Nicotine, alcohol, and caffeine use among individuals with untreated obstructive sleep apnea

BACKGROUND

Psychoactive substance use (i.e., nicotine, alcohol, and caffeine) has substantial effects on sleep architecture in healthy individuals, but their effects in those with obstructive sleep apnea (OSA) have not been well described. We aimed to describe the association between psychoactive substance use and sleep characteristics and daytime symptoms in individuals with untreated OSA.

METHODS

We performed a secondary, cross-sectional analysis of The Apnea Positive Pressure Long-term Efficacy Study (APPLES). Exposures included current smoking, alcohol and caffeine use in individuals with untreated OSA. Outcome domains included subjective and objective sleep characteristics, daytime symptoms, and comorbid conditions. Linear or logistic regression assessed the association between substance use and each domain (e.g., self-reported sleep duration, total polysomnographic sleep time, sleepiness, and anxiety).

RESULTS

Of the 919 individuals with untreated OSA, 116 (12.6%) were current cigarette smokers, 585 (63.7%) were moderate or heavy alcohol users, and 769 (83.7%) were moderate or heavy caffeine users. Participants were on average 52.2±11.9 years old, 65.2% were male with a median BMI of 30.6 (IQR: 27.2, 35.9, kg/m2). Current smokers exhibited lower sleep duration (0.3 h), longer sleep latency (5 min) compared with non-smokers (all p-values < 0.05). People with heavy or moderate alcohol use exhibited more REM sleep (2.5 and 5% of total sleep time respectively), as did those with moderate caffeine use (2%, p-values < 0.05). The combined smoker plus caffeine group exhibited shorter sleep duration (0.4 h, p-value < 0.05) and higher risk for chronic pain [Odds Ratio (95%CI) = 4.83 (1.57, 14.9) compared with non-users.

CONCLUSIONS

Psychoactive substance use is associated with sleep characteristics and clinically relevant correlates in people with untreated OSA. Further investigation into the effects that various substances have on this population may present opportunities to understand disease mechanisms more fully and increase the effectiveness of treatment in OSA.

Nicotine flux as a powerful tool for regulating nicotine delivery from e-cigarettes: Protocol of two complimentary randomized crossover clinical trials

INTRODUCTION

Electronic cigarette (EC) use has increased rapidly in the last decade, especially among youth. Regulating nicotine delivery from ECs could help curb youth uptake and leverage EC use in harm reduction yet is complicated by varying device and liquid variables that affect nicotine delivery. Nicotine flux, the nicotine emission rate, is a parameter that incorporates these variables and focuses on the performance rather than the design of an EC. Nicotine flux therefore could be a powerful regulatory tool if it is shown empirically to predict nicotine delivery and subjective effects related to dependence.

METHODS AND ANALYSIS

This project consists of two complementary clinical trials. In Trial I, we will examine the relationship between nicotine flux and the rate and dose of nicotine delivery from ECs, hence, impacting abuse liability. It will also examine the extent to which this relationship is mediated by nicotine form (i.e., freebase versus protonated). At Yale School of Medicine (YSM), study participants will puff EC devices under conditions that differ by flux and form, while arterial blood is sampled in high time resolution. In Trial II, we will assess the relationship between nicotine flux, form, and subjective effects. At the American University of Beirut (AUB), participants will use EC devices with varying nicotine fluxes and forms, while dependency measures, such as the urge to use ECs, nicotine craving, and withdrawal symptoms, will be assessed. We will also monitor puffing intensity and real-time exposure to toxicants.

ETHICS AND DISSEMINATION

The protocol of Trial I and Trial II was approved by YSM and AUB IRBs, respectively. We will disseminate study results through peer-reviewed publications and conference presentations.

TRIAL REGISTRATION

NCT05706701 for Trial I and NCT05430334 for Trial II.

Morning Chronotype Is Associated with Improved Adherence to Continuous Positive Airway Pressure among Individuals with Obstructive Sleep Apnea

Rationale: Poor adherence limits the effectiveness of continuous positive airway pressure (CPAP) therapy for obstructive sleep apnea (OSA). A better understanding of CPAP adherence is needed to develop novel strategies to improve it. Objectives: To determine if the chronotype (morning, evening, or intermediate) of patients with OSA is associated with differences in CPAP adherence. If such an association exists, determine the mechanisms underlying this association. Methods: We performed a secondary analysis of the APPLES (Apnea Positive Pressure Long-term Efficacy Study) clinical trial. We assessed chronotype using the Morningness-Eveningness Questionnaire (MEQ) among participants randomized to the CPAP arm with daily adherence data (n = 469). Evening (MEQ ⩽ 41), intermediate (41 < MEQ < 59), and morning type (MEQ ⩾ 59) categories were the exposures. We modeled daily CPAP use (hours per night) over a 6-month period, using a linear mixed model, adjusted for covariates (e.g., age, sex, marital status). To assess mechanisms of the association, we performed mediation analyses using sleep duration, weekend catch-up sleep, depression, and other factors. Results: Most participants were obese men with severe OSA (body mass index of 32.3 ± 7.3 kg/m2, 65% male, and apnea-hypopnea index 39.8 ± 24.6/h). Participants were 44% morning, 47% intermediate, and 8% evening chronotype. Participants with the morning chronotype reported the shortest sleep duration on weekends (7.3 vs. 7.6 and 7.9 h/night) compared with the intermediate and evening types. Participants with the morning chronotype exhibited a 40-min/night higher CPAP use (P = 0.001) than persons with the intermediate chronotype. This relationship was mildly attenuated (32.8 min/night; P = 0.011) after adjustment for covariates. None of the selected factors (e.g., sleep duration, weekend catch-up sleep) exhibited a significant mediation effect. Conclusions: Morning chronotype is associated with a clinically meaningful increase in CPAP adherence compared with other chronotypes. Mechanisms of this association require further study. Chronotype may be a novel predictor of CPAP adherence. Clinical trial registered with www.clinicaltrials.gov (NCT00051363).

Dog ownership may promote cardiometabolic health in U.S. military veterans

Dog ownership has been associated with reduced cardiovascular and all-cause mortality in civilian epidemiological samples. Associations between dog ownership and cardiometabolic disease were examined in the 2019-2020 wave of the National Health and Resilience in Veterans Study. Dog and cat ownership data were obtained from 3078 Veterans and cross-tabulated with self-reported, professionally diagnosed, heart disease, heart attack, stroke, high blood pressure, diabetes, and high cholesterol. In unadjusted tests, dog ownership was associated with lower rates of heart disease, high blood pressure, diabetes, and high cholesterol, while cat ownership was not. Relative to non-owners, dog owners were younger, were more likely to screen positive for posttraumatic stress disorder and/or major depressive disorder, and more active. Binary logistic regression models of associations between dog ownership and cardiometabolic disease were adjusted for age, sex, trauma load, mood disorder, substance abuse, nicotine abuse, and exercise. After adjustment, dog ownership was still associated with lower odds of hypertension and high cholesterol. Dog ownership also interacted with exercise to lower odds of heart disease and attenuated the effect of trauma load on hypertension. Conversely, age interacted with dog ownership such that odds of diabetes and stroke were higher in older Veterans who owned dogs.

Receipt of Smoking Cessation Medications Among People With and Without Human Immunodeficiency Virus in the Veterans Aging Cohort Study (2003-2018)

Background

Nicotine replacement therapy, bupropion, and varenicline are smoking cessation medications (SCMs) shown to be similarly effective in people with and without human immunodeficiency virus (PWH and PWoH, respectively), although rates of receipt of these medications are unknown.

Methods

We identified patients in the Veterans Aging Cohort Study with electronic health record-documented current smoking using clinical reminder data for tobacco use (2003-2018). We measured receipt of SCMs using Veterans Affairs pharmacy data for outpatient prescriptions filled 0-365 days after current smoking documentation. We used log-linear, Poisson-modified regression models to evaluate the relative risk (RR) for receiving SCM by human immunodeficiency virus (HIV) status, the annual rate of receipt, and rate difference among PWH relative to PWoH.

Results

The sample included 92 632 patients (29 086 PWH), reflecting 381 637 documentations of current smoking. From 2003 to 2018, the proportion receiving SCMs increased from 15% to 34% for PWH and from 17% to 32% among PWoH. There was no statistical difference in likelihood of receiving SCM by HIV status (RR, 1.010; 95% confidence interval [CI], .994-1.026). Annual rates of receiving SCM increased for PWH by 4.3% per year (RR, 1.043; 95% CI, 1.040-1.047) and for PWoH by 3.7% per year (RR, 1.037; 95% CI, 1.036-1.038; rate difference +0.6% [RR, 1.006; 95% CI, 1.004-1.009]).

Conclusions

In a national sample of current smokers, receipt of SCM doubled over the 16-year period, and differences by HIV status were modest. However, fewer than 35% of current smokers receive SCM annually. Efforts to improve SCM receipt should continue for both groups given the known dangers of smoking.

Cholinergic system adaptations are associated with cognitive function in people recently abstinent from smoking: a (-)-[18F]flubatine PET study

The cholinergic system is a critical mediator of cognition in animals. People who smoke cigarettes exhibit cognitive deficits, especially during quit attempts. Few studies jointly examine the cholinergic system and cognition in people while trying to quit smoking. We used positron emission tomography (PET) brain imaging with the β2-subunit containing nicotinic acetylcholine receptor (β2*-nAChR) partial agonist radioligand (-)-[18F]flubatine and the acetylcholinesterase inhibitor physostigmine to jointly examine the cholinergic system, smoking status, and cognition. (-)-[18F]Flubatine scans and cognitive data were acquired from twenty people who recently stopped smoking cigarettes (aged 38 ± 11 years; 6 female, 14 male; abstinent 7 ± 1 days) and 27 people who never smoked cigarettes (aged 29 ± 8 years; 11 female, 16 male). A subset of fifteen recently abstinent smokers and 21 never smokers received a mid-scan physostigmine challenge to increase acetylcholine levels. Regional volume of distribution (VT) was estimated with equilibrium analysis at "baseline" and post-physostigmine. Participants completed a cognitive battery prior to (-)-[18F]flubatine injection and physostigmine administration assessing executive function (Groton Maze Learning test), verbal learning (International Shopping List test), and working memory (One Back test). Physostigmine significantly decreased cortical (-)-[18F]flubatine VT, consistent with increased cortical acetylcholine levels reducing the number of β2*-nAChR sites available for (-)-[18F]flubatine binding, at comparable magnitudes across groups (p values < 0.05). A larger magnitude of physostigmine-induced decrease in (-)-[18F]flubatine VT was significantly associated with worse executive function in people who recently stopped smoking (p values < 0.05). These findings underscore the role of the cholinergic system in early smoking cessation and highlight the importance of neuroscience-informed treatment strategies.

The metabotropic glutamate receptor 5 as a biomarker for psychiatric disorders

The role of glutamate system in the etiology and pathophysiology of psychiatric disorders has gained considerable attention in the past two decades, including dysregulation of the metabotropic glutamatergic receptor subtype 5 (mGlu5). Thus, mGlu5 may represent a promising therapeutic target for psychiatric conditions, particularly stress-related disorders. Here, we describe mGlu5 findings in mood disorders, anxiety, and trauma disorders, as well as substance use (specifically nicotine, cannabis, and alcohol use). We highlight insights gained from positron emission tomography (PET) studies, where possible, and discuss findings from treatment trials, when available, to explore the role of mGlu5 in these psychiatric disorders. Through the research evidence reviewed in this chapter, we make the argument that, not only is dysregulation of mGlu5 evident in numerous psychiatric disorders, potentially functioning as a disease "biomarker," the normalization of glutamate neurotransmission via changes in mGlu5 expression and/or modulation of mGlu5 signaling may be a needed component in treating some psychiatric disorders or symptoms. Finally, we hope to demonstrate the utility of PET as an important tool for investigating mGlu5 in disease mechanisms and treatment response.

Nicotine Use and Metabotropic Glutamate Receptor 5 in Individuals With Major Depressive and Posttraumatic Stress Disorders

Metabotropic glutamate receptor 5 (mGluR5) dysregulation has been implicated in the pathophysiology of many psychiatric disorders, as well as nicotine use and dependence. We used positron emission tomography with [18F]FPEB to measure mGluR5 availability in vivo in 6 groups: (1) nicotine users (NUs) without other psychiatric comorbidities (n = 23); (2) comparison controls (CCs) without nicotine use or psychiatric comorbidities (n = 38); (3) major depressive disorder subjects with concurrent nicotine use (MDD-NU; n = 19); (4) MDD subjects without concurrent nicotine use (MDD-CC; n = 20); (5) posttraumatic stress disorder subjects with concurrent nicotine use (PTSD-NU; n = 17); and (6) PTSD subjects without concurrent nicotine use (PTSD-CC; n = 16). The goal of the study was to test the hypothesis that mGluR5 availability in key corticolimbic regions of interest (ROIs) is different in NU with versus without comorbid psychiatric disorders (ROI: dorsolateral prefrontal cortex [dlPFC], orbitofrontal cortex [OFC], ventromedial prefrontal cortex [vmPFC], anterior cingulate cortex [ACC], amygdala, hippocampus). We found that NU had 11%-13% lower mGluR5 availability in OFC, vmPFC, dlPFC, and ACC as compared with CC, while PTSD-NU had 9%-11% higher mGluR5 availability in OFC, dlPFC, and ACC compared with PTSD. Furthermore, relationships between mGluR5 availability and psychiatric symptoms varied as a function of psychiatric diagnosis among NUs. NU showed a negative correlation between mGluR5 and smoking cravings and urges (r's = -0.58 to -0.70, p's = 0.011 - 0.047), while PTSD-NU had the reverse relationship (r's = 0.60-0.71, p's = 0.013-0.035 in ACC, vmPFC, and dlPFC). These findings have substantial implications for our understanding of glutamate homeostasis in psychiatric subgroups and for identifying key neural phenotypes among NU. mGluR5 is a potential treatment target for precision medicine in individuals with nicotine use.

Lower synaptic density is associated with psychiatric and cognitive alterations in obesity

Obesity is a serious medical condition that often co-occurs with stress-related psychiatric disorders. It is recognized that the brain plays a key role in the (patho)physiology of obesity and that there is a bidirectional relationship between obesity and psychopathology, yet molecular mechanisms altered in obesity have not been fully elucidated. Thus, we investigated relationships between obesity and synaptic density in vivo using the radioligand [11C]UCB-J (which binds to synaptic glycoprotein SV2A) and positron emission tomography in individuals with obesity, and with or without stress-related psychiatric disorders. Regions of interest were the dorsolateral prefrontal cortex, orbitofrontal cortex, ventromedial, amygdala, hippocampus, and cerebellum. Forty individuals with a body mass index (BMI) ≥ 25 kg/m2 (overweight/obese), with (n = 28) or without (n = 12) psychiatric diagnosis, were compared to 30 age- and sex-matched normal weight individuals (BMI < 25), with (n = 14) or without (n = 16) psychiatric diagnosis. Overall, significantly lower synaptic density was observed in overweight/obese relative to normal weight participants (ηp2 = 0.193, F = 2.35, p = 0.042). Importantly, in participants with stress-related psychiatric diagnoses, we found BMI to be negatively correlated with synaptic density in all regions of interest (p ≤ 0.03), but no such relationship observed for mentally healthy controls (p ≥ 0.68). In the stress-related psychiatric groups, dorsolateral prefrontal cortex synaptic density was negatively associated with measures of worry (r = -0.46, p = 0.01), tension/anxiety (r = -0.38, p = 0.04), fatigue (r = -0.44, p = 0.02), and attentional difficulties (r = -0.44, p = 0.02). In summary, the findings of this novel in vivo experiment suggest compounding effects of obesity and stress-related psychopathology on the brain and the associated symptomatology that may impact functioning. This offers a novel biological mechanism for the relationship between overweight/obesity and stress-related psychiatric disorders that may guide future intervention development efforts.

Recently abstinent smokers exhibit mood-associated dopamine dysfunction in the ventral striatum compared to nonsmokers: a [11C]-(+)-PHNO PET study

INTRODUCTION

Chronic nicotine exposure desensitizes dopamine responses in animals, but it is not known if this occurs in human tobacco smokers. Deficits in dopamine function are likely to make smoking cessation difficult. We used positron emission tomography (PET) brain imaging with the dopamine D2/3 receptor agonist radioligand [ 11C]-(+)-PHNO to determine if abstinent smokers exhibit less amphetamine-induced dopamine release in the ventral striatum than nonsmokers, and whether this was associated with clinical correlates of smoking cessation.

METHODS

Baseline [ 11C]-(+)-PHNO scans were acquired from smokers (n=22, 7 female, abstinent 11±9 days) and nonsmokers (n=20, 7 female). A subset of thirty-seven participants (18 smokers) received oral amphetamine (0.5 mg/kg) three hours before a second [ 11C]-(+)-PHNO scan. Binding potential (BPND) (i.e., D2/3 receptor availability) was estimated at baseline and post-amphetamine in the ventral striatum. Amphetamine-induced percent change in BPND was calculated to reflect dopamine release. Subjects also completed the Center for Epidemiologic Studies Depression Scale (CES-D).

RESULTS

There were no group differences in baseline BPND. Amphetamine-induced percent change in BPND in the ventral striatum was significantly lower in abstinent smokers compared to nonsmokers (p=0.019; d=0.82). Higher CES-D scores were significantly associated with lower ventral striatal percent change in BPND for abstinent smokers (rs=-0.627, p=0.025).

CONCLUSIONS

In conclusion, abstinent smokers exhibited significantly less amphetamine-induced dopamine release in the ventral striatum than nonsmokers. In abstinent smokers, worse mood was significantly associated with less striatal dopamine release. Our findings highlight a potential neural mechanism that may underlie negative mood symptoms during early abstinence.

IMPLICATIONS

This study combined quantitative PET imaging and an amphetamine challenge to examine striatal dopamine function during early smoking cessation attempts. The findings demonstrate that recently abstinent tobacco smokers exhibit significant, mood-associated striatal dopamine dysfunction compared to nonsmokers. This study advances our knowledge of the neurobiology underlying early quit attempts, and bridges novel neural findings with clinically relevant symptoms of smoking cessation. These results may explain the challenge of maintaining long-term abstinence from smoking, and can lend insight into the development of treatment strategies for smoking cessation.

Use and perceptions of electronic nicotine delivery systems among patients attending lung cancer screening who smoke

Given accumulating evidence that electronic nicotine delivery systems (ENDS) may be a harm-reduction alternative to combustible tobacco products, it is important to understand the real-world implications of these devices in the populations that may benefit from them the most. We surveyed the use, perceptions of, and interest in using ENDS among patients attending their initial low-dose CT scan (LDCT) for lung cancer screening (LCS) who reported current smoking, a cohort of older individuals at high-risk for lung cancer and other smoking-related illnesses due to their heavy smoking history (30 or more pack years). Participants (N = 107) completed the survey in clinic immediately before their shared decision-making visit for lung cancer screening on the day of their LDCT. Approximately a quarter of participants reported ever use of ENDS in the past; nearly a third expressed a willingness to try switching to them in the future. Prior ENDS use was significantly associated with willingness to try switching to ENDS in the future. The most common reasons to consider switching included smoking cessation and harm reduction. Only about a third were aware that ENDS are not approved by the FDA for smoking cessation; knowledge significantly varied by demographic and clinical characteristics. These findings have important implications for ENDS public health campaigns and tobacco harm reduction strategies for older individuals who smoke.

PET Imaging Estimates of Regional Acetylcholine Concentration Variation in Living Human Brain

Acetylcholine (ACh) has distinct functional roles in striatum compared with cortex, and imbalance between these systems may contribute to neuropsychiatric disease. Preclinical studies indicate markedly higher ACh concentrations in the striatum. The goal of this work was to leverage positron emission tomography (PET) imaging estimates of drug occupancy at cholinergic receptors to explore ACh variation across the human brain, because these measures can be influenced by competition with endogenous neurotransmitter. PET scans were analyzed from healthy human volunteers (n = 4) and nonhuman primates (n = 2) scanned with the M1-selective radiotracer [11C]LSN3172176 in the presence of muscarinic antagonist scopolamine, and human volunteers (n = 10) scanned with the α4β2* nicotinic ligand (-)-[18F]flubatine during nicotine challenge. In all cases, occupancy estimates within striatal regions were consistently lower (M1/scopolamine human scans, 31 ± 3.4% occupancy in striatum, 43 ± 2.9% in extrastriatal regions, p = 0.0094; nonhuman primate scans, 42 ± 26% vs. 69 ± 28%, p < 0.0001; α4β2*/nicotine scans, 67 ± 15% vs. 74 ± 16%, p = 0.0065), indicating higher striatal ACh concentration. Subject-level measures of these concentration differences were estimated, and whole-brain images of regional ACh concentration gradients were generated. These results constitute the first in vivo estimates of regional variation in ACh concentration in the living brain and offer a novel experimental method to assess potential ACh imbalances in clinical populations.

Clearing the Haze: What Do We Still Need to Learn about Electronic Nicotine Delivery Systems?

Electronic nicotine delivery systems (ENDS; i.e., electronic cigarettes, e-cigarettes, vaping devices, vape pens) were introduced to the U.S. market in 2007 as a potential harm reduction alternative for people who smoked combustible cigarettes. Since that time, ENDS popularity grew very quickly, particularly among individuals who smoke cigarettes. However, young people and never smokers also started using ENDS, cohorts for whom these products were not intended. There are now a broad range of devices and e-liquid constituents. ENDS devices vary considerably in their design and generation of potentially toxic chemicals, with higher power devices likely much more hazardous than lower power devices. This landscape may further change after September 9, 2020, when all ENDS manufacturers are required to submit a premarket tobacco product application to the FDA to obtain authorization for marketing. Research has not kept pace with this rapidly changing technology and important questions remain regarding the relative benefits versus risks of ENDS. In light of these challenges, we propose key ENDS research priorities to address these gaps.

Marijuana Vaping in U.S. Adults: Evidence From the Behavioral Risk Factor Surveillance System

INTRODUCTION

As of February 18, 2020, states have reported 2,807 cases of e-cigarette, or vaping, product use-associated lung injury to the Centers for Disease Control and Prevention. Most cases involved cannabinoids. This study identifies current risk factors for adult marijuana vaping by analyzing 2017 and 2018 Behavioral Risk Factor Surveillance System data.

METHODS

Data on 8,255 people who recently used marijuana were analyzed in September 2019. Sample-weighted multivariate logistic regressions considered a binary indicator for vaping as the primary method of marijuana use. Adjusting for demographic controls, regressions assessed the association between marijuana vaping and marijuana use for medical purposes (versus nonmedical only), current conventional cigarette use, current nicotine e-cigarette use, and 2 mental health variables. Demographic controls were binary indicators for female sex, Hispanic ethnicity, race, and having completed ≥1 year of college.

RESULTS

Odds of marijuana vaping were higher among those who reported using for medical purposes (AOR_{age18-24years}=3.8, 95% CI=1.91, 7.67; AOR_{age25-54years}=1.8, 95% CI=1.02, 3.08; AOR_{age55-64years}=2.3, 95% CI=0.75, 7.07) and lower among people who smoked combustible cigarettes (AOR_{age18-24years}=0.2, 95% CI=0.06, 0.65; AOR_{age25-54years}=0.2, 95% CI=0.10, 0.26; AOR_{age55-64years}=0.1, 95% CI=0.05, 0.34). Vaping nicotine e-cigarettes was associated with greater odds of vaping marijuana for adults aged 25-54 years (AOR=4.6, 95% CI=2.70, 7.78) but not those aged 18-24 years (AOR=0.9, 95% CI=0.33, 2.26).

CONCLUSIONS

Among people who use marijuana, adults reporting medical marijuana use were more likely to vape as their primary mode of consumption, whereas conventional cigarette smokers were less likely to do so. Use of nicotine e-cigarettes was associated with a greater likelihood of vaping marijuana for adults aged 25-54 years.

Inverse changes in raphe and cortical 5-HT1B receptor availability after acute tryptophan depletion in healthy human subjects

Serotonergic neurotransmission plays a key role in the pathophysiology and treatment of various neuropsychiatric diseases. The purpose of this study was to investigate changes in serotonergic neurotransmission after acute tryptophan depletion (ATD) using positron emission tomography (PET) with [¹¹ C]P943, a 5-HT_1B receptor radioligand previously shown to be sensitive to changes in 5-HT. Five healthy subjects were scanned on a high resolution PET scanner twice on the same day, before and approximately 5 hours after ingesting capsules containing an amino acid mixture that lacks tryptophan. For each scan, emission data were acquired for 120 min after intravenous bolus injection of [¹¹ C]P943. Binding potential (BP_ND ) values were estimated from parametric images using the second version of the multilinear reference tissue model (MRTM2, t* = 20 min) with cerebellar grey matter used as a reference region. The change in [¹¹ C]P943 binding (ΔBP_ND , %) was calculated as (BP_ND,post  - BP_ND,pre )/(BP_ND,pre ) × 100, and correlation analysis was performed to measure linear associations of ΔBP_ND between raphe and other regions of interest (ROIs). ΔBP_ND ranged from -6% to 45% in the raphe, with positive values indicating reduced competition from 5-HT. In cortical regions, ΔBP_ND ranged from -28% to 7%. While these changes did not reach significance, there were significant negative correlations of ΔBP_ND of the raphe with those of cerebral cortical regions and the thalamus (e.g., r = -.96, p = .011 for average cortex). These findings support the hypothesis that raphe serotonin is a critical modulator of cortical serotonin release via projecting neurons in healthy human subjects.

Nicotine Dependence in US Military Veterans: Results from the National Health and Resilience in Veterans Study

BACKGROUND

Veterans are a unique population that may be at increased risk of tobacco use disorder and nicotine dependence (ND). We analyzed data from the National Health and Resilience in Veterans Study (NHRVS), a large nationally representative sample of US veterans, in order to more fully understand the prevalence and correlates of lifetime ND in US Veterans.

METHODS

Descriptive statistics were conducted to summarize health and functioning/quality of life characteristics among veterans with and without lifetime ND. Hierarchical binary logistic regression analyses were conducted to evaluate the relationship between ND and psychiatric and physical health variables.

RESULTS

Compared with veterans without lifetime ND, veterans with lifetime ND were more likely to screen positive for several lifetime psychiatric disorders including current alcohol use disorder (odds ratio [OR] 2.79 [95% confidence interval [CI] 2.23, 3.49]), depression (OR 1.86 [1.38, 2.50]), and PTSD (OR 1.68 [1.14, 2.47]). From a medical standpoint, they were more likely to endorse having kidney disease (OR 4.18 [2.55, 6.86]), heart attack (OR 2.09 [1.51, 2.89]), and rheumatoid arthritis (1.90 [1.20, 3.00]) in addition to other conditions. They scored lower in overall physical functioning and higher in somatization symptoms.

CONCLUSIONS

Veterans with lifetime ND in the NHRVS survey were more likely to have psychiatric and medical conditions and lower physical functioning compared with Veterans without lifetime ND. Veterans with lifetime ND may therefore require a comprehensive and integrated approach to care that includes attention to co-morbid illness in addition to drug addiction.

Electronic cigarette and tobacco use in individuals entering methadone or buprenorphine treatment

BACKGROUND

Although smoking is prevalent among populations with opioid use disorder (OUD), few studies have examined electronic cigarette (EC) use in individuals seeking opioid agonist therapy (OAT). The aim of this study was to evaluate the prevalence and correlates of EC use among individuals seeking OAT.

METHODS

782 patients seeking OAT for OUD completed surveys assessing current and past EC use, reasons for use, current and past cigarette smoking, nicotine dependence, psychiatric distress, trauma, and pain. Bivariate and multivariate models evaluated correlates of daily EC use, past-30-day EC use, and current cigarette smoking.

RESULTS

6% of patients reported daily EC use, 18% reported past-30-day use, 62% reported EC use history, and 85% reported current cigarette smoking. 46% reported using ECs to quit or cut down smoking. In multivariate analyses, daily EC use was associated with higher odds of being a former smoker (OR 21; CI 1.7-273) and lower odds of ever smoking more than 100 cigarettes (OR 0.07; CI 0.01-0.32), while EC use in the past 30 days was associated with lower odds of being Caucasian (OR 0.55; CI 0.34-0.89), ever smoking more than 100 cigarettes (OR 0.13; CI 0.02-0.67), and history of chronic pain (OR 0.59; CI 0.38-0.90), and higher odds of reporting psychiatric distress (OR 1.5; CI 1.1-2.2).

CONCLUSIONS

EC use is common among people with OUD who smoke cigarettes. Those with daily use had higher odds of being former smokers than current smokers. Interventions using ECs may be effective to help reduce harms and mortality in OUD.

Debating Medical Utility, Not Futility: Ethical Dilemmas in Treating Critically Ill People Who Use Injection Drugs

Physicians who care for critically ill people with opioid use disorder frequently face medical, legal, and ethical questions related to the provision of life-saving medical care. We examine a complex medical case that illustrates these challenges in a person with relapsing injection drug use. We focus on a specific question: Is futility an appropriate and useful standard by which to determine provision of life-saving care to such individuals? If so, how should such determinations be made? If not, what alternative decisionmaking framework exists? We determine that although futility has been historically utilized as a justification for withholding care in certain settings, it is not a useful standard to apply in cases involving people who use injection drugs for non-medical purposes. Instead, we are welladvised to explore each patient's situation in a holistic approach that includes the patient, family members, and care providers in the decision-making process. The scope of the problem illustrated demonstrates the urgent need to definitively improve outcomes in people who use injection drugs. Increasing access to high quality medication-assisted treatment and psychiatric care for individuals with opioid use disorder will help our patients achieve a sustained remission and allow us to reach this goal.

Electronic cigarettes for adults with tobacco dependence enrolled in a tobacco treatment program: A pilot study

INTRODUCTION

Electronic cigarettes (ECs) have emerged as a potential harm-reducing alternative for tobacco smokers. However, the role ECs might play in treatment settings is unclear. We conducted an exploratory study of treatment-seeking smokers enrolling in a standard tobacco treatment program who were provided with either a nicotine or non-nicotine EC to use as needed to cease tobacco smoking.

METHODS

Treatment-seeking smokers received standard tobacco treatment for 8weeks and were given nicotine transdermal patch therapy, behavioral counseling, and either a nicotine or non-nicotine EC to use as needed. Smoking and EC use patterns were tracked longitudinally to week 24.

RESULTS

40 subjects were enrolled into the study. At week 24, 6 subjects (15%) were abstinent, and the mean reduction in reported cigarettes smoked per day was 6.8±12. There were no significant differences in smoking outcomes between those who received a nicotine or non-nicotine EC (proportion abstinent at 24weeks: nicotine EC=4/20 (20%); non-nicotine EC=2/20 (10%); p=0.66). Among subjects assessed at follow-up, 62.5% were EC non-users.

CONCLUSIONS

The addition of a 2nd generation EC to outpatient tobacco treatment among tobacco smokers is feasible. Among those who quit smoking, half were still using the EC at 6-month follow-up. Appeal of the EC among smokers was variable, and those who had quit smoking tended to switch to lower strength nicotine solutions. Further research is needed to determine whether ECs can reduce harm and be an effective adjunct to existing tobacco treatment interventions.

Use of Electronic Cigarettes Leads to Significant Beta2-Nicotinic Acetylcholine Receptor Occupancy: Evidence From a PET Imaging Study

Background

Electronic cigarettes (ECs) can influence nicotine addiction by delivering aerosolized nicotine. We investigated if nicotine from ECs is delivered to the brain β2*-nicotinic acetylcholine receptors (β2*-nAChR) and how this relates to the behavioral effects and nicotine delivery from cigarettes.

Methods

Seven nicotine users participated in positron emission tomography (PET) studies with (-)-[18F]Flubatine before and after nicotine challenge with 0, 8, and 36 mg/ml nicotine in a 3.3 Volt, 1.5 Ohm EC or a standard tobacco cigarette. Craving was evaluated before and after product use.

Results

Average β2*-nAChR occupancy was higher after 36 mg/ml EC challenge compared to 8 mg/ml EC at trend level. Average β2*-nAChR occupancy after tobacco cigarette smoking was 68 ± 18% and was not different compared with 8 mg/ml (64 ± 17%,) or 36 mg/ml (84 ± 3%) nicotine in EC users. Area under the curve (AUC) of blood nicotine level was higher in the cigarette smoking group compared with the 8mg/ml group (p = 0.03), but similar compared with the 36 mg/ml EC (p = 0.29). Drug craving was reduced after use of the tobacco cigarette, 8 mg/ml EC, and 36 mg/ml EC.

Conclusions

In this novel investigation of EC effects at β2*-nAChRs, we show that average β2*-nAChR occupancy was higher after 36 mg/ml EC challenge compared with 8 mg/ml EC. Receptor occupancy and arterial blood nicotine levels after cigarette smoking were similar to 36 mg/ml EC use under controlled conditions. These findings suggest that the ECs studied here have abuse liability and may provide an adequate alternative nicotine delivery system for cigarette smokers.

Implications

This is the first study to directly determine the neurologic effects of electronic cigarettes on human brain beta-2 nicotinic acetylcholine receptors using PET neuroimaging with (-)-[18F]Flubatine, a novel radiotracer. Our findings suggest that the e-cigarettes studied here have abuse liability and may provide an adequate alternative nicotine delivery system for cigarette smokers.

A Comprehensive Approach to Tobacco Dependence Interventions

Tobacco smoking remains the leading preventable cause of death and illness in the United States. Smoking cessation is particularly relevant for individuals with chronic obstructive pulmonary disease because it is known from multiple studies that individuals who quit smoking experience an initial improvement in pulmonary function, a decreased rate of normal age-related decline in FEV1, a lower risk of hospital admission, and improved survival. Tobacco dependence must be recognized as a chronic disease, and comprehensive treatment for the tobacco-dependent patient with chronic obstructive pulmonary disease begins with a physician's inquiry into smoking and encouragement to quit, followed by an assessment of the level of dependence and the severity of withdrawal symptoms during previous quit attempts. Combination pharmacotherapy is recommended for the initial treatment of most smokers, especially those with moderate to high baseline levels of tobacco dependence. The patient's history, combined with his or her personal preference, can guide the clinician in initiating an appropriate treatment regimen. Given the chronic nature of tobacco dependence, clinicians must anticipate relapses and the need for recurrent, long-term follow-up. Comprehensive tobacco treatment consultation should be sought whenever possible for patients with high levels of tobacco dependence and multiple relapses or failed quit attempts.