliant on study product gained significantly more weight than non-compliant smokers and control groups. CONCLUSIONS: The effect of random assignment to investigational cigarettes with reduced nicotine on weight gain was likely obscured by non-compliance with study product. Men and women who were compliant in the lowest nicotine content cigarette conditions gained 1.2 kg over 6 weeks, indicating weight gain is a likely consequence of reduced exposure to nicotine. TRIAL REGISTRATION NUMBER: NCT01681875, Post-results.

Influence of pharmacological manipulations of NMDA and cholinergic receptors on working versus reference memory in a dual component odor span task.

Developed as a tool to assess working memory capacity in rodents, the odor span task (OST) has significant potential to advance drug discovery in animal models of psychiatric disorders. Prior investigations indicate OST performance is impaired by systemic administration of N-methyl-d-aspartate receptor (NMDA-r) antagonists and is sensitive to cholinergic manipulations. The present study sought to determine whether an impairment in OST performance can be produced by systemic administration of the competitive NMDA-r antagonist 3-(2-carboxypiperazin-4-yl)propyl-1-phosphonic acid (CPP; 3, 10, 17 mg/kg i.p.) in a unique dual-component variant of the OST, and whether this impairment is ameliorated by nicotine (0.75 mg/kg i.p.). Male Sprague-Dawley rats were trained to asymptotic level of performance on a 24-trial two-comparison incrementing nonmatching to sample OST. In addition, rats were administered a two-comparison olfactory reference memory (RM) task, which was integrated into the OST. The RM task provided an assessment of the effects of drug administration on global behavioral measures, long-term memory and motivation. Several measures of working memory (span, longest run, and accuracy) were dose dependently impaired by CPP without adversely affecting RM. Analysis of drug effects across trial blocks demonstrated a significant impairment of performance even at low memory loads, suggesting a CPP-induced deficit of olfactory short-term memory that is not load-dependent. Although nicotine did not ameliorate CPP-induced impairments in span or accuracy, it did block the impairment in longest run produced by the 10 mg/kg dose of CPP. Overall, our results indicate that performance in our 24 odor two-comparison OST is capacity dependent and that CPP impaired OST working, but not reference, memory.

The Impact of Smoking Very Low Nicotine Content Cigarettes on Alcohol Use.

BACKGROUND: Reducing the nicotine content in cigarettes could improve public health by reducing smoking and toxicant exposure, but may also have unintended consequences on alcohol use. The primary objective of this study was to examine the effect of reducing the nicotine content in cigarettes on alcohol outcomes. The secondary aim was to examine whether the effects of these cigarettes on alcohol outcomes were mediated by changes in nicotine exposure, smoking behavior, or withdrawal. METHODS: Between June 2013 and July 2014, we conducted a 7-arm, double-blind, randomized clinical trial at 10 U.S.-based sites. Daily smokers not currently interested in quitting (n = 839) were assigned to equally sized groups to smoke for 6 weeks cigarettes containing either normal nicotine content (NNC; 15.8 mg/g, 9 mg tar), moderate nicotine content (5.2 mg/g nicotine, 9 mg tar), or very low nicotine content (VLNC; 0.4 to 2.4 mg/g, 9 to 13 mg tar). This investigation focused on a subsample of current drinkers (n = 403). Each reduced nicotine content cigarette condition was compared to the NNC control condition with respect to trajectories over the 6-week period of average daily alcohol use and occurrence of binge drinking. Moderating variables were considered. Mediation analyses tested potential explanatory processes including changes in nicotine exposure, cigarettes per day, and withdrawal. RESULTS: Over time, reduced nicotine exposure and smoking rate mediated effects of VLNC cigarette use on reduced alcohol use. There was no evidence of compensatory drinking in response to nicotine reduction or nicotine withdrawal, even among subgroups expected to be at greater risk (e.g., relatively heavier drinkers, highly nicotine-dependent individuals). CONCLUSIONS: The findings suggest that compensatory drinking is unlikely to occur in response to switching to VLNC cigarettes. In contrast, reducing the nicotine content of cigarettes may reduce alcohol use (clinicalTrials.gov number, NCT01681875).

Decline in cue-provoked craving during cue exposure therapy for smoking cessation.

INTRODUCTION: Based on the principles of Pavlovian learning and extinction, cue exposure therapy (CET) involves repeated exposure to substance-associated cues to extinguish conditioned cravings and reduce the likelihood of relapse. The efficacy of CET is predicated on successful extinction, yet the process of extinction in CET trials has rarely been demonstrated. This study explored the extinction process using a cue-reactivity paradigm in smokers undergoing multiple CET sessions as part of a comprehensive smoking cessation treatment. METHODS: The sample comprised 76 moderately dependent, treatment-seeking smokers who completed at least 4 CET sessions and 6 counseling sessions. The CET and counseling sessions were scheduled twice weekly, and participants began using transdermal nicotine replacement therapy on their quit day, which occurred prior to initiation of CET. Each CET session consisted of presentation of 140 images on a computer screen, with self-reported craving as the primary measure of cue reactivity. RESULTS: Mixed-model analyses revealed a progressive decline in cue-provoked craving both within and across 6 sessions of CET. Moderator analyses showed that the decline in craving was greatest among those who displayed initial cue reactivity. CONCLUSIONS: These data are consistent with the premise that CET can produce extinction of laboratory-based cue-provoked smoking cravings and highlight important individual differences that may influence extinction. Implications for conducting cue exposure research and interventions are discussed.

An acute psychosocial stressor does not potentiate alcohol cue reactivity in non-treatment-seeking alcoholics.

BACKGROUND: Relapse risk factors, such as psychological stress and alcohol cues, are often encountered together. Understanding how they interact has the potential to improve alcoholism treatments. This study was conducted to examine whether an acute psychosocial stressor enhanced alcohol cue reactivity in non-treatment-seeking alcoholics. METHODS: Seventy-nine alcohol-dependent individuals (39 women) randomly received either the Trier Social Stress Test or a no-stress control condition. Stress reactivity was measured with serum adrenocorticotropic hormone and cortisol, mean arterial blood pressure, and subjective distress. Immediately following the stress manipulation, participants held and sniffed a neutral cue then their preferred alcoholic beverage. Cue reactivity was measured by 2 subjective measures of craving following each cue. Additionally, general craving was assessed with the Alcohol Urge Questionnaire at the beginning and end of the laboratory procedure. RESULTS: The stress manipulation showed internal validity on all measures of stress reactivity. There was not a main effect of stress nor a stress × cue interaction on either cue reactivity measure. As expected, there was a main effect of cue (alcohol > neutral cue) on both measures of cue reactivity. General craving increased during the challenge, but not differently by stress group. Magnitude of stress reactivity was not associated with magnitude of cue reactivity, and all results were independent of gender. CONCLUSION: In this well-controlled clinical laboratory study of non-treatment-seeking alcoholics, an acute psychological stressor did not make an alcohol cue a more potent urge-inducing stimulus, and stress had no effect on general alcohol craving.

Acute effects of aerobic exercise and Hatha yoga on craving to smoke.

INTRODUCTION: Recent studies have examined the effects of physical activity on craving to smoke and smoking withdrawal. The current study was designed to compare and contrast the effects of 2 different forms of physical activity on general and cue-elicited craving to smoke. METHODS: Following 1-hr nicotine abstinence, 76 daily smokers were randomly assigned to engage in a 30-min bout of cardiovascular exercise (CE; brisk walk on a treadmill), Hatha yoga (HY), or a nonactivity control condition. Participants completed measures of craving and mood, and a smoking cue reactivity assessment, before, immediately following, and approximately 20 min after the physical activity or control conditions. RESULTS: Compared with the control condition, participants in each of the physical activity groups reported a decrease in craving to smoke, an increase in positive affect, and a decrease in negative affect. In addition, craving in response to smoking cues was specifically reduced among those who engaged in CE, whereas those who engaged in HY reported a general decrease in cravings. CONCLUSIONS: This study provides further support for the use of exercise bouts for attenuating cigarette cravings during temporary nicotine abstinence. Results also suggest that CE can attenuate cravings in response to smoking cues. There are several areas for further research that may improve integration of exercise within smoking cessation treatment.

The smoking N-back: a measure of biased cue processing at varying levels of cognitive load.

INTRODUCTION: Recent cognitive models of drug addiction have emphasized attentional bias to drug-related cues. This bias manifests as increased accessibility to affect-laden drug-related content relative to less emotionally evocative stimuli and ideation. We examined whether biased processing of smoking-related content would differentially affect performance on a cognitive task as a function of smoking status and task complexity. METHODS: Twenty-one smokers and 15 nonsmokers completed increasingly difficult 1-, 2-, and 3-back versions of the Smoking N-back task. RESULTS: There were no reaction time effects that included smoking status nor was there an effect for accuracy on the 1-back task. However, smokers showed poorer accuracy on matched trials relative to nonmatched trials for smoking words on the 2- and 3-back tasks, which involve more effortful cognitive processing. Among nonsmokers, this effect was present within the 3-back condition only. CONCLUSIONS: These findings suggest that cognitive bias to drug-related cues may be modulated by task complexity. Future research on cognitive bias should better account for this factor. Additional research will be needed to validate these findings by controlling for various potential confounds (e.g., nicotine withdrawal, task fatigue) as well as determine the clinical relevance of cognitive bias across varying levels of task complexity.

Targeted smoking cessation for dual users of combustible and electronic cigarettes: a randomised controlled trial.

BACKGROUND: Although many smokers use electronic cigarettes (e-cigarettes) to quit smoking, most continue to smoke while vaping. This dual use might delay cessation and increase toxicant exposure. We aimed to test the efficacy of a self-help intervention designed to help dual users to quit smoking. METHODS: In this three-arm randomised controlled trial we recruited individuals in the USA using Facebook and multimedia advertisements. Included participants were 18 years or older, smoked at least weekly in the preceding year, and vaped at least weekly in the preceding month. We used computer generated randomisation with balanced-permuted blocks (block size 10, with 2-4-4 ratio) to allocate participants to assessment only (ASSESS group), generic smoking cessation self-help booklets (GENERIC group), or booklets targeting dual users (eTARGET group). Individuals in the generic or targeted intervention groups received monthly cessation materials for 18 months, with assessments every 3 months for 24 months. The main outcome was self-reported 7-day point-prevalence smoking abstinence at each assessment point. All randomly allocated participants were included in primary analyses using generalised estimating equations for each of 20 datasets created by multiple imputation. Analysis of the χ2s produced an F test. The trial is registered with ClinicalTrials.gov, NCT02416011, and is now closed. FINDINGS: Between July 12, 2016, and June 30, 2017, we randomly assigned 2896 dual users (575 to assessment, 1154 to generic intervention, and 1167 to targeted self-help). 7-day point-prevalence smoking abstinence increased from 14% at 3 months to 42% at 24 months (F7,541·7=67·1, p<0·0001) in the overall sample. Targeted self-help resulted in higher smoking abstinence than did assessment alone throughout the treatment period (F1,973·8=10·20, p=0·0014 [α=0·017]). The generic intervention group had abstinence rates between those of the assessment and targeted groups, but did not significantly differ from either when adjusted for multiple comparisons (GENERIC vs eTARGET F1,1102·5=1·79, p=0·18 [α=0·05]; GENERIC vs ASSESS F1,676·7=4·29, p=0·039 [α=0·025]). Differences between study groups attenuated after the interventions ended. INTERPRETATION: A targeted self-help intervention with high potential for dissemination could be efficacious in promoting smoking cessation among dual users of combustible cigarettes and e-cigarettes. FUNDING: National Institute on Drug Abuse, National Cancer Institute.