Smartphone-Based Contingency Management Intervention to Improve Pre-Exposure Prophylaxis Adherence: Pilot Trial

Background

Pre-exposure prophylaxis (PrEP) provides a strong preventative benefit to individuals at risk for HIV. While PrEP adherence is highly correlated with its efficacy, adherence rates are variable both across and within persons.

Objective

The objective of this study was to develop and pilot-test a smartphone-based intervention, known as mSMART, that targets PrEP adherence. mSMART provides contingency management in the form of monetary incentives for daily PrEP adherence based on a real-time adherence assessment using a camera-based medication event-monitoring tool as well as medication reminders, PrEP education, individualized behavioral strategies to address PrEP adherence barriers, and medication adherence feedback.

Methods

This was a 4-week open-label, phase I trial in a community sample of young men who have sex with men already on PrEP (N=10).

Results

Although adherence composite scores corresponding to PrEP biomarkers indicated that 90% (9/10) of the sample already had an acceptable baseline adherence in the protective range, by the end of the 4-week period, the scores improved for 30% (3/10) of the sample—adherence did not worsen for any participants. Participants reported mean PrEP adherence rates of 91% via daily entries in mSMART. At the end of the 4-week period, participants indicated acceptable ratings of satisfaction, usability, and willingness to recommend mSMART to others. There were no technical difficulties associated with smartphone compatibility, user misunderstandings about mSMART features that interfered with daily use, or study attrition.

Conclusions

This study is the first to apply contingency management to PrEP adherence. Findings indicated that mSMART is feasible and acceptable. Such an adherence intervention administered via a user-friendly smartphone app can allow for widespread dissemination. Future efficacy trials are needed.

Trial Registration

ClinicalTrials.gov NCT02895893; https://clinicaltrials.gov/ct2/show/NCT02895893 (Accessed by Webcite at http://www.webcitation.org/72JskjDJq)

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.

Adherence to Pharmacological Smoking Cessation Interventions: A Literature Review and Synthesis of Correlates and Barriers

Introduction

Efficacious pharmacological interventions for smoking cessation are available, but poor adherence to these treatments may limit these interventions overall impact. To improve adherence to smoking cessation interventions, it is first necessary to identify and understand smoker-level characteristics that drive nonadherence (ie, nonconformance with a provider's recommendation of timing, dosage, or frequency of medication-taking during the prescribed length of time).

Methods

We present a literature review of studies examining correlates of, or self-reported reasons for, nonadherence to smoking cessation pharmacotherapies. Studies were identified through PubMed-using MeSH terms, Embase-using Emtree terms, and ISI Web of Science.

Results and Conclusions

This literature review included 50 studies that examined nonpreventable (eg, sociodemographics) and preventable (eg, forgetfulness) factors associated with adherence to smoking cessation medication and suggestions for overcoming some of the identified barriers. Systematic study of this topic would be facilitated by consistent reporting of adherence and correlates thereof in the literature, development of consistent definitions of medication adherence across studies, utilization of more objective measures of adherence (eg, blood plasma levels vs. self-report) in addition to reliance on self-reported adherence.

Implications

This article provides the most comprehensive review to date on correlates of adherence to pharmacological smoking cessation interventions. Challenges and specific gaps in the literature that should be a priority for future research are discussed. Future priorities include additional research, particularly among vulnerable populations of smokers, developing standardized definitions of adherence and methods for measuring adherence, regular assessment of cessation pharmacotherapy adherence in the context of research and clinical practice, and development of novel treatments aimed at preventable barriers to medication adherence.

Predicting Smoking Events with a Time-Varying Semi-Parametric Hawkes Process Model

Health risks from cigarette smoking - the leading cause of preventable death in the United States - can be substantially reduced by quitting. Although most smokers are motivated to quit, the majority of quit attempts fail. A number of studies have explored the role of self-reported symptoms, physiologic measurements, and environmental context on smoking risk, but less work has focused on the temporal dynamics of smoking events, including daily patterns and related nicotine effects. In this work, we examine these dynamics and improve risk prediction by modeling smoking as a self-triggering process, in which previous smoking events modify current risk. Specifically, we fit smoking events self-reported by 42 smokers to a time-varying semi-parametric Hawkes process (TV-SPHP) developed for this purpose. Results show that the TV-SPHP achieves superior prediction performance compared to related and existing models, with the incorporation of time-varying predictors having greatest benefit over longer prediction windows. Moreover, the impact function illustrates previously unknown temporal dynamics of smoking, with possible connections to nicotine metabolism to be explored in future work through a randomized study design. By more effectively predicting smoking events and exploring a self-triggering component of smoking risk, this work supports development of novel or improved cessation interventions that aim to reduce death from smoking.

Effects of reduced nicotine content cigarettes on individual withdrawal symptoms over time and during abstinence

In the United States, the Food and Drug Administration (FDA) has initiated a public dialogue about reducing the nicotine content of cigarettes. A reduced-nicotine standard could increase withdrawal symptoms among current smokers. We examined the impact of switching smokers to cigarettes that varied in nicotine content on withdrawal symptoms over 6 weeks. A secondary analysis (N = 839) of a 10-site, double-blind clinical trial of nontreatment-seeking smokers was completed. Participants were instructed to smoke study cigarettes, containing 0.4 to 15.8 mg of nicotine/g of tobacco, for 6 weeks and were then abstinent overnight. Using latent growth curves, trajectories of individual withdrawal symptoms were compared between the reduced nicotine content (RNC) conditions and a normal nicotine content (NNC) condition. Path analyses compared symptoms after overnight abstinence. Relative to NNC cigarettes, participants smoking RNC cigarettes had increased anger/irritability/frustration and increased appetite/weight gain during the initial weeks, but the symptoms resolved by Week 6. Individuals who were biochemically verified as adherent with using only the 0.4 mg/g cigarettes had higher sadness levels (Cohen's d = .40) at Week 6 compared with the NNC condition, although symptoms were mild. After a post-Week 6 overnight abstinence challenge, some RNC conditions relative to NNC condition exhibited reduced withdrawal. Individuals who were biochemically confirmed as adherent to the lowest nicotine condition experienced only mild and transient symptom elevations. Thus, a reduced-nicotine standard for cigarettes produced a relatively mild and temporary increase in withdrawal among nontreatment-seeking smokers (ClinicalTrials.gov No. NCT01681875). (PsycINFO Database Record

Perceived risk of developing smoking-related disease among persons living with HIV

Perceived risk of smoking is associated with smoking status, interest in quitting, cessation attempts, and quit success. Research is needed to explore risk perceptions of developing smoking-related disease among persons living with HIV (PLWH). Data came from 267 HIV-positive smokers who completed an online survey assessing perceived health risks associated with (a) generic smoking status; (b) generic non-smoking status; (c) their own personal current smoking; and (d) a hypothetical situation in which they were a non-smoker. PLWH perceived greater risk associated with their current smoking versus hypothetical personal non-smoking (p's < 0.001), and greater risks associated with generic smoking status compared with their current smoking (p's < 0.001). Being on HIV medication (β = 0.65, 95% CI = 0.17, 1.12), interest in quitting smoking (β = 0.89, 95% CI = 0.45, 1.32), and having an HIV healthcare provider who has recommended cessation (β = 1.04, 95% CI = 0.42, 1.67) were positively associated with perceived risk of developing smoking-related diseases. Findings have implications for developing targeted interventions to correct misperceptions regarding the health risks of smoking among PLWH, a population at particular risk for smoking and smoking-related morbidity and mortality.

Decline in the perceived risk of cigarette smoking between 2006 and 2015: Findings from a U.S. nationally representative sample

INTRODUCTION

Perceived risk of smoking is associated with smoking status, interest in quitting, quit attempts, and sustained quitting. Tracking and reporting of risk perceptions is integral to inform regulation and education. However, no research describes temporal changes in perceived great risk of smoking in the U.S. using nationally representative data.

METHODS

Data came from the 2006-2015 National Survey on Drug Use and Health (NSDUH). Time trends were assessed for the population overall, stratified by smoking status and by sociodemographic characteristics. Linear time trends of perceived great risk (versus other risk) were assessed using logistic regression, with survey year as the predictor.

RESULTS

Perceived great risk of smoking declined significantly among the entire population between 2006 and 2015 (73.89% versus 72.89%). Perceived great risk also decreased among all smoking statuses: daily (51.16% versus 48.19%), non-daily (64.12% versus 58.44%, former (79.57% versus 77.12%), and non-smokers (79.32% versus 77.10%). The prevalence of perceived great risk declined between 2006 and 2015 among both males and females; the rate of decline was more rapid among females (aOR = 0.98, 95% CI = 0.97, 0.98 versus aOR = 0.99, 95% CI = 0.98, 0.99). Older age, African American and Hispanic race/ethnicity, educational attainment, and non-daily, former, and never smoking statuses were positively associated with perceived great risk of smoking.

DISCUSSION

Perceived risk of smoking has declined over a 10-year period in the U.S. Declines in perceived risk indicate the need for innovative interventions to reinforce the harms associated with smoking. Differential rates of decline among males and females indicate the need for sex-specific interventions.

ADHD, Smoking Withdrawal, and Inhibitory Control: Results of a Neuroimaging Study with Methylphenidate Challenge

Smoking withdrawal negatively impacts inhibitory control, and these effects are greater for smokers with preexisting attention problems, such as attention deficit/hyperactivity disorder (ADHD). The current study preliminarily evaluated changes in inhibitory control-related behavior and brain activation during smoking withdrawal among smokers with ADHD. Moreover, we investigated the role of catecholamine transmission in these changes by examining the effects of 40 mg methylphenidate (MPH) administration. Adult daily smokers with (n=17) and without (n=20) ADHD completed fMRI scanning under each of three conditions: (a) smoking as usual+placebo; (b) 24 h smoking abstinence+placebo and (c) 24 h smoking abstinence+MPH. Scan order was randomized and counterbalanced. Participants completed a modified Go/No-Go task to assess both sustained and transient inhibitory control. Voxelwise analysis of task-related BOLD signal revealed a significant group-by-abstinence interaction in occipital/parietal cortex during sustained inhibition, with greater abstinence-induced decreases in activation observed among ADHD smokers compared with non-ADHD smokers. Changes in behavioral performance during abstinence were associated with changes in activation in regions of occipital and parietal cortex and bilateral insula during sustained inhibition in both groups. MPH administration improved behavioral performance and increased sustained inhibitory control-related activation for both groups. During transient inhibition, MPH increased prefrontal activation for both groups and increased striatal activation only among ADHD smokers. These preliminary findings suggest that abstinence-induced changes in catecholamine transmission in visual attention areas (eg, occipital and superior parietal cortex) may be associated with inhibitory control deficits and contribute to smoking vulnerability among individuals with ADHD.

Perceptual Characterization of the Macronutrient Picture System (MaPS) for Food Image fMRI

Food image fMRI paradigms are used widely for investigating the neural basis of ingestive behavior. However, these paradigms have not been validated in terms of ingestive behavior constructs, engagement of food-relevant neural systems, or test-retest reliability, making the generalizability of study findings unclear. Therefore, we validated the Macronutrient Picture System (MaPS) (McClernon et al., 2013), which includes food images from the six categories represented in the Geiselman Food Preference Questionnaire (FPQ) (Geiselman et al., 1998). Twenty-five healthy young adults (n = 21 female, mean age = 20.6 ± 1.1 years, mean BMI = 22.1 ± 1.9 kg/m²) rated the MaPS images in terms of visual interest, appetitive quality, nutrition, emotional valence, liking, and frequency of consumption, and completed the FPQ. In a second study, 12 individuals (n=8 female, mean age = 25.0 ± 6.5 years, mean BMI = 28.2 ± 8.7 kg/m²) viewed MaPS and control images (vegetables and non-food) during two separate 3T BOLD fMRI scans after fasting overnight. Intuitively, high fat/high sugar (HF/HS) and high fat/high complex carbohydrate (HF/HCCHO) images achieved higher liking and appetitive ratings, and lower nutrition ratings, than low fat/low complex carbohydrate/high protein (LF/LCHO/HP) images on average. Within each food category, FPQ scores correlated strongly with MaPS image liking ratings (p < 0.001). Brain activation differences between viewing images of HF/HS and vegetables, and between HF/HCCHO and vegetables, were seen in several reward-related brain regions (e.g., putamen, insula, and medial frontal gyrus). Intra-individual, inter-scan agreement in a summary measure of brain activation differences in seven reward network regions of interest was high (ICC = 0.61), and was even higher when two distinct sets of food images with matching visual ratings were shown in the two scans (ICC = 0.74). These results suggest that the MaPS provides valid representation of food categories and reliably activates food-reward-relevant neural systems.

Implicit Attitudes and Smoking Behavior in a Smoking Cessation Induction Trial

INTRODUCTION

Although studies have suggested that implicit attitudes may predict smoking-related decisions, evidence that changes in implicit attitudes toward smoking are related to changes in smoking behavior is lacking. Using data from a trial comparing interventions to induce quit attempts among unmotivated smokers, this study examined whether changes in implicit attitudes were associated with quit attempts and cessation after controlling for explicit motivation.

METHODS

Daily smokers recruited from the community completed measures of implicit attitudes (Implicit Association Test) and explicit measure of motivation to smoke at baseline, mid-intervention (week 12 [W12]) and follow-up (week 26 [W26]). Quit attempts and cessation were assessed at follow-up, and cessation was biochemically verified.

RESULTS

As hypothesized, Implicit Association Test scores became more negative from baseline to W12, a change that was sustained at follow-up. Logistic regression analyses in which implicit attitudes were used to predict smoking outcomes revealed that negative changes in implicit attitudes from baseline to W12 and from baseline to W26 were significantly related to quit attempts (OR = 0.71, 95% CI [0.52, 0.97], p < .05 for both) independent of explicit motivation. Negative changes in implicit attitudes from baseline to W26 were significantly related to cessation (OR = 0.50, 95% CI [0.25, 1.00], p < .05).

CONCLUSIONS

Negative changes in implicit attitudes were associated with positive changes in smoking behavior independent of explicit motivation. This result indicates that smoking cessation interventions may be enhanced by incorporating strategies to change implicit attitudes, and that changes in implicit attitudes are also potentially important intervention outcomes.

IMPLICATIONS

Smoking cessation interventions may be improved by going beyond the current focus on explicit psychological constructs and targeting automatic cognitive processes such as implicit attitudes. The results are encouragement to examine how best to manipulate smokers' implicit attitudes as well as to determine the effect on their smoking behavior.

Perceived nicotine content of reduced nicotine content cigarettes is a correlate of perceived health risks

BACKGROUND

Reducing cigarette nicotine content may reduce smoking. Studies suggest that smokers believe that nicotine plays a role in smoking-related morbidity. This may lead smokers to assume that reduced nicotine means reduced risk, and attenuate potential positive effects on smoking behaviour.

METHODS

Data came from a multisite randomised trial in which smokers were assigned to use cigarettes varying in nicotine content for 6 weeks. We evaluated associations between perceived and actual nicotine content with perceived health risks using linear regression, and associations between perceived nicotine content and perceived health risks with smoking outcomes using linear and logistic regression.

FINDINGS

Perceived-not actual-nicotine content was associated with perceived health risks; compared with those perceiving very low nicotine, individuals who perceived low (β=0.72, 95% CI 0.26 to 1.17), moderate (β=1.02, 95% CI 0.51 to 1.53) or high/very high nicotine (β=1.66, 95% CI 0.87 to 2.44) perceived greater health risks. Nevertheless, individuals perceiving low (OR=0.48, 95% CI 0.32 to 0.71) or moderate nicotine (OR=0.42, 95% CI 0.27 to 0.66) were less likely than those perceiving very low nicotine to report that they would quit within 1 year if only investigational cigarettes were available. Lower perceived risk of developing other cancers and heart disease was also associated with fewer cigarettes/day at week 6.

CONCLUSIONS

Although the perception of reduced nicotine is associated with a reduction in perceived harm, it may not attenuate the anticipated beneficial effects on smoking behaviour. These findings have implications for potential product standards targeting nicotine and highlight the need to clarify the persistent harms of reduced nicotine combusted tobacco products.

A Pilot Trial Examining African American and White Responses to Algorithm-Guided Smoking Cessation Medication Selection in Persons Living with HIV

Algorithm-based treatments (AT) may be an effective clinical tool to aid HIV clinicians in prescribing pharmacotherapy to increase smoking cessation among people living with HIV (PLWH). Initial results from AT indicated significant increases in abstinence self-efficacy and medication utilization and declines in cigarettes smoked per day across time. Given historical racial disparities, it is unclear if both African Americans and White smokers would benefit equally from this type of intervention. Thus, the aim of this study was to examine racial differences in response to AT guided smoking cessation for African American and White smokers living with HIV. One hundred PLWH smokers (n = 100) were randomized to receive either AT guided smoking cessation or Treatment as Usual (TAU) which consisted of instructing participants to talk to a provider about smoking cessation assistance when ready to make a quit attempt. Participants were African American (75%) and White (25%) and majority men (71%) who had never been married (56%). African Americans smoked fewer cigarettes and were more likely to smoke mentholated cigarettes compared to White smokers at baseline. African Americans increased their use of other tobacco products (cigars/cigarillos) over time relative to White smokers. A significant interaction between race and quit goal was observed, with White smokers who reported complete abstinence as their goal having higher quit rates, while African Americans who reported a goal other than complete abstinence demonstrating higher quit rates. The increased use of cigars/cigarillos during quit attempts as well as having a goal other than complete abstinence should be considered when applying algorithm based interventions for PLWH African American smokers.

Association Between Baseline Corticothalamic-Mediated Inhibitory Control and Smoking Relapse Vulnerability

IMPORTANCE

Tobacco use disorder is associated with dysregulated neurocognitive function in the right inferior frontal gyrus (IFG)-one node in a corticothalamic inhibitory control (IC) network.

OBJECTIVE

To examine associations between IC neural circuitry structure and function and lapse/relapse vulnerability in 2 independent studies of adult smokers.

DESIGN, SETTING, AND PARTICIPANTS

In study 1, treatment-seeking smokers (n = 81) completed an IC task during functional magnetic resonance imaging (fMRI) before making a quit attempt and then were followed up for 10 weeks after their quit date. In study 2, a separate group of smokers (n = 26) performed the same IC task during fMRI, followed by completing a laboratory-based smoking relapse analog task. Study 1 was performed at Duke University Medical Center between 2008 and 2012; study 2 was conducted at the Medical University of South Carolina between 2013 and 2016.

MAIN OUTCOMES AND MEASURES

Associations between corticothalamic-mediated IC, gray-matter volume, and smoking lapse/relapse.

RESULTS

Of the 81 study participants in study 1 (cessation study), 45 were women (56%), with mean (SD) age, 38.4 (10.2) years. In study 1, smoking relapse was associated with less gray-matter volume (F1,74 = 28.32; familywise error P threshold = 0.03), greater IC task-related blood oxygenation level-dependent (BOLD) response in the right IFG (F1,78 = 14.87) and thalamus (F1,78 = 14.97) (P < .05), and weaker corticothalamic task-based functional connectivity (tbFC) (F1,77 = 5.87; P = .02). Of the 26 participants in study 2 (laboratory study), 15 were women (58%), with mean (SD) age, 34.9 (10.3). Similar to study 1, in study 2, greater IC-BOLD response in the right IFG (t23 = -2.49; β = -0.47; P = .02), and weaker corticothalamic tbFC (t22 = 5.62; β = 0.79; P < .001) were associated with smoking sooner during the smoking relapse-analog task. In both studies, corticothalamic tbFC mediated the association between IC performance and smoking outcomes.

CONCLUSIONS AND RELEVANCE

In these 2 studies, baseline differences in corticothalamic circuitry function were associated with mediated IC and smoking relapse vulnerability. These findings warrant further examination of interventions for augmenting corticothalamic neurotransmission and enhancing IC during the course of tobacco use disorder treatment.

Smoking environment cues reduce ability to resist smoking as measured by a delay to smoking task

INTRODUCTION

Environments associated with smoking may promote lapse and relapse in smokers attempting to quit. Here we examined the effects of exposure to visual smoking environment cues on smoking urge and the ability to resist smoking, as measured with a delay-to-smoking task in which monetary contingencies are provided for resisting smoking.

METHODS

Adult daily smokers (n=22) completed two experimental sessions, each following 6h smoking abstinence. Sessions differed only in the type of cue participants were exposed to (smoking environments vs. nonsmoking environments). Participants completed subjective ratings of smoking urge, withdrawal and other reactions (i.e. craving, affect). Behavioral outcomes on the delay-to-smoking task included latency to first cigarette, number of cigarettes smoked and average number of puffs per cigarette.

RESULTS

Across cue exposure sessions, 64% of participants initiated smoking (no effect of condition was observed). However, exposure to smoking environments as compared to the nonsmoking environments resulted in greater craving, faster initiation of smoking, and more smoked cigarettes. Greater craving was associated with a shorter time to initiate smoking, but this effect did not differ across sessions. In contrast, withdrawal was more strongly associated with number of cigarettes smoked during smoking environment sessions.

CONCLUSION

Together, these results suggest smoking environments increase smoking urge and promote smoking behavior. Further research is necessary to examine the specific and interactive effects of smoking-related environments on real-world smoking lapse and relapse.

Use and Perceived Risk of Electronic Cigarettes Among North Carolina Middle and High School Students

PURPOSE

Electronic cigarette (e-cigarette) use continues to rise among adolescents, but little is known regarding their risk perceptions of e-cigarette use. We aimed to describe the lifetime use and perceived risk of e-cigarette use in the context of other risk-taking behaviors among adolescents in North Carolina.

METHODS

Data were derived from the 2015 North Carolina Youth Risk Behavior Survey, which was administered to 503 middle school and 444 high school students in the Chapel Hill-Carrboro public school district. Survey participants self-reported their sex; ethnicity; school grade; ever-use of cigarettes, e-cigarettes, alcohol, and other illicit substances; perceived risk of harm of these products; and perceived view of their parents' and friends' perceptions of these products. Logistic regression analyses were used to assess associations between student-reported characteristics, risk behaviors, perceived product risk, and ever-use of e-cigarettes.

RESULTS

This study found that 4.6% of middle school students and 37.2% of high school students reported ever-use of e-cigarettes. E-cigarette use increased and perception of e-cigarette risk decreased with advancing grade. Ever-use of e-cigarettes surpassed ever-use of combustible cigarettes at all grades; 49.4% of e-cigarette users had never smoked cigarettes. The perception that friends view e-cigarette use as "wrong" correlated negatively with e-cigarette use (adjusted odds ratio = 0.43; 95% confidence interval, 0.19-0.97).

LIMITATIONS

Self-reported results from students in one school district have limited generalizability to larger groups.

CONCLUSION

E-cigarette use among adolescents in North Carolina correlates positively with perceived friends' views of e-cigarettes, and use correlates negatively with personal perception of the risk of e-cigarettes. Based on our survey results, education and public health intervention regarding e-cigarette use may be best targeted at youth prior to their transition to high school.

Evaluation of a reduced nicotine product standard: Moderating effects of and impact on cannabis use

INTRODUCTION

The Family Smoking Prevention and Tobacco Control Act authorized the FDA to reduce the nicotine content in cigarettes. Research is needed to guide proposed regulations, including evaluation of consequences to public health. This study evaluated how a reduced nicotine product standard might be moderated by and impact cannabis use.

METHODS

Secondary analysis of a controlled clinical trial examining the effects of nicotine content in cigarettes in adult daily smokers. Linear regression assessed whether baseline cannabis use moderated behavioral, subjective, or physiological effects of smoking very low nicotine content (VLNC) versus normal nicotine content (NNC) cigarettes. Repeated measures analysis of associations between nicotine condition and prevalence and frequency of cannabis use was completed using generalized estimating equations (GEE).

RESULTS

Cannabis use did not moderate most of the following effects of VLNC cigarettes: Among cannabis users and non-users, smokers randomized to VLNC cigarettes reported lower nicotine dependence, cigarettes per day, biomarkers of nicotine exposure, and craving compared to smokers randomized to NNC cigarettes. Non-cannabis using smokers randomized to VLNC cigarettes also reported lower smoking dependence motives and had lower tobacco-specific nitrosamine exposure and total puff volume versus smokers randomized to NNC cigarettes. For cannabis users, smokers randomized to VLNC cigarettes reported decreased positive affect. VLNC cigarette use did not impact the prevalence or frequency of cannabis use.

DISCUSSION

Findings provide evidence that nicotine reduction in cigarettes could have beneficial effects on cigarette smoking regardless of cannabis use. Results suggest that transitioning to VLNC cigarettes is unlikely to alter current rates of cannabis use.

"I Use Weed for My ADHD": A Qualitative Analysis of Online Forum Discussions on Cannabis Use and ADHD

Background

Attention-deficit/hyperactivity disorder (ADHD) is a risk factor for problematic cannabis use. However, clinical and anecdotal evidence suggest an increasingly popular perception that cannabis is therapeutic for ADHD, including via online resources. Given that the Internet is increasingly utilized as a source of healthcare information and may influence perceptions, we conducted a qualitative analysis of online forum discussions, also referred to as threads, on the effects of cannabis on ADHD to systematically characterize the content patients and caregivers may encounter about ADHD and cannabis.

Methods

A total of 268 separate forum threads were identified. Twenty percent (20%) were randomly selected, which yielded 55 separate forum threads (mean number of individual posts per forum thread = 17.53) scored by three raters (Cohen’s kappa = 0.74). A final sample of 401 posts in these forum threads received at least one endorsement on predetermined topics following qualitative coding procedures.

Results

Twenty-five (25%) percent of individual posts indicated that cannabis is therapeutic for ADHD, as opposed to 8% that it is harmful, 5% that it is both therapeutic and harmful, and 2% that it has no effect on ADHD. This pattern was generally consistent when the year of each post was considered. The greater endorsement of therapeutic versus harmful effects of cannabis did not generalize to mood, other (non-ADHD) psychiatric conditions, or overall domains of daily life. Additional themes emerged (e.g., cannabis being considered sanctioned by healthcare providers).

Conclusions

Despite that there are no clinical recommendations or systematic research supporting the beneficial effects of cannabis use for ADHD, online discussions indicate that cannabis is considered therapeutic for ADHD—this is the first study to identify such a trend. This type of online information could shape ADHD patient and caregiver perceptions, and influence cannabis use and clinical care.

Non-cigarette tobacco and poly-tobacco use among persons living with HIV drawn from a nationally representative sample

INTRODUCTION

Smoking is more prevalent among persons living with HIV (PLWH) than the general population. Little is known about the prevalence of non-cigarette tobacco and poly-tobacco use (PTU; using multiple tobacco products) among this population, which, in the general population is associated with poor health and cessation outcomes. We aimed to characterize the prevalence of cigarette and non-cigarette tobacco use, PTU, and correlates of tobacco use status among a nationally-representative sample of PLWH.

METHODS

Data came from 472 HIV-positive adults from the 2005-2013 National Survey on Drug Use and Health (NSDUH).

RESULTS

The prevalence of PTU overall was 8.7% (95% CI=5.6-13.2), and 16.6% (95% CI=10.2-25.7) among past-year tobacco users. In multinomial logistic regression analyses, participants with a high school education or greater (aRRR=2.03, 95% CI=1.03-4.00) were more likely to be non-tobacco users than single product users. Past year drug users (aRRR=0.35, 95% CI=0.19-0.66) and past month binge drinkers (aRRR=0.24, 95% CI=0.12-0.50) were less likely to be non-tobacco users than single product users. Compared to 18-25 year olds, individuals age 26-34 (aRRR=0.13, 95% CI=0.03-0.65) and 35+ (aRRR=0.24, 95% CI=0.09-0.63), and with lifetime anxiety disorder(s) (aRRR=0.18, 95% CI=0.06-0.57) were less likely to be PTUs as compared to single product users. Individuals who reported liking to test themselves by doing risky things were more likely to be PTUs than single product users (aRRR=2.95, 95% CI=1.27-6.84).

CONCLUSIONS

PTU was slightly higher than in the general population, and should be taken into account when developing cessation interventions tailored to tobacco users living with HIV.

The fMRI BOLD response to unisensory and multisensory smoking cues in nicotine-dependent adults

Given that the vast majority of functional magnetic resonance imaging (fMRI) studies of drug cue reactivity use unisensory visual cues, but that multisensory cues may elicit greater craving-related brain responses, the current study sought to compare the fMRI BOLD response to unisensory visual and multisensory, visual plus odor, smoking cues in 17 nicotine-dependent adult cigarette smokers. Brain activation to smoking-related, compared to neutral, pictures was assessed under cigarette smoke and odorless odor conditions. While smoking pictures elicited a pattern of activation consistent with the addiction literature, the multisensory (odor+picture) smoking cues elicited significantly greater and more widespread activation in mainly frontal and temporal regions. BOLD signal elicited by the multisensory, but not unisensory cues, was significantly related to participants' level of control over craving as well. Results demonstrated that the co-presentation of cigarette smoke odor with smoking-related visual cues, compared to the visual cues alone, elicited greater levels of craving-related brain activation in key regions implicated in reward. These preliminary findings support future research aimed at a better understanding of multisensory integration of drug cues and craving.

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.).

Suboptimal foraging behavior: a new perspective on gambling

Why do people gamble? Conventional views hold that gambling may be motivated by irrational beliefs, risk-seeking, impulsive temperament, or dysfunction within the same reward circuitry affected by drugs of abuse. An alternate, unexplored perspective is that gambling is an extension of natural foraging behavior to a financial environment. However, when these foraging algorithms are applied to stochastic gambling outcomes, undesirable results may occur. To test this hypothesis, we recruited participants based on their frequency of gambling-yearly (or less), monthly, and weekly-and investigated how gambling frequency related to irrational beliefs, risk-taking/impulsivity, and foraging behavior. We found that increased gambling frequency corresponded to greater gambling-related beliefs, more exploratory choices on an explore/exploit foraging task, and fewer points earned on a Patchy Foraging Task. Gambling-related beliefs negatively related to performance on the Patchy Foraging Task, indicating that individuals with more gambling-related cognitions tended to leave a patch too quickly. This indicates that frequent gamblers have reduced foraging ability to maximize rewards; however, gambling frequency -and by extension, poor foraging ability- was not related to risk-taking or impulsive behavior. These results suggest that gambling reflects the application of a dysfunctional foraging process to financial outcomes.

Smoking abstinence and neurocognition: implications for cessation and relapse

In this chapter, we review the last decade of research on the effects of smoking abstinence on various forms of neurocognition, including executive function (working memory, sustained attention, response inhibition), reward processing, and cue-reactivity. In our review we identify smoking abstinence-induced deficits in executive function mediated by effects on frontal circuitry, which in turn is known to be affected by modulation of cholinergic, dopaminergic, and other neurotransmitter systems. We also review evidence that smoking abstinence blunts reactivity to non-drug reinforcers-a finding that is consistent with results in the animal literature. Finally, our review of cue-reactivity indicates that smoking abstinence does not appear to amplify cue-provoked craving, although it may increase attentional bias to smoking-related cues. Inconsistencies across findings and potential contributing factors are discussed. In addition, we review the literature on the effects of nicotine and non-nicotine factors in neurocognition. Finally, we provide a multi-factor model and an agenda for future research on the effects of smoking abstinence on neurocognition. The model includes four distinct yet interacting factors, including: Negative Reinforcement, Drug-Reward Bias, Goal and Skill Interference, and Non-Cognitive Factors. Additional research is needed to further evaluate the scope and time-course of abstinence-induced changes in neurocognition, the mechanisms that underlie these changes and the specific role of these processes in drug reinforcement, lapse, and relapse.

Smoking automaticity and tolerance moderate brain activation during explore-exploit behavior

The adaptive trade-off between exploration and exploitation is a key component in models of reinforcement learning. Over the past decade, these models have been applied to the study of reward-seeking behavior. Drugs of addiction induce reward-seeking behavior and modify its underlying neurophysiological processes. These neurophysiological changes may underlie a behavioral shift from a flexible, exploratory mode to a focused, exploitative mode, which precedes the development of inflexible, habitual drug use. The goal of this study was to investigate the relationship between explore/exploit behavior and drug addiction by examining the neural correlates of this behavior in cigarette smokers. Participants (n=22) with a range of smoking behaviors completed a smoking dependence motives questionnaire and played a 6-armed bandit task while undergoing functional magnetic resonance imaging (fMRI). Exploratory behavior produced greater activation in the bilateral superior parietal and bilateral frontal cortices than exploitative behavior. Exploitative behavior produced greater activation in the bilateral superior and middle temporal gyri than exploratory behavior. fMRI data and orthogonalized smoking dependence motive scores were entered into multiple linear regression analyses. After controlling for nicotine tolerance, smoking automaticity positively correlated with activation in the same bilateral parietal regions preferentially activated by exploratory choices. These preliminary results link smoking dependence motives to variation in the neural processes that mediate exploratory decision making.