Nicotine receptor partial agonists for smoking cessation

Mifepristone decreases nicotine intake in dependent and non-dependent adult rats

BACKGROUND

Addiction to tobacco and nicotine products has adverse health effects and afflicts more than a billion people worldwide. Therefore, there is an urgent need for new treatments to reduce tobacco and nicotine use. Glucocorticoid receptor blockade shows promise as a novel treatment for drug abuse and stress-related disorders.

AIM

These studies aim to investigate whether glucocorticoid receptor blockade with mifepristone diminishes the reinforcing properties of nicotine in rats with intermittent or daily long access to nicotine.

METHODS

The rats self-administered 0.06 mg/kg/inf of nicotine for 6 h per day, with either intermittent or daily access for 4 weeks before treatment with mifepristone. Daily nicotine self-administration models regular smoking, while intermittent nicotine self-administration models occasional smoking. To determine whether the rats were dependent, they were treated with the nicotinic acetylcholine receptor antagonist mecamylamine, and somatic signs were recorded.

RESULTS

The rats with intermittent access to nicotine had a higher level of nicotine intake per session than those with daily access but only the rats with daily access to nicotine showed signs of physical dependence. Furthermore, mecamylamine increased nicotine intake during the first hour of access in rats with daily access but not in those with intermittent access. Mifepristone decreased total nicotine intake in rats with intermittent and daily access to nicotine. Moreover, mifepristone decreased the distance traveled and rearing in the open field test and operant responding for food pellets.

CONCLUSION

These findings indicate that mifepristone decreases nicotine intake but this effect may be partially attributed to the sedative effects of mifepristone.

Nicotine vaping products as a harm reduction tool among smokers: Review of evidence and implications for pharmacy practice

With the growing popularity and use of nicotine vaping products (NVPs, also known as e-cigarettes) as a way to quit smoking, pharmacy staff are frequently asked by smokers for advice about NVPs. In Australia, there are currently no clear guidelines or policy statements provided by any of the professional organisations for pharmacists on how they should handle customer enquiries about NVPs, or on extemporaneous compounding of prescriptions for nicotine solution for use in NVPs as a smoking cessation aid. This commentary summarises the current evidence surrounding the safety and efficacy of NVPs, the Australian regulatory landscape, and provides a guide for pharmacy staff to use in discussions with customers regarding NVPs. Evidence strongly points to NVPs being considerably less harmful than smoking tobacco cigarettes and that they can be effective for smoking cessation. The maximum benefit from using NVPs as a harm reduction tool, however, will only be realised if smokers completely stop smoking rather than using NVPs as a partial substitute, because even low level smoking still confers substantial health risk. Vaping products containing nicotine are illegal to sell in Australia but users can still legally access nicotine e-liquid through some limited pathways if they hold a valid prescription from a registered medical practitioner. It is important that pharmacy staff keep abreast of the current evidence surrounding these products and provide evidence-based advice to customers.

Increased interregional functional connectivity of anterior insula is associated with improved smoking cessation outcome

Damage to the insular cortex has been shown to disrupt smoking behavior. However, whether smoking cessation outcomes are associated with abnormal functions of insula and its subregions remains unclear. In this study, we investigated the relationship between insular functions (interregional functional connectivity and regional activity) and treatment outcomes of cigarette smoking. Thirty treatment-seeking smokers were recruited into the treatment study and underwent magnetic resonance imaging (MRI) scans immediately before and after the treatment. Sixteen participants remained abstinent from smoking (quitters), while 14 relapsed to smoking (relapers). Changes in resting-state functional connectivity and fractional amplitude of low frequency fluctuation (fALFF) across groups and visits were assessed using repeated measures ANCOVA. Significant interaction effects were detected: 1) between the left anterior insula and left precuneus; and 2) between the right anterior insula and left precuneus and medial frontal gyrus. Post-hoc region-of-interest analyses in brain areas showing interaction effects indicated significantly increased functional connectivity after treatment compared with before treatment in quitters but opposite longitudinal changes in relapsers. However, no significant effects in fALFF were observed. These novel findings suggest that increased interregional functional connectivity of the anterior insula is associated with improved smoking cessation outcome: individuals with increased functional connectivity of the anterior insula during the treatment would more likely quit smoking successfully. These insular circuits may serve as therapeutic targets for more efficacious treatment of nicotine addiction.

[The prevalence of strategies for cessation of tobacco use in primary health care: an integrative review]

The habit of tobacco use/smoking, which is a major concern of Primary Health Care (PHC), is a serious public health problem and the main avoidable cause of death in the world. The relevance of actions, whose focus is to facilitate the cessation of this habit, motivates the discussion of studies that have different approaches to tackle this issue by seeking to train PHC professionals accordingly. A search was conducted in the Lilacs, MEDLINE and Web of Science databases for recent scientific publications (2010-2015). The key words were combined with Boolean operators and, after analysis of the articles found, 75 are discussed in this article since they have strategies with a higher prevalence in PHC. The conclusion drawn is that the brief or intense individual approach using the 5A method (Transtheoretical Model) is the most widely adopted, as well as bupropion and nicotine replacement patches. The increasing use of hard technology requires new studies that examine their impact on the treatment of smokers. It was clearly revealed that there is a need for health professionals to be better prepared to address the issue with the users, in addition to a lack of stimulus and proper conditions to work in the PHC team directly reflecting scientific advances in clinical practice.

Exploring the interoceptive stimulus effects of nicotine and varenicline

Learning processes associated with nicotine influence the development of addiction to tobacco products. In the present report, we are interested in the interoceptive stimulus effects of nicotine acquiring control over appetitive behaviors - specifically, reward seeking. Also of interest is the current smoking cessation drug, varenicline (Chantix®). Varenicline, with its nicotine-like stimulus effects, can decrease withdrawal and cravings for a subset of individuals addicted to nicotine, though relapse is still common. We trained rats (N = 48) with nicotine (0.4 mg/kg, SC) as an excitatory stimulus (i.e., paired with sucrose) in a drug-discriminated goal-tracking (DGT) task. There was no access to sucrose on interspersed saline days. After acquisition of the initial nicotine-saline discrimination, rats were separated into four groups to test discrimination reversal and drug substitution. The control group maintained nicotine as the excitatory stimulus (NIC+). The substitution group had varenicline (1 mg/kg) replace nicotine as the stimulus paired with sucrose (VAR+). One reversal group had nicotine signal the absence of sucrose (i.e., now available on intermixed saline sessions; NIC-). The last group was similar to the NIC- group except varenicline replaced nicotine on non-reinforced sessions (VAR-). We found that varenicline fully substituted as the training stimulus when the drug-sucrose relation remained in place (VAR+). Both reversal groups acquired the new discrimination, albeit slowly and more variable for the VAR- group in comparison to NIC-. There was an effect of group during substitution testing. Specifically, nicotine fully substituted for varenicline regardless of condition. However, varenicline only partially substituted for the nicotine stimulus. At the start of extinction, responding mimicked that of the rats training condition. However, by extinction session 12, all groups maintained similarly low levels of responding. These findings show nicotine and varenicline share stimulus elements, yet the conclusion of partial to full substitution depends on the nature of the testing protocol.

Smoking cessation intervention delivered by social service organisations for a diverse population of Australian disadvantaged smokers: A pragmatic randomised controlled trial

OBJECTIVES

There remains a need to identify effective smoking cessation interventions in severely disadvantaged populations. This trial aimed to examine the effectiveness of an intervention (Call it Quits) developed to promote smoking cessation and delivered by community social service case-workers.

METHODS

Call it Quits was a pragmatic, parallel randomised trial of a case-worker delivered smoking cessation intervention conducted in a non-government community social service organisation in New South Wales (NSW), Australia. Adult smokers requiring financial assistance were randomly assigned to the five-session Call it Quits intervention or usual care control group. Of the 618 eligible individuals, 300 were randomised to the intervention group, of whom 187 (62%) consented and 318 were randomised to the control group, of whom 244 (77%) consented, resulting in 431 participants. The primary outcome measure was self-reported continuous abstinence up to 6-month follow-up with biochemical verification. Primary analysis was performed using all the available data from participants under the assumption the data is missing completely at random, followed by sensitivity analyses.

RESULTS

No statistically significant differences in the primary outcome were found (1.4% in the control group versus 1.0% in the intervention group, OR = 0.77, p = 0.828).

CONCLUSIONS

A multi-component smoking cessation intervention delivering motivational interviewing-based counselling and free NRT by a trained case-worker within a community social service setting was not effective at achieving abstinence in a highly disadvantaged sample of smokers but increased attempts to stop and led to a reduction in number of cigarettes smoked daily.

Increased network centrality as markers of relapse risk in nicotine-dependent individuals treated with varenicline

Identifying smokers at high risk of relapse could improve the effectiveness of cessation therapies. Although altered regional brain function in smokers has been reported, whether the whole-brain functional organization differs smokers with relapse vulnerability from others remains unclear. Thus, the goal of this study is to investigate the baseline functional connectivity differences between relapsers and quitters. Using resting-state fMRI, we acquired images from 57 smokers prior to quitting attempts. After 12-week treatment with varenicline, smokers were divided into relapsers (n=36) and quitters (n=21) (quitter: continuously abstinent for weeks 9-12). The smoking cessation outcomes were cross-validated by self-reports and expired carbon monoxide. We then used eigenvector centrality (EC) mapping to identify the functional connectivity differences between relapsers and quitters. When compared to quitters, increased EC in the right dorsolateral prefrontal cortex (DLPFC), left middle temporal gyrus (MTG) and cerebellum anterior lobe was observed in relapsers. In addition, a logistic regression analysis of EC data (with DLPFC, MTG and cerebellum included) predicted relapse with 80.7% accuracy. These findings suggest that the DLPFC, MTG and cerebellum may be important substrates of smoking relapse vulnerability. The data also suggest that relapse-vulnerable smokers can be identified before quit attempts, which could enable personalized treatment and improve smoking cessation outcomes.

[Psychotherapy and pharmacotherapy for harmful tobacco use and tobacco dependency]

Tobacco consumption is one of the major preventable health risk factors. In Germany approximately 110,000 people prematurely die from tobacco-related diseases and approximately 50% of regular smokers are considered to be tobacco dependent. Nevertheless, motivation to quit smoking is low and the long-term abstinence rates after attempts to stop smoking without professional support are far below 10%. As part of the S3 treatment guidelines 78 recommendations for motivation and early interventions for smokers unwilling to quit as well as psychotherapeutic and pharmacological support for smokers willing to quit were formulated after an systematic search of the current literature. More than 50 professional associations adopted the recommendations and background information in a complex certification process. In this article the scientific evidence base regarding the psychotherapeutic and pharmacological treatment options as well as recommendations and further information about indications and treatment implementation are presented. By following these guidelines for treatment of heavy smokers who are willing to quit combined with individual and group therapies on the basis of behavioral treatment strategies and pharmacological support, long-term success rates of almost 30% can be achieved.

A rare missense mutation in CHRNA4 associates with smoking behavior and its consequences

Using Icelandic whole-genome sequence data and an imputation approach we searched for rare sequence variants in CHRNA4 and tested them for association with nicotine dependence. We show that carriers of a rare missense variant (allele frequency=0.24%) within CHRNA4, encoding an R336C substitution, have greater risk of nicotine addiction than non-carriers as assessed by the Fagerstrom Test for Nicotine Dependence (P=1.2 × 10(-4)). The variant also confers risk of several serious smoking-related diseases previously shown to be associated with the D398N substitution in CHRNA5. We observed odds ratios (ORs) of 1.7-2.3 for lung cancer (LC; P=4.0 × 10(-4)), chronic obstructive pulmonary disease (COPD; P=9.3 × 10(-4)), peripheral artery disease (PAD; P=0.090) and abdominal aortic aneurysms (AAAs; P=0.12), and the variant associates strongly with the early-onset forms of LC (OR=4.49, P=2.2 × 10(-4)), COPD (OR=3.22, P=2.9 × 10(-4)), PAD (OR=3.47, P=9.2 × 10(-3)) and AAA (OR=6.44, P=6.3 × 10(-3)). Joint analysis of the four smoking-related diseases reveals significant association (P=6.8 × 10(-5)), particularly for early-onset cases (P=2.1 × 10(-7)). Our results are in agreement with functional studies showing that the human α4β2 isoform of the channel containing R336C has less sensitivity for its agonists than the wild-type form following nicotine incubation.

Relative potency of varenicline or fluvoxamine to reduce responding for ethanol versus food depends on the presence or absence of concurrently earned food

BACKGROUND

Varenicline, a nicotinic partial agonist, selectively reduces ethanol (EtOH)- versus sucrose-maintained behavior when tested in separate groups, yet like the indirect agonist fluvoxamine, this selectively inverts when EtOH and food are concurrently available.

METHODS

Here, we extend these findings by examining varenicline and fluvoxamine effects under a multiple concurrent schedule where food and EtOH are concurrently available in different components: Component 1 where the food fixed-ratio was 25 and Component 2 where the food fixed-ratio was 75. The EtOH fixed-ratio was always 5. Food-maintained responding predominated in Component 1, while EtOH-maintained responding predominated in Component 2. In a second experiment, varenicline effects were assessed under a multiple schedule where food, then EtOH, then again food were available in separate 5-minute components with fixed-ratios of 5 for each reinforcement.

RESULTS

In the multiple concurrent schedule, varenicline was more potent at reducing food- versus EtOH-maintained responding in both components and reduced EtOH-maintained responding more potently during Component 1 (when food was almost never earned) than in Component 2 (where food was often earned). Fluvoxamine was similarly potent at reducing food- and EtOH-maintained responding. Under the multiple schedule, varenicline, like fluvoxamine, more potently decreases EtOH- versus food maintained responding when only food or EtOH is available in separate components.

CONCLUSIONS

These results demonstrate that selective effects on drug- versus alternative-maintained behavior depend on the schedule arrangement, and assays in which EtOH or an alternative is the only programmed reinforcement may overestimate the selectivity of treatments to decrease EtOH self-administration. Thus selective effects obtained under one assay may not generalize to another. Better understanding the behavioral mechanisms responsible for these results may help to guide pharmaco-therapeutic development for substance use disorders.

Randomized trial of nicotine replacement therapy (NRT), bupropion and NRT plus bupropion for smoking cessation: effectiveness in clinical practice

BACKGROUND AND AIMS

Bupropion was introduced for smoking cessation following a pivotal trial showing that it gave improved efficacy over the nicotine patch and also suggesting combination treatment was beneficial. We tested in clinical practice for an effectiveness difference between bupropion and nicotine replacement therapy (NRT), whether the combination improves effectiveness and whether either treatment might be more beneficial for certain subgroups of smokers.

DESIGN

Open-label randomized controlled trial with 6-month follow-up.

SETTING

Four UK National Health Service (NHS) smoking cessation clinics.

PARTICIPANTS

Smokers (n = 1071) received seven weekly behavioural support sessions and were randomized to an NRT product of their choice (n = 418), bupropion (n = 409) or NRT plus bupropion (n = 244).

MEASURES

The primary outcome was self-reported cessation over 6 months, with biochemical verification at 1 and 6 months. Also measured were baseline demographics, health history, smoking characteristics and unwanted events during treatment.

FINDINGS

Abstinence rates for bupropion (27.9%) and NRT (24.2%) were not significantly different (odds ratio = 1.21, 95% confidence interval = 0.883-1.67), and the combination rate (24.2%) was similar to that for either treatment alone. There was some evidence that the relative effectiveness of bupropion and NRT differed according to depression (χ(2) = 2.86, P = 0.091), with bupropion appearing more beneficial than NRT in those with a history of depression (29.8 versus 18.5%). Several unwanted symptoms were more common with bupropion.

CONCLUSION

There is no difference in smoking cessation effectiveness among bupropion, nicotine replacement therapy and their combination when used with behavioural support in clinical practice. There is some evidence that bupropion is more beneficial than nicotine replacement therapy for smokers with a history of depression.

Common and distinct neural targets of treatment: changing brain function in substance addiction

Neuroimaging offers an opportunity to examine the neurobiological effects of therapeutic interventions for human drug addiction. Using activation likelihood estimation, the aim of the current meta-analysis was to quantitatively summarize functional neuroimaging studies of pharmacological and cognitive-based interventions for drug addiction, with an emphasis on their common and distinct neural targets. More exploratory analyses also contrasted subgroups of studies based on specific study and sample characteristics. The ventral striatum, a region implicated in reward, motivation, and craving, and the inferior frontal gyrus and orbitofrontal cortex, regions involved in inhibitory control and goal-directed behavior, were identified as common targets of pharmacological and cognitive-based interventions; these regions were observed when the analysis was limited to only studies that used established or efficacious interventions, and across imaging paradigms and types of addictions. Consistent with theoretical models, cognitive-based interventions were additionally more likely to activate the anterior cingulate cortex, middle frontal gyrus, and precuneus, implicated in self-referential processing, cognitive control, and attention. These results suggest that therapeutic interventions for addiction may target the brain structures that are altered across addictions and identify potential neurobiological mechanisms by which the tandem use of pharmacological and cognitive-based interventions may yield synergistic or complementary effects. These findings could inform the selection of novel functional targets in future treatment development for this difficult-to-treat disorder.

The Gold Standard Programme: smoking cessation interventions for disadvantaged smokers are effective in a real-life setting

OBJECTIVES

To evaluate the real-life effect of an evidence-based Gold Standard Programme (GSP) for smoking cessation interventions in disadvantaged patients and to identify modifiable factors that consistently produce the highest abstinence rates.

DESIGN

Observational prospective cohort study.

SETTING

GSPs in pharmacies, hospitals and communities in Denmark, reporting to the national Smoking Cessation Database.

PARTICIPANTS

Disadvantaged patients, defined as patients with a lower level of education and those receiving unemployment benefits.

INTERVENTIONS

6-week manualised GSP smoking cessation interventions performed by certified staff.

MAIN OUTCOME MEASURES

6 months of continuous abstinence, response rate: 80%.

RESULTS

Continuous abstinence of the 16 377 responders was 34% (of all 20 588 smokers: 27%). Continuous abstinence was lower in 5738 smokers with a lower educational level (30% of responders and 23% of all) and in 840 unemployed (27% of responders and 19% of all). In respect to modifiable factors, continuous abstinence was found more often after programmes in one-on-one formats (vs group formats) among patients with a lower educational level, 34% (vs 25%, p=0.037), or among unemployed, 35% (vs 24%, p=0.099). The variable 'format' stayed in the final model of multivariable analyses in patients with a lower educational level, OR=1.31 (95% CI 1.05 to 1.63).

CONCLUSIONS

Although continuous abstinence was lower among disadvantaged smokers, the absolute difference was small. If the programme had been as effective in disadvantaged as in non-disadvantaged groups, there would have been an extra 46 or 8 quitters annually, respectively. Promoting individual interventions among those with a low education may increase the effectiveness of GSP.

How pragmatic or explanatory is the randomized, controlled trial? The application and enhancement of the PRECIS tool to the evaluation of a smoking cessation trial

BACKGROUND

Numerous explanatory randomized trials support the efficacy of chronic disease interventions, including smoking cessation treatments. However, there is often inadequate adoption of these interventions for various reasons, one being the limitation of generalizability of the explanatory studies in real-world settings. Randomized controlled trials can be rated as more explanatory versus pragmatic along 10 dimensions. Pragmatic randomized clinical trials generate more realistic estimates of effectiveness with greater relevance to clinical practice and for health resource allocation decisions. However, there is no clear method to scale each dimension during the trial design phase to ensure that the design matches the intended purpose of the study.

METHODS

We designed a pragmatic, randomized, controlled study to maximize external validity by addressing several barriers to smoking cessation therapy in ambulatory care. We analyzed our design and methods using the recently published 'Pragmatic-Explanatory Continuum Indicatory Summary (PRECIS)' tool, a qualitative method to assess trial design across 10 domains. We added a 20-point numerical rating scale and a modified Delphi process to improve consensus in rating these domains.

RESULTS

After two rounds of review, there was consensus on all 10 domains of study design. No single domain was scored as either fully pragmatic or fully explanatory; but overall, the study scored high on pragmatism.

CONCLUSIONS

This addition to the PRECIS tool may assist other trial designers working with interdisciplinary co-investigators to rate their study design while building consensus.

Tobacco addiction and the dysregulation of brain stress systems

Tobacco is a highly addictive drug and is one of the most widely abused drugs in the world. The first part of this review explores the role of stressors and stress-associated psychiatric disorders in the initiation of smoking, the maintenance of smoking, and relapse after a period of abstinence. The reviewed studies indicate that stressors facilitate the initiation of smoking, decrease the motivation to quit, and increase the risk for relapse. Furthermore, people with depression or an anxiety disorder are more likely to smoke than people without these disorders. The second part of this review describes animal studies that investigated the role of brain stress systems in nicotine addiction. These studies indicate that corticotropin-releasing factor, Neuropeptide Y, the hypocretins, and norepinephrine play a pivotal role in nicotine addiction. In conclusion, the reviewed studies indicate that smoking briefly decreases subjective stress levels but also leads to a further dysregulation of brain stress systems. Drugs that decrease the activity of brain stress systems may diminish nicotine withdrawal and improve smoking cessation rates.

Varenicline as a smoking cessation aid in a Greek population: a subanalysis of an observational study

BACKGROUND

Greece has the highest proportion of smokers in the European Union with 42% of Greeks admitting that they smoke, based on a 2009 survey. This post-hoc analysis of a prospective, observational study evaluated the effectiveness and safety profile of the smoking cessation aid varenicline, as well as potential predictors of quit success in a Greek population.

METHODS

Participants were prescribed varenicline according to the recommendations of the European Summary of Product Characteristics (1 mg twice daily). The 7-day point prevalence of abstinence at Week 12 was determined based on verbal reporting using a nicotine use inventory. Abstinence was confirmed by carbon monoxide measurements of exhaled air at the last visit of the study. The safety profile of varenicline was also assessed.

RESULTS

At baseline, the Greek subsample (n = 196) had a mean age of 42.6 years, with 54.6% of them being men. Participants had a smoking history of 23.5 years and a Fagerström Test for Nicotine Dependence total score of 6.6. After 12 weeks of varenicline therapy, 70.4% (95% CI, 64.0-76.7) of all participants had quit smoking. This increased to 86.2% among participants who had taken the study medication for 80% of the planned number of treatment days. Age was a significant predictor of quit success. The most frequently observed treatment-emergent adverse event was nausea, occurring in 13.3% of participants.

CONCLUSIONS

In this 'real-world' observational study, 70.4% of Greek smokers successfully quit smoking after 12 weeks of varenicline therapy, providing support that varenicline is an effective smoking cessation medication. Further studies with longer follow-up are warranted.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT00669240.

Alcohol and substance use in liver transplant patients

In this article the epidemiology of substance use and substance disorders in the United States and their association with liver disease are reviewed. The relevance of tobacco use and issues of candidacy as it pertains to substance use are discussed. The use of alcohol while on the waitlist and short sobriety are also addressed. The merits of monitoring of patients are discussed, and the outcomes of these patients after liver transplantation are examined. The article concludes with a summary of recommendations for clinicians working with these patients and possible future directions for both clinical care and research.

Australian smokers increasingly use help to quit, but number of attempts remains stable: findings from the International Tobacco Control Study 2002-09

OBJECTIVE

To assess interest in quitting smoking and quitting activity, and the use of pharmacotherapy and behavioural cessation support, among Australian smokers between 2002 and 2009.

METHODS

Data were taken from 3303 daily smokers taking part in a minimum of two consecutive waves of the International Tobacco Control Four Country Survey. Using weighted data to control for sampling and attrition, we explored any effects due to age, sex, whether living in a metropolitan or regional area, and nicotine dependence.

RESULTS

Around 40% of smokers reported trying to quit and, of these, about 23% remained abstinent for at least one month when surveyed. Low socioeconomic smokers were less likely to be interested in quitting and less likely to make a quit attempt. Reported use of prescription medication to quit smoking rose sharply at the last wave with the addition of varenicline to the pharmaceutical benefits scheme. Among those who tried, use of help rose gradually from 37% in 2002 to almost 59% in 2009 (including 52% using pharmacotherapy and 15% using behavioural forms of support).

IMPLICATIONS

Use of help to quit is now the norm, especially among more dependent smokers. This may reflect a realization among smokers that quitting unassisted is more likely to fail than quitting with help, as well as the cumulative effect of promoting the use of help. Given the continuing high levels of failed quit attempts, services need to be able to expand to meet this increasing demand.

Neuroscience of behavioral and pharmacological treatments for addictions

Although substantial advances have been made in behavioral and pharmacological treatments for addictions, moving treatment development to the next stage may require novel ways of approaching addictions, particularly ways based on new findings regarding the neurobiological underpinnings of addictions that also assimilate and incorporate relevant information from earlier approaches. In this review, we first briefly review theoretical and biological models of addiction and then describe existing behavioral and pharmacologic therapies for the addictions within this framework. We then propose new directions for treatment development and targets that are informed by recent evidence regarding the heterogeneity of addictions and the neurobiological contributions to these disorders.

Electronic cigarettes and thirdhand tobacco smoke: two emerging health care challenges for the primary care provider

PRIMARY CARE PROVIDERS SHOULD BE AWARE OF TWO NEW DEVELOPMENTS IN NICOTINE ADDICTION AND SMOKING CESSATION: 1) the emergence of a novel nicotine delivery system known as the electronic (e-) cigarette; and 2) new reports of residual environmental nicotine and other biopersistent toxicants found in cigarette smoke, recently described as "thirdhand smoke". The purpose of this article is to provide a clinician-friendly introduction to these two emerging issues so that clinicians are well prepared to counsel smokers about newly recognized health concerns relevant to tobacco use. E-cigarettes are battery powered devices that convert nicotine into a vapor that can be inhaled. The World Health Organization has termed these devices electronic nicotine delivery systems (ENDS). The vapors from ENDS are complex mixtures of chemicals, not pure nicotine. It is unknown whether inhalation of the complex mixture of chemicals found in ENDS vapors is safe. There is no evidence that e-cigarettes are effective treatment for nicotine addiction. ENDS are not approved as smoking cessation devices. Primary care givers should anticipate being questioned by patients about the advisability of using e-cigarettes as a smoking cessation device. The term thirdhand smoke first appeared in the medical literature in 2009 when investigators introduced the term to describe residual tobacco smoke contamination that remains after the cigarette is extinguished. Thirdhand smoke is a hazardous exposure resulting from cigarette smoke residue that accumulates in cars, homes, and other indoor spaces. Tobacco-derived toxicants can react to form potent cancer causing compounds. Exposure to thirdhand smoke can occur through the skin, by breathing, and by ingestion long after smoke has cleared from a room. Counseling patients about the hazards of thirdhand smoke may provide additional motivation to quit smoking.