E-cigarette- specific symptoms of nicotine dependence among Texas adolescents

IntroductionThe potential of e-cigarettes to elicit symptoms of nicotine dependence has not been adequately studied, particularly in adolescent populations. The present study examined the prevalence of e-cigarette-specific symptoms of nicotine dependence (“symptoms of e-cigarette dependence”) and the associations between these symptoms, e-cigarette usage group, and e-cigarette cessation-related items among Texas adolescents.MethodsThis study involved a cross-sectional analysis of adolescents from Wave 4 of the Texas Adolescent Tobacco and Marketing Surveillance System (TATAMS) (n = 2891/N = 461,069). Chi-Square analyses examined differences in the prevalence of symptoms of dependence by e-cigarette usage group (exclusive versus dual users of e-cigarettes and combustible tobacco products) and demographic characteristics. Weighted multivariable logistic regression analyses examined the associations between symptoms of e-cigarette dependence, e-cigarette usage group, and e-cigarette cessation items.ResultsExclusive e-cigarette users experienced symptoms of e-cigarette dependence, although the prevalence of most of the symptoms was higher for dual users. Adolescents who reported more symptoms of dependence were less likely to report both wanting to quit e-cigarettes and a past-year quit attempt for e-cigarettes (adjusted odds ratio “AOR” = 0.61 (95% CI = 0.41, 0.92) and AOR = 0.52 (95% CI = 0.30, 0.92), respectively).ConclusionsThis study is the first to demonstrate that adolescent e-cigarette users are experiencing symptoms of dependence specific to e-cigarettes. In addition, symptoms of dependence may be barriers to e-cigarette cessation. Future research is needed to determine if characteristics of e-cigarette use (e.g. frequency and intensity) are associated with dependence.     

Using qualitative research to inform survey development on nicotine dependence among adolescents

Researchers interested in measuring tobacco use and dependence among youth face several formidable challenges. These challenges include: most existing measures have been developed for adult samples and may not be suitable for adolescent respondents; surveys must be relevant to different youth subcultures and to both genders; questions must be developmentally appropriate and not perceived as judgmental or condescending; and the multidimensional nature of nicotine dependence in youth must be recognized and measured. This paper demonstrates how researchers can address these challenges by using qualitative techniques to obtain information on youth tobacco consumption, and then using this information to inform the development of quantitative instruments. A case study is presented where a measure of tobacco dependence originally developed for adults is adapted for use with adolescents. A seven-step formative research process is outlined, consisting of gathering information in open-ended interviews, conducting follow-up research, modification of questionnaire items and addition of new items based on the information gathered, constructing a reliable instrument that is readable and acceptable to youth, reducing the length of this instrument without significantly hurting reliability and validity, conducting additional follow-up research involving case studies, and examining cultural differences. Following a formative research process like this one will help tobacco researchers gain a better understanding of how nicotine dependence develops.     

Trait anxiety and nicotine dependence in adolescents: a report from the DANDY study

The Revised Children's Manifest Anxiety Scale (RCMAS) and the Hooked on Nicotine Checklist (HONC) were used to measure trait anxiety and tobacco dependence in a population of 581 adolescents. Smokers demonstrated higher mean RCMAS scores (9.3, S.D.=6.5) than nonsmokers did (7.4, S.D.=6.2, t=-3.7, P<.001). Participants with symptoms of tobacco dependence had higher RCMAS scores (mean=11.6, S.D.=6.0, n=115) than did the participants without symptoms (mean=7.8, S.D.=6.0, n=177, t=-5.3, P<.001). Scores on the RCMAS and the HONC correlated positively (n=292, r=.32, P<.001). Participants who had felt relaxed in response to their first exposure to nicotine were also more likely to develop dependence and to report that stress caused cravings or a need to smoke. Trait anxiety and relaxation in response to the first dose of nicotine were unrelated and appear to be independent risk factors for the development of nicotine dependence and a reliance on tobacco to cope with stress.     

Pharmacotherapy of nicotine dependence

Withdrawal treatment of cigarette smokers is a task of the utmost urgency in view of the consequences for national health programs and legislative policies of the high morbidity and mortality rates caused by smoking. Smokers need medical consultation in addition to drug-based treatment, but this results in self-willed quitting of the smoking habit in a limited number of smokers only. From the point of view of the criteria of "evidence-based medicine", non-drug methods such as hypnosis therapy and acupuncture are not effective (odds ratio = 1.22). Among the drug-based methods, treatment with nicotine substitution preparations has shown confirmed efficacy in numerous studies (odds ratio 1.63 to 2.67, depending on the application form used) and results in successful withdrawal from the smoking habit in 30-40% of cases. A decisive problem in the initial therapeutic phase appears to be the amount of the applied nicotine dose, but beyond that can be mastered above all by combining 2 or 3 application forms (patchs, chewing gum, nasal spray). Treatment is then continued for 4-12 weeks, depending on the degree of dependence, with successively reduced nicotine dosage. Two controlled studies with disparate designs have been done on bupropion (odds ratio 2.3/3.0). However, further studies are desirable due to concern about undesirable effects of bupropion described recently. Other substances subjected to trials in years past, such as clonidine, lobeline, mecamylamine and antidepressants including buspirone cannot be recommended on the basis of current data for treatment of smokers seeking a withdrawal cure.     

尼古丁依赖的药物治疗

烟草是世界上使用最普遍的精神活性物质。烟草中的成分复杂 ,其种类高达２０００多［１］，但只有尼古丁象其它依赖性药物如海洛因、可卡因等一样，可以在人和动物中引起耐受、依赖及戒断综合征［２］，象其它精神活性物质一样，尼古丁依赖的核心特征也是难以克制的觅药和用药     

酒依赖和烟草依赖共病的研究进展

酒精和烟草在大多数国家是不受管制的精神活性物质,与阿片类和可卡因等"硬"毒品不同,它们仅被限制使用(成年人才有资格得到它)而并未被社会禁止.因此,它们被不同国家、不同文化背景的人群广泛使用,酒依赖和烟草依赖也就成了最常见的物质使用障碍并导致了大量的医学和社会问题.许多研究显示,一种成瘾物质的使用会增加其他成瘾物质的使用风险,更有许多研究显示,吸烟和饮酒之间有阳性关联.本文就酒依赖和烟草依赖之间的关联特征和可能机制作一综述.     

Genetics of nicotine dependence and pharmacotherapy

Nicotine dependence is substantially heritable. Several regions across the genome have been implicated in containing genes that confer liability to nicotine dependence and variation in individual genes has been associated with nicotine dependence. Smoking cessation measures are also heritable, and measured genetic variation is associated with nicotine dependence treatment efficacy. Despite significant strides in the understanding of the relative contribution of genetic and environmental factors to nicotine dependence and treatment, emergent challenges necessitate interdisciplinary coordinated effort for effective problem solving. These challenges include refinement of the nicotine dependence phenotype, better understanding of the dynamic interplay between genes and environment in nicotine dependence etiology, application and development of molecular and statistical methodology that can adequately address vast amounts of data, and continuous translational cross-talk.     

Exposure to chronic intermittent nicotine vapor induces nicotine dependence

Animal models of drug exposure are important tools for the study of the neurobiological mechanisms of nicotine dependence and as preclinical models for medication development. There are few non-invasive animal models of nicotine exposure and currently there is no known animal model of second-hand exposure to nicotine. We hypothesized that chronic administration of nicotine vapors would produce blood levels of nicotine in rodents that are clinically relevant to those observed in human smoking and that rodents exposed to nicotine vapors would develop dependence to nicotine. We developed a system that vaporizes nicotine in the air in a stable, reliable and consistent manner. Intermittent exposure to nicotine vapor (0.2 mg/m³) for 8 or 14 h per day for 7 days produced a concentration of nicotine in the blood of 22 ng/mL. Sixteen hours after removal from nicotine vapors, rats showed significant somatic withdrawal signs precipitated by mecamylamine (1.5 mg/kg). These results provide a new rodent model of nicotine dependence using vapor administration that produces consistent levels of nicotine in the blood that are relevant for both heavy smoking and second-hand smoking, using a non-invasive technique that mimics the intermittent aspect and route of administration in humans.     

Clinical features of nicotine dependence]

Nicotine dependence is characterized by weak dependence potential and less ability to produce psychotoxicity and social disturbance. A two-compartment model consisting of "dependence" and "dependence syndrome" was used to clarify clinical features of nicotine dependence. "Dependence" was defined by drug liking. "Dependence syndrome" was defined by a compulsion to take a drug, and drug-induced pathological symptoms (withdrawal syndrome and acute disorders) and social disturbance. Nicotine produced a mild or the least degree of drug liking and withdrawal syndrome, without any significant social disturbance, or acute disorders. Thus, nicotine dependence differed from other forms of drug dependence in that nicotine was not associated with "dependence syndrome". This review also introduced other current topics of nicotine dependence. First, adolescence is regarded as a risk factor for the development of nicotine dependence, whereas the involvement of gender difference (female) in this respect is controversial. Secondly, many smokers feel difficulties in quitting smoking in spite of the weak dependence potential of nicotine, which is known as the "nicotine paradox". Several working hypotheses have been presented to explain this phenomenon. For example, nicotine has relatively strong conditioning effects and/or dependence liability compared with other drugs of abuse. However, further studies should be carried out to clarify clinical characteristics of the "nicotine paradox".     

Prolonged nicotine dependence associated with extended access to nicotine self-administration in rats

Rationale Most nicotine self-administration (NSA) studies in rats are performed under limited-access conditions. Few studies have examined the relationship between nicotine dependence and NSA.Objectives To determine how NSA access conditions affect NSA and the duration of nicotine dependence during abstinence, as reflected in somatic signs of withdrawal precipitated by administration of the nicotinic receptor antagonist mecamylamine.Methods The effects of different NSA access conditions (zero, 1 h/5 days, 1 h/7 days and 6 h/7 days per week) and non-contingent nicotine administration on NSA and somatic signs were examined.Results Daily NSA access (30 days) resulted in spontaneous and mecamylamine-induced somatic signs. Both daily access groups (1 h/day and 6 h/day, 7 days/week) exhibited spontaneous somatic signs on day 25 of NSA (17 h post-NSA) and sensitivity to mecamylamine up to 2 and 4 weeks of abstinence, respectively. In contrast, the 1 h/day, 5 days/week access group exhibited mecamylamine-induced somatic signs only up to 1 week of abstinence. NSA behavior was stable in rats with 1 h/day 5 days/week and 1 h/day 7 days/week access, but decreased from initially high rates in the 6 h/day 7 days/week access group, and decreased in rats receiving non-contingent nicotine. In contrast, extended cocaine self-administration access resulted in a gradual escalation in cocaine intake.Conclusion There was no escalation in nicotine intake with extended access conditions, unlike cocaine self-administration. Nevertheless, daily nicotine self-administration seven days per week, for either 1 or 6 h per day, was sufficient to induce long-lasting adaptations in nicotinic acetylcholine receptor activity reflected in spontaneous and antagonist-precipitated somatic signs of withdrawal, possibly reflecting aspects of nicotine dependence.     

Limitations in the assessment of DSM-IV cannabis tolerance as an indicator of dependence in adolescents

The usefulness of the Diagnostic and Statistical Manual's (4th ed.; DSM-IV; American Psychiatric Association, 1994) tolerance criterion as an indicator of dependence has been debated. The authors of this study evaluated the performance of DSM's cannabis tolerance criterion, operationally defined as a percentage increase in quantity needed to get high, in distinguishing adolescents with and without cannabis dependence. Two samples of adolescent cannabis users (ages 12-19) provided data (ns = 417 and 380). Tolerance, defined as a percentage increase (median increase = 300% and 175%, respectively, in the samples), had only moderate overall sensitivity and specificity in distinguishing those with and without cannabis dependence. Results suggest limitations of the DSM-IV and change-based operational definition of tolerance in adolescents.     

On the development of nicotine dependence in adolescence

Little is known about the natural history of drug dependence. This article describes the development and predictors of DSM-IV nicotine dependence in adolescence when tobacco use is initiated. In a two-stage design, a survey was administered to 6th-10th graders in the Chicago Public Schools to select a cohort of adolescents. Household interviews were conducted with adolescents five times and with one parent (predominantly mothers) three times over 2 years. The analytical sample includes 353 youths, who started using tobacco within 12 months preceding Wave 1 or between Waves 1-5. Survival analysis estimated latency to individual DSM-IV nicotine dependence criteria and the full dependence syndrome. Twenty-five percent of youths experienced the syndrome within 23 months of tobacco use onset. Tolerance, impaired control and withdrawal were experienced most frequently. Youths who developed full dependence experienced their first symptom faster after tobacco use onset than those who experienced only one criterion through the end of the observation period. Cox proportional hazards models estimated the importance of time-constant and time-varying sociodemographic, tobacco and other drug use, parental and peer smoking, social psychological and biological risk factors for experiencing the first criterion and the full syndrome. Pleasant initial sensitivity to tobacco and number of cigarettes smoked the prior month predicted both outcomes. Parental dependence predicted the full syndrome. Significant covariates were generally the same across gender and racial/ethnic subgroups. The predictive significance of the initial smoking experience and parental dependence highlight the potential importance of genetic factors in the etiology of nicotine dependence.     

尼古丁依赖与酒依赖共病机制的研究进展

尼古丁依赖和酒依赖是导致发病及死亡的两大主要因素[1],并且有较高的共患率[2].虽然尼古丁和酒精较少有相似的药理学特性.例如,尼古丁有专门的受体并且可以提高警觉、促进肌肉收缩;而酒精可以作用于多种类型的受体、降低警戒以及使肌肉松弛.但是,尼古丁和酒精都可以产生耐受和依赖,有很多研究显示一种成瘾性物质的使用会增加其他成瘾性物质的使用风险;更有许多研究显示,吸烟和饮酒之间存在一些关联.本文主要阐述酒依赖和尼古丁依赖共病的可能机制.     

Difference between alcohol dependence and nicotine dependence in cognitive dysfunction]

The extent of cognitive dysfunction in the nicotine and/or alcohol dependent subjects has been evaluated with Digit Span, Number Connection Test and Wisconsin Card-Sorting Test. Samples were divided into 4 groups, 8 subjects with alcohol and nicotine dependence, 9 subjects with alcohol dependence, 10 subjects with nicotine dependence and 31 subjects without the dependences who met ICD-10 criteria for dependence syndrome. The performance times of Number Connection Test were prolonged in the alcohol dependence and the presence of the nicotine dependence did not influence the performance times of Number Connection Test. The performances on the Wisconsin Card-Sorting Test were impaired by the alcohol dependence and the presence of the nicotine dependence did not influence the performances on the Wisconsin Card-Sorting Test.     

Current pharmacological treatments for nicotine dependence

There are nearly 1.1 billion users of nicotine and tobacco products worldwide. Tobacco use through cigarette smoking is the leading preventable cause of death in the world and kills nearly four million people annually. However, although some cigarette smokers are able to quit, many are not, and standard medications to assist in smoking cessation (e.g. nicotine-replacement therapies and sustained-release bupropion) are ineffective in many remaining smokers. Recent developments in our understanding of the neurobiology of nicotine dependence have identified several neurotransmitter systems that might contribute to the process of smoking maintenance and relapse, including dopamine, noradrenaline, 5-hydroxytryptamine, acetylcholine, endogenous opioids, GABA, glutamate and endocannabinoids. Several existing medications are being tested as treatments for nicotine dependence and novel investigational agents are under development as effective treatments for nicotine dependence in the 'hard to treat' tobacco user.     

Prevalence of DSM/ICD-defined nicotine dependence

This review compares nicotine dependence and the ability to stop smoking in smokers with no alcohol problems to smokers with current, past or lifetime (i.e., either current or past) alcohol problems. We searched computerized databases, meeting abstracts and made requests to listserves and grantees for comparisons of the above categories. We could not use meta-analyses and, thus, used consistency across studies to make conclusions. We located 17 articles on nicotine dependence, 12 on the ability to quit on a given attempt, 7 on lifetime quitting and 2 on quit attempts. Smokers with current and past alcohol problems were more nicotine dependent than smokers with no alcohol problems. Surprisingly, smokers with past problems were as able to quit on a given attempt as smokers with no problems. We hypothesize this may be because such smokers learned skills in resolving their alcohol problems that neutralized their increased nicotine dependence. Smokers with current or past alcohol problems appear to be less likely to quit in their lifetime. Given their equal ability to quit on a given attempt, this could be due to fewer quit attempts; however, whether this is actually so is unclear. Our results that smokers with past alcohol problems can quit as easily as those without alcohol problems suggest that smokers with past alcohol problems may respond to minimal treatments for smoking cessation.     

Tobacco smoke exposure induces nicotine dependence in rats

Rationale

Tobacco smoke contains nicotine and many other compounds that act in concert on the brain reward system. Therefore, animal models are needed that allow the investigation of chronic exposure to the full spectrum of tobacco smoke constituents.

Objectives

The aim of these studies was to investigate if exposure to tobacco smoke leads to nicotine dependence in rats.

Methods

The intracranial self-stimulation procedure was used to assess the negative affective aspects of nicotine withdrawal. Somatic signs were recorded from a checklist of nicotine abstinence signs. Nicotine self-administration sessions were conducted to investigate if tobacco smoke exposure affects the motivation to self-administer nicotine. Nicotinic receptor autoradiography was used to investigate if exposure to tobacco smoke affects central α7 nicotinic acetylcholine receptor (nAChR) and non-α7 nAChR levels (primarily α4β2 nAChRs).

Results

The nAChR antagonist mecamylamine dose-dependently elevated the brain reward thresholds of the rats exposed to tobacco smoke and did not affect the brain reward thresholds of the untreated control rats. Furthermore, mecamylamine induced more somatic withdrawal signs in the smoke-exposed rats than in the control rats. Nicotine self-administration was decreased 1 day after the last tobacco smoke exposure sessions and was returned to control levels 5 days later. Tobacco smoke exposure increased the α7 nAChR density in the CA2/3 area and the stratum oriens and increased the non-α7 nAChR density in the dentate gyrus.

Conclusion

Tobacco smoke exposure leads to nicotine dependence as indicated by precipitated affective and somatic withdrawal signs and induces an upregulation of nAChRs in the hippocampus.     

The retest reliability of nicotine dependence measures

Four variables potentially indicative of different aspects of drug problems have been selected for study in a community sample of young people aged 16–20 who use drugs; Severity of Dependence Score; Whether or not interactional problems caused by own drug use were experienced; Number of college or work days missed specifically as a result of drug use; and 12-item General Health Questionnaire Score. The study population comprised 200 young cannabis users, approximately one-third of whom were also stimulant drug users. Substantial levels of these problems were observed.

A range of predictors of these problems were identified in regression models. Lifetime stimulant drug use emerges as a principal indicator of risk. In addition, age, ongoing drug consumption variables and satisfaction with personal drug use emerge are recurrent predictors. An indicator of deprivation is identified as being associated with interactional problems. The need for development of the study of drug problems in the context of the normalisation of recreational drug use within British youth culture is discussed. More elaborate and sophisticated studies of problems will be required to identify significant harms as consequences of teenage patterns of non-opiate drug use.