Twenty-Four-Hour Cardiovascular Effects of Electronic Cigarettes Compared With Cigarette Smoking in Dual Users.

Background Cardiovascular safety is an important consideration regarding the benefits versus risks of electronic cigarette use (EC) for public health. The single-use cardiovascular effects of EC have been well studied but may not reflect effects of ad libitum use throughout the day. We aimed to compare the circadian hemodynamic effects as well as 24-hour biomarkers of oxidative stress, and platelet aggregation and inflammation, with ad libitum cigarette smoking (CS) versus EC versus no tobacco product use. Methods and Results Thirty-six healthy dual CS and EC users participated in a crossover study in a confined research setting. Circadian heart rate, blood pressure and plasma nicotine levels, 24-hour urinary catecholamines, 8-isoprostane and 11-dehydro-thromboxane B2, and plasma interleukin-6 and interleukin-8 were compared in CS, EC, and no nicotine conditions. Over 24 hours, and during daytime, heart rate and blood pressure were higher in CS and EC compared with no tobacco product conditions (P<0.01). Heart rate on average was higher with CS versus EC. Urinary catecholamines, 8-isoprostane, and 11-dehydro-thromboxane B2 were not significantly different, but plasma IL-6 and IL-8 were higher with both CS and EC compared with no tobacco product (P<0.01). Conclusions CS and EC had similar 24-hour patterns of hemodynamic effects compared with no tobacco product, with a higher average heart rate with CS versus EC, and similar effects on biomarkers of inflammation. EC may pose some cardiovascular risk, particularly to smokers with underlying cardiovascular disease, but may also provide a harm reduction opportunity for smokers willing to switch entirely to EC. Registration URL: https://www.clinicaltrials.gov; Unique Identifier: NCT02470754.

Characterization of Nicotine Salts in 23 Electronic Cigarette Refill Liquids.

INTRODUCTION: Many electronic cigarette manufacturers have begun offering liquids containing "nicotine salts," which are formed when an acid is mixed in a solution with free-base nicotine. Type of salt could play a significant role in the abuse liability of electronic cigarette liquids. As a first step to understanding nicotine salts, this study sought to identify the types of acids present in 23 commercially available electronic cigarette liquids. AIMS AND METHODS: Twenty-three electronic cigarette liquids advertised as containing nicotine salts were purchased for analysis. These liquids were tested for the presence of 11 different organic acids that were deemed likely to be used in a nicotine salt formulation. Liquids were analyzed using a combination of liquid chromatography-mass spectrometry and gas chromatography-mass spectrometry methods, then compared to authentic acid standards for identification. RESULTS: Six of the 11 possible acids were identified in the liquids, from most to least common: lactic, benzoic, levulinic, salicyclic, malic, and tartaric acid. Acid(s) could not be identified in one of the liquids. Though most liquids contained only one type, three of the liquids contained multiple acids. CONCLUSIONS: These data demonstrate that several types of salts/acids are currently being used in electronic cigarette liquids. The type and concentration of salt(s) used in these liquids may differentially alter sensations in the throat and upper airway, and overall pharmacology of the aerosols by altering liquid pH and from flavor and sensory characteristics of the acids themselves. IMPLICATIONS: This study demonstrates that at least six different types of acids are being used to create the nicotine salts in electronic cigarette liquids, with the acids lactic, benzoic, and levulinic being the most frequently identified. Identification of these acids can serve as the foundation for future research to determine if type of nicotine salt alters pharmacological and toxicological effects of electronic cigarettes.

Twenty-four-hour subjective and pharmacological effects of ad-libitum electronic and combustible cigarette use among dual users.

BACKGROUND AND AIMS: Relative pharmacological effects of e-cigarettes and cigarettes during 24 hours of ad-libitum use have not been described. In this study, 24-hour blood plasma nicotine concentrations and 48-hour subjective effects with use of cigarettes and e-cigarettes were measured among dual users. DESIGN: Two-arm within-subject cross-over design with preferred e-cigarette or cigarette ad-libitum use over 48 hours. SETTING: Hospital research ward in San Francisco, California, USA. PARTICIPANTS: Thirty-six healthy dual users of e-cigarettes and cigarettes (n = 8, 25% females). MEASUREMENTS: Twenty-four-hour blood plasma nicotine and cotinine concentrations and 48-hour self-reported nicotine withdrawal symptoms and rewarding effects. FINDINGS: Analyses used analysis of variance (ANOVA)-based mixed models with order of product (e-cigarette or cigarette) and product type (combustible cigarette or type of e-cigarette) as fixed effects, and subject as a repeated effect. During a 24-hour period, e-cigarettes produced lower nicotine exposure than cigarettes for the majority of users, although 25% received more nicotine from e-cigarettes, which was predicted by more frequent e-cigarette use or greater dependence. Compared to cigarette smoking, nicotine exposure for variable-power tank users was similar, while cig-a-like (t(30)  = 2.71, P = 0.011, d = 0.745) and fixed-power tank users (t(30)  = 3.37, P = 0.002, d = 0.993) were exposed to less nicotine. Cigarettes were rated higher than e-cigarettes on some desirable subjective effects (e.g. psychological reward, t(322)  = 7.24 P < 0.001, d = 0.432), but withdrawal symptom reduction was comparable. No differences were found between e-cigarette types, but Bayes factors indicate that these measures were insensitive. CONCLUSIONS: During a 24-hour period in a hospital setting in the United States, nicotine exposure for dual users of e-cigarettes and cigarettes was similar when using cigarettes or variable-power tank devices only but was lower for those using cig-a-like or fixed-power devices only. Despite lower nicotine levels, all types of e-cigarette were effective in preventing withdrawal symptoms. E-cigarettes were rated less rewarding than cigarettes.

Dimensions of impulsive behavior: Predicting contingency management treatment outcomes for adolescent smokers.

BACKGROUND: Behavioral measures of impulsive behavior include the dimensions of behavioral disinhibition, decision-making, and lapses of attention. These behaviors are associated with a range of risky activities during adolescence, including cigarette smoking; however, few studies have evaluated their associations with tobacco treatment outcomes. The current study examined the relationship between impulsive behavior and contingency management treatment outcomes for adolescent smokers. METHODS: Data from two contingency management smoking cessation trials were combined (N = 189 adolescents). Participants provided breath carbon monoxide (CO) samples with incentives delivered contingent (i.e., active treatment [AT] condition) or non-contingent (i.e., control treatment [CT] condition) on CO level. Dimensions of impulsive behavior were assessed pre- and post-treatment using the Go/Stop Task, a measure of delay discounting, a continuous performance task, while self-reported impulsivity was assessed with the Barratt Impulsiveness Scale-Adolescent. Relationships between impulsive behavior and treatment outcomes (efficacy and adherence) were assessed using linear mixed effects models. RESULTS: Participants in the AT condition had significantly lower program CO levels at each treatment phase. Delay discounting in the AT condition predicted CO levels, with those discounting the most lowering their breath CO levels the least. Delay discounting also predicted program adherence across both conditions. CONCLUSIONS: Delay discounting may be the most relevant dimension of impulsive behavior to predict outcomes for adolescent smokers completing CM programs, both in terms of successful reductions in smoking and program adherence. Suggestions are made to reduce the effects of delay discounting for adolescent smokers using this treatment approach.

Electronic cigarette liquid and device parameters and aerosol characteristics: A survey of regular users.

INTRODUCTION: Electronic cigarettes are widely variable devices, typically with user definable liquid and device parameters. Yet, little is known about how regular users manipulate these parameters. There is also limited understanding of what factors drive electronic cigarette use and liquid purchasing, and whether two common ingredients, propylene glycol and vegetable glycerin, alter the subjective effects of these devices. METHODS: During the spring of 2016 522 adults, who reported daily use of electronic cigarettes containing nicotine, completed a survey on electronic cigarettes. Survey questions included an electronic cigarette dependence questionnaire, questions on tobacco and electronic cigarette use, and device and liquid preferences. RESULTS: Fifty-nine percent of respondents reported using another tobacco product, which was positively associated with level of nicotine dependence. On average, devices were set to 28.3 (SD = 24.2) watts. Ability to change device voltage, and level of resistance typically used, was significantly associated with level of nicotine dependence. Amount of liquid consumed, nicotine concentration, and milligrams of nicotine used per week, were positively associated with nicotine dependence. Participants rated 'good taste' as the most important consideration when using and purchasing liquids, and propylene glycol is associated with undesirable effects and vegetable glycerin with desirable effects. CONCLUSIONS: These data indicate that electronic cigarette users utilize a wide range device parameter settings and liquid variables, and that individuals with greater nicotine dependence favor voltage control devices, and lower resistance heating elements. Taste is a key factor for electronic cigarette selection, and concentrations of propylene glycol and vegetable glycerin may have a significant impact on the reinforcing effects of liquids.

A Prototypical First-Generation Electronic Cigarette Does Not Reduce Reports of Tobacco Urges or Withdrawal Symptoms among Cigarette Smokers.

It is unknown whether first-generation electronic cigarettes reduce smoking urges and withdrawal symptoms following a 24 h deprivation period. This study tested whether a first-generation electronic cigarette reduces smoking urges and withdrawal symptoms in cigarette smokers. Following 24 h of tobacco deprivation, using a within-subjects design, eight nontreatment seeking tobacco cigarette smokers (3 females) administered 10 puffs from a conventional cigarette or a first-generation electronic cigarette containing liquid with 0, 8 or 16 mg/ml nicotine. Conventional cigarettes ameliorated smoking urges and electronic cigarettes did not, regardless of nicotine concentration. First-generation electronic cigarettes may not effectively substitute for conventional cigarettes in reducing smoking urges, regardless of nicotine concentration.

The effect of self-regulated caffeine use on cognition in young adults.

OBJECTIVE: Based on previous observational studies that have suggested self-regulated caffeine use by older adults may enhance reaction time performance and vigilance on cognitive tasks, the current study sought to examine whether this effect held true for young adults as well. METHODS: One hundred and four young adults from two major metropolitan areas, ages 18-29 years, not meeting the criteria for a current psychiatric disorder, completed several cognitive tasks related to decision-making (Cambridge Gamble Task), response inhibition and reaction time (stop-signal task), and vigilance and reaction time (Rapid Visual Information Processing). Caffeine usage was self-reported using a reliable quantity and frequency questionnaire. RESULTS: Self-reported caffeine usage was not significantly associated with any of the cognitive measures used in this study after controlling for age, gender, cigarette smoking, alcohol use, cannabis use, and gambling frequency. CONCLUSIONS: These data suggest that self-regulated caffeine usage may not have a significant impact on reaction time, vigilance, response inhibition, or decision-making in young adults, or that these effects are contingent upon other variables not accounted for in the current study.

Sleepiness and cognition in young adults who gamble and use alcohol.

BACKGROUND AND AIMS: Past research suggests that sleep problems are associated with increased risky decision-making. Similarly, gambling disorder and alcohol use disorder are also associated with increased risky decision-making. Individuals with gambling disorder or alcohol use disorder have also reported higher rates of sleep problems compared to normal healthy controls. As such, we sought to examine whether sleep problems play a role in the development of alcohol use disorder or gambling disorder. METHODS: One hundred and forty-one individuals who gamble and use alcohol, yet do not meet criteria for gambling disorder or alcohol use disorder, were assessed to determine the correlation between sleepiness, amount of sleep obtained, decision-making, and alcohol or gambling behaviors. RESULTS: Our results suggest that inconsistent sleep patterns may be associated with increased frequency of alcohol use and gambling. We did not, however, find a significant correlation between sleep factors and decision-making. DISCUSSION: Further research is needed to examine the specific relationship between sleep patterns and alcohol use and gambling frequency. Overall these data suggest that sleepiness or sleep and risky decision-making is not a significant factor in gambling and alcohol use behaviors in individuals not meeting criteria for alcohol use disorder or gambling disorder.

Prediction of alcohol and gambling problems in young adults by using a measure of decision making.

OBJECTIVES: Individuals who regularly gamble, regularly consume alcohol, or meet criteria for an alcohol-use disorder or pathological gambling may make riskier decisions on cognitive tasks. What remains unclear in the literature is whether these decision-making deficits precede or result from these addictive behaviors. This study aimed to determine whether risky decision making on a cognitive task is predictive of increasing gambling behaviors and alcohol use. METHODS: Fifty-eight young adults (aged 18-29 years) free from Axis I disorders and reporting no symptoms of at-risk gambling behavior or alcohol consumption, who were participating in a longitudinal study of impulsivity, were grouped as either high-risk decision makers (n = 29) or low-risk decision makers (n = 29) by using the Cambridge Gamble Task. Subjects were assessed at 1-year follow-up to examine gambling frequency, alcohol consumption, at-risk alcohol-use criteria, alcohol-use disorder criteria, at-risk gambling criteria, and pathological gambling criteria. RESULTS: High-risk decision makers were found to be more likely to meet at-risk criteria for alcohol use after 1 year. Decision-making group membership was not significantly correlated with frequency of gambling or development of pathological gambling or alcohol-use disorder over 1 year. CONCLUSIONS: A variable measuring risky decision making on the Cambridge Gambling Task may be able to predict who is more likely to increase alcohol use per session later in life.

Age at onset in trichotillomania:clinical variables and neurocognitive performance.

OBJECTIVE: Trichotillomania (TTM), or compulsive hair pulling, is a common psychiatric disorder characterized by psychosocial impairment and reduced quality of life. The aim of this retrospective study was to characterize the impact of age at TTM onset on clinical variables and neuropsychological function using a variety of clinical and neurocognitive measures. METHOD: The study sample included 98 adult treatment-seeking individuals with a DSM-IV diagnosis of TTM. Correlates were explored by grouping participants into childhood-onset (onset at ≤ 11 years old, n = 42) or later-onset (≥ 12 years old, n = 56) TTM and via linear regression. All subjects underwent a semistructured clinical interview with a psychiatrist and completed a variety of paper-pencil tests regarding TTM severity and quality of life. A subset (n = 44) of subjects underwent neurocognitive testing assessing motor inhibition and set-shifting compared to a sample (n = 27) of age- and gender-matched healthy controls. Data were collected from September 2006 through July 2011. RESULTS: Postpubertal age at onset was significantly associated with greater TTM symptom severity. Clinically, the later-onset group pulled their hair for a significantly greater amount of time daily (P = .008), had higher clinician-rated TTM severity on the Clinical Global Impressions-Severity of Illness scale (P = .042), and had higher patient-rated severity on the Massachusetts General Hospital Hairpulling Scale (P = .022) compared to healthy controls. On the neurocognitive tasks, later-onset TTM was characterized by stop-signal impairments (P = .020) and relatively spared set-shifting, consistent with previous studies in the literature. In contrast, the childhood-onset manifestation was associated with set-shifting deficits in stages of the task completed and total errors adjusted (both P < .001) but relatively spared stop-signal performance compared to healthy controls. CONCLUSION: Results indicate that childhood-onset of TTM is common, as confirmed by the fact that 42.9% of our sample met childhood-onset criteria, and may differ neurobiologically from the prototypical later-onset form. Future neurobiological and treatment studies should measure age at onset and explore further these putative differences.Trial Registration ClinicalTrials.gov identifiers: NCT00354770 and NCT00775229.

Cognitive task performance and frequency of alcohol usage in young adults.

OBJECTIVES: The goal of our study was to examine cognitive effects of alcohol in young adults at varied levels of alcohol usage using well-validated computerized cognitive measures. METHODS: One hundred fifty-five young adults (mean age: 21.15 ± 3.092 years; 25.8% female), free from non-alcohol-related psychiatric diagnoses and drug use, underwent selected tests from the Cambridge Neuropsychological Test Automated Battery in conjunction with the Barratt Impulsivity Scale, Eysenck Impulsivity Questionnaire, and the Tridimensional Personality Questionnaire. Study participants were grouped according to alcohol frequency: nondrinkers, at-risk drinkers (subsyndromal alcohol usage), and alcohol use disorder. RESULTS: At-risk drinkers and individuals with alcohol use disorders bet significantly more overall on the Cambridge Gambling Task than nondrinkers. There were no significant differences noted between groups on the Spatial Working Memory task or Intra-dimensional/Extra-dimensional Set Shift task. Individuals with alcohol use disorders endorsed higher impulsivity than at-risk and nondrinkers on the Barratt Impulsivity Scale and Eysenck Impulsivity Questionnaire. Individuals with alcohol use disorders and at-risk drinkers also endorsed higher venturesomeness than nondrinkers on the Tridimensional Personality Questionnaire. CONCLUSIONS: Results from the Cambridge Gambling Task suggest that even at a subsyndromal level, young adults make risky decisions that mirror those seen in individuals with alcohol use disorders.