Neurobiology of tobacco smoking and other addictive disorders

Dyshomeostasis, obesity, addiction and chronic stress

When eating control is overridden by hedonic reward, a condition of obesity dyshomeostasis occurs. Appetitive hedonic reward is a natural response to an obesogenic environment containing endemic stress and easily accessible and palatable high-energy foods and beverages. Obesity dyshomeostasis is mediated by the prefrontal cortex, amygdala and hypothalamic-pituitary-adrenal axis. The ghrelin axis provides the perfect signalling system for feeding dyshomeostasis, affect control and hedonic reward. Dyshomeostasis plays a central role in obesity causation, the addictions and chronic conditions and in persons with diverse bodies. Prevention and treatment efforts that target sources of dyshomeostasis provide ways of reducing adiposity, ameliorating the health impacts of addiction and raising the quality of life in people suffering from chronic stress.

The detox strategy in smoking comprising nutraceutical formulas of non-hydrolyzed carnosine or carcinine used to protect human health

The increased oxidative stress in patients with smoking-associated disease, such as chronic obstructive pulmonary disease, is the result of an increased burden of inhaled oxidants as well as increased amounts of reactive oxygen species generated by various inflammatory, immune and epithelial cells of the airways. Nicotine sustains tobacco addiction, a major cause of disability and premature death. In addition to the neurochemical effects of nicotine, behavioural factors also affect the severity of nicotine withdrawal symptoms. For some people, the feel, smell and sight of a cigarette and the ritual of obtaining, handling, lighting and smoking a cigarette are all associated with the pleasurable effects of smoking. For individuals who are motivated to quit smoking, a combination of pharmacotherapy and behavioural therapy has been shown to be most effective in controlling the symptoms of nicotine withdrawal. In the previous studies, we proposed the viability and versatility of the imidazole-containing dipeptide-based compounds in the nutritional compositions as the telomere protection targeted therapeutic system for smokers in combination with in vitro cellular culture techniques being an investigative tool to study telomere attrition in cells induced by cigarette smoke (CS) and smoke constituents. Our working therapeutic concept is that imidazole-containing dipeptide-based compounds (non-hydrolyzed carnosine and carcinine) can modulate the telomerase activity in the normal cells and can provide the redox regulation of the cellular function under the terms of environmental and oxidative stress and in this way protect the length and the structure of telomeres from attrition. The detoxifying system of non-hydrolyzed carnosine or carcinine can be applied in the therapeutic nutrition formulations or installed in the cigarette filter. Patented specific oral formulations of non-hydrolyzed carnosine and carcinine provide a powerful manipulation tool for targeted therapeutic inhibition of cumulative oxidative stress and inflammation and protection from telomere attrition associated with smoking. It is demonstrated in this work that both non-hydrolyzed carnosine and carcinine are characterized by greater bioavailability than pure l-carnosine subjected to enzymatic hydrolysis with carnosinase, and perform the detoxification of the α,β-unsaturated carbonyl compounds present in tobacco smoke. We argue that while an array of factors has shaped the history of the 'safer' cigarette, it is the current understanding of the industry's past deceptions and continuing avoidance of the moral implications of the sale of products that cause the enormous suffering and death of millions that makes reconsideration of 'safer' cigarettes challenging. In contrast to this, the data presented in the article show that recommended oral forms of non-hydrolyzed carnosine and carcinine protect against CS-induced disease and inflammation, and synergistic agents with the actions of imidazole-containing dipeptide compounds in developed formulations may have therapeutic utility in inflammatory lung diseases where CS plays a role.

Pharmacotherapy of smoking cessation

Nicotine in tobacco smoke causes not only pathophysiological changes in the smoker's body, but also develops tolerance to its own action with repeated use. Repeated exposure to nicotine develops neuroadaptation of the receptors, resulting in tolerance to many of the effects of nicotine. Pharmacotherapies for smoking cessation should reduce withdrawal symptoms and block the reinforcing effects of nicotine without causing excessive adverse effects. All forms of nicotine replacement therapy (NRT) - gum, patches and inhaler - and bupropion are safe and effective for increasing smoking cessation rates in the short and long-term use. Combination NRT (more than one therapy) may be indicated in patients who have failed monotherapy.

Smoking and suicidality in subjects with bipolar disorder: results from the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC)

BACKGROUND

Smoking in patients with bipolar disorder is known to be related to suicidality. This link has not been investigated, however, in community-based samples. The aim of this study is to delineate the sociodemographic and clinical characteristics of bipolar smokers and examine the relationship between these characteristics and suicidal ideation or attempts in an epidemiologic database, the National Epidemiological Survey on Alcohol and Related Conditions (NESARC).

METHODS

Subjects (n = 1,643) with bipolar disorder I and II, defined by the DSM-IV criteria, who had a history of low moods lasting more than 2 weeks were included in our analysis. Current smokers, former smokers, and lifetime nonsmokers were compared in terms of demographic, clinical characteristics, and functional level. Suicidality, evaluated by a history of suicide ideation and attempts while in low mood were compared.

RESULTS

Current smokers with bipolar disorder showed a greater number of DSM-IV symptoms while in acute episodes, higher rate of alcohol, and drug use disorders, as well as poorer functional levels than nonsmokers. Previous smokers displayed intermediate characteristics between current smokers and nonsmokers. The logistic regression analysis revealed that current smoking status predicted the risk of having a history of attempted suicide (Odds ratio 1.35, 95% CI: 1.05-1.76) after adjusting for age, sex, race, bipolar subtype, lifetime axis II/anxiety/alcohol use/substance use disorder; however, lifetime smoking status did not.

CONCLUSIONS

The present study confirms that current cigarette smoking can predict attempted suicide in a community representative sample of people with bipolar disorder.

Smoking and suicidality in subjects with major depressive disorder: results from the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC)

BACKGROUND

Detailed characteristics of depressive smokers and its association with suicidality were still less investigated. The aim of this study was to delineate characteristics of smokers with major depressive disorder (MDD) and examine the relationship between these characteristics and suicidality using an epidemiologic database, the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC).

METHODS

A total of 5695 subjects with MDD, defined by the DSM-IV criteria, were included in our analysis. Current smokers, former smokers, and lifetime nonsmokers were compared in terms of demographic, clinical characteristics, and functional level. Suicidality, evaluated by history of suicide ideation and attempts while in a low mood was evaluated and compared among the groups.

RESULTS

Current smokers with MDD showed a greater number of DSM-IV symptoms while in acute episodes, a higher rate of alcohol and drug-use disorders, and poorer functional levels than nonsmokers. Previous smokers displayed intermediate characteristics between current smokers and nonsmokers. The logistic regression analysis revealed that both current and former smoking status predicted the risk of having a history of attempted suicide (current smokers: odds ratio 1.62, 95% C.I. 1.42-1.86; former smokers: odds ratio 1.37, 95% C.I. 1.13-1.66) after adjusting for demographic data, a history of subthreshold hypomania, and a lifetime axis II/anxiety/alcohol use/substance-use disorder.

LIMITATIONS

Retrospective, cross-sectional evaluation; suicidality assessed only in the most severe depressive episode.

CONCLUSIONS

The present study corroborates that smokers with MDD showed distinct clinical characteristics, and cigarette smoking can predict attempted suicide in a community representative sample of people with MDD.

The pharmacist "toolbox" for smoking cessation: a review of methods, medicines, and novel means to help patients along the path of smoking reduction to smoking cessation

Annually there are 500 000 preventable deaths in the United States caused by smoking; as health care professionals, pharmacists have a unique opportunity to advise, assess, and assist patients to quit smoking. This review article provides pharmacists with a "toolbox" containing an overview of pharmacologic and nonpharmacologic methods for smoking cessation. Currently approved over-the-counter (OTC) and prescription medications (nicotine replacement therapy, varenicline, and bupropion) are summarized, and nonpharmacologic therapies discussed include cognitive therapy and hypnosis. In addition to traditional therapies some potential approaches to smoking cessation are addressed, including nicotine immunizations and electronic cigarettes.

The neurocircuitry of illicit psychostimulant addiction: acute and chronic effects in humans

Illicit psychostimulant addiction remains a significant problem worldwide, despite decades of research into the neural underpinnings and various treatment approaches. The purpose of this review is to provide a succinct overview of the neurocircuitry involved in drug addiction, as well as the acute and chronic effects of cocaine and amphetamines within this circuitry in humans. Investigational pharmacological treatments for illicit psychostimulant addiction are also reviewed. Our current knowledge base clearly demonstrates that illicit psychostimulants produce lasting adaptive neural and behavioral changes that contribute to the progression and maintenance of addiction. However, attempts at generating pharmacological treatments for psychostimulant addiction have historically focused on intervening at the level of the acute effects of these drugs. The lack of approved pharmacological treatments for psychostimulant addiction highlights the need for new treatment strategies, especially those that prevent or ameliorate the adaptive neural, cognitive, and behavioral changes caused by chronic use of this class of illicit drugs.

The neurocircuitry of illicit psychostimulant addiction: acute and chronic effects in humans

Illicit psychostimulant addiction remains a significant problem worldwide, despite decades of research into the neural underpinnings and various treatment approaches. The purpose of this review is to provide a succinct overview of the neurocircuitry involved in drug addiction, as well as the acute and chronic effects of cocaine and amphetamines within this circuitry in humans. Investigational pharmacological treatments for illicit psychostimulant addiction are also reviewed. Our current knowledge base clearly demonstrates that illicit psychostimulants produce lasting adaptive neural and behavioral changes that contribute to the progression and maintenance of addiction. However, attempts at generating pharmacological treatments for psychostimulant addiction have historically focused on intervening at the level of the acute effects of these drugs. The lack of approved pharmacological treatments for psychostimulant addiction highlights the need for new treatment strategies, especially those that prevent or ameliorate the adaptive neural, cognitive, and behavioral changes caused by chronic use of this class of illicit drugs.

From bedside to bench and back again: a 30-year saga

My work (Mark S. Gold) began in the 70s looking for the mechanisms of drug reinforcement and withdrawal. Through observation and experience, drugs of abuse and the drive for food appeared to be quite related. As pioneered by Bart Hoebel, food can become an object of desire and act in most respects as a drug of abuse. The Gold lab is investigating working models for pathological attachment to eating and food addiction. New pharmacological treatments which interfere with food reinforcement may be the next step.

The co-occurrence of cigarette smoking and bipolar disorder: phenomenology and treatment considerations

OBJECTIVES

  Despite recent advances in understanding the causes and treatment of nicotine dependence among individuals with psychiatric disorders, smoking among individuals with bipolar disorder (BD) has received little attention. The goal of this review is to synthesize the literature on the epidemiology, consequences, and treatment of smoking and nicotine dependence among individuals with BD and to delineate a future research agenda.

METHODS

  We conducted a PubMed search of English-language articles using the search terms bipolar disorder, mania, tobacco, nicotine, and smoking, followed by a manual search of the literature cited in the identified articles. Articles were chosen by the authors on the basis of their relevance to the topic areas covered in this selective review.

RESULTS

  Adults with BD are two to three times more likely to have started smoking and, on the basis of epidemiological data, may be less likely to initiate and/or maintain smoking abstinence than individuals without psychiatric disorders. Smoking cessation is achievable for individuals with BD, but challenges such as chronic mood dysregulation, high prevalence of alcohol and drug use, more severe nicotine dependence, and limited social support can make quitting more difficult. Effective treatments for tobacco cessation are available, but no controlled trials in smokers with BD have been conducted.

CONCLUSIONS

  Cigarette smoking is a prevalent and devastating addiction among individuals with BD and should be addressed by mental health providers. Additional research on the mechanisms of, and optimal treatment for, smoking and nicotine dependence in this population is desperately needed.

Pharmacologic agents for smoking cessation: a clinical review

Tobacco use has been clearly demonstrated to have negative health consequences. Smoking cigarettes is the predominant method of tobacco use. The tar contained within cigarettes and other similar products is also harmful. Other tarless tobacco containing products do exist but carry no significantly decreased risk. While nicotine is considered to be principally responsible for tobacco addiction, other chemicals in the cigarette smoke including acetaldehyde may contribute to the addictive properties of tobacco products. The adverse health consequences of tobacco use have been well documented. Studies have shown that a combined behavioral and pharmacological approach is more effective in smoking cessation than either approach alone. Pharmacotherapy can achieve 50% reduction in smoking. With pharmacotherapy the estimated 6-month abstinence rate is about 20%, whereas it is about 10% without pharmacotherapy. The first-line of drugs for smoking cessation are varenicline, bupropion sustained release, and nicotine replacement drugs, which are approved for use in adults. Data are insufficient to recommend their use in adolescents. This article reviews the use of pharmacological agents used for smoking cessation. A brief overview of epidemiology, chemistry, and adverse health effects of smoking is provided.

Contribution of hypothalamic-pituitary-adrenal activity and environmental stress to vulnerability for smoking in adolescents

Although tobacco smoking, which has been linked to depression, is a major public health problem, little is known about the neurobiological factors that confer vulnerability to smoking in youngsters and the effects of adolescent smoking on the course of depression. This study examined whether hypothalamic-pituitary-adrenal (HPA) activity and stressful life experiences are related to smoking behavior in depressed and non-depressed adolescents, and whether smoking predicts a worsening course of depression. Smoking history and stressful experiences were assessed in 151 adolescents (48 with no personal or family history of psychiatric disorder, 48 with no psychiatric history, but at high risk for depression by virtue of parental depression, and 55 with current major depressive disorder). Evening salivary cortisol and nocturnal urinary-free cortisol were measured for three consecutive evenings. The participants were then followed at regular intervals for up to 5 years to assess smoking history, clinical course of depression and stressful experiences during the follow-up period. Increased evening/night-time cortisol levels were associated with both initiation and persistence of smoking during follow-up. Stressful life experiences further increased the risk for smoking in depressed as well as non-depressed youth. Smoking was also associated with a higher frequency of depressive episodes during follow-up. A model that included stressful experiences and cortisol levels reduced the contribution of smoking per se to depression. High evening/night-time cortisol level appears to be a vulnerability marker for smoking in adolescents, with stressful experiences further increasing the risk for smoking in vulnerable youth. High evening/night-time cortisol levels and stressful experiences accounted, at least partially, for the association between depressive illness and smoking behavior.

Tobacco and psychiatric dual disorders

Smoking is a leading cause of morbidity and premature mortality in the United States. The relationship between tobacco smoking and several forms of cancer, heart disease, stroke, chronic lung disease, and other medical diseases is well recognized and accepted. Recent epidemiological studies are now focusing on the link between tobacco use and psychiatric diseases. Experts now suggest that in the differential diagnosis of "smoker," depression, alcohol dependence, and schizophrenia are highest on the list. Studies are also focusing on the role of secondhand tobacco exposure, either in utero or during childhood, in the risk of dual disorders. Prenatal exposure may alter gene expression and change the risk for a variety of life-long psychiatric diseases, e.g., ADD/ADHD, antisocial personality disorders, substance use disorders, and major depression. Considerable time and effort have been devoted to studying the link between smoking and depression and also schizophrenia. We will focus on less well-studied areas in tobacco use and psychiatric dual disorders (including eating disorders), prenatal and early childhood secondhand smoke (SHS) exposure, and the relationship to the genesis of these dual disorders.

Long-term use of medications and destructive periodontal disease

BACKGROUND

Knowledge of typical medication use among patients with chronic periodontitis or destructive periodontal disease is limited. The aim of this study was to associate periodontitis severity with the use of different classes of medications.

METHODS

Patients (N=12,631) who had medical, dental, and pharmaceutical coverage with a health maintenance organization and whose severity of destructive periodontal disease was diagnosed by a dentist or specialist were included in the study. The rate of drug use over 7 years was related to the severity of destructive periodontal disease by means of Poisson regression models.

RESULTS

Individuals with moderate to advanced periodontitis had significantly lower fill rates for the respiratory agents (antihistamines: -23%, 95% confidence interval [CI]: -10% to -34%; decongestants: -24%, 95% CI: -13% to -34%; and cough/cold medications: -12%, 95% CI: -3% to -21%) and anti-infective agents (antibiotics: -12%, 95% confidence interval: -6% to -18%; urinary anti-infectives: -36%, 95% CI: -6% to -56%; and topical antibiotics: -18%, 95% CI: -5% to -29%).

CONCLUSIONS

More severe periodontitis was a marker for reduced medication use for allergies and infections. The associations between destructive periodontal disease, infections, allergies, and the hygiene hypothesis need further exploration.

Role of acetaldehyde in tobacco smoke addiction

This review evaluates the presumed contribution of acetaldehyde to tobacco smoke addiction. In rodents, acetaldehyde induces reinforcing effects, and acts in concert with nicotine. Harman and salsolinol, condensation products of acetaldehyde and biogenic amines, may be responsible for the observed reinforcing effect of acetaldehyde. Harman and salsolinol inhibit monoamine oxidase (MAO), and some MAO-inhibitors are known to increase nicotine self-administration and maintain behavioural sensitization to nicotine. Harman is formed in cigarette smoke, and blood harman levels appear to be 2-10 times higher compared to non-smokers. Since harman readily passes the blood-brain barrier and has sufficient MAO-inhibiting potency, it may contribute to the lower MAO-activity observed in the brain of smokers. In contrast, the minor amounts of salsolinol that can be formed in vivo most likely do not contribute to tobacco addiction. Thus, acetaldehyde may increase the addictive potential of tobacco products via the formation of acetaldehyde-biogenic amine adducts in cigarette smoke and/or in vivo, but further research is necessary to substantiate this hypothesis.

Influence of nicotine on positive affect in anhedonic smokers

RATIONALE

The possibility that individuals administer nicotine to self-regulate persistent negative affect has received interest as a possible explanation for the high prevalence of affectively vulnerable smokers. Relatively overlooked, however, is the possibility that smokers might also self-administer nicotine to elevate low positive affect.

OBJECTIVES

This study examined whether nicotine administration augmented anhedonic smokers' positive affective response to a positive mood induction.

MATERIALS AND METHODS

Fifty regular smokers (50% female) underwent two positive mood inductions during which they smoked either a nicotinized or denicotinized cigarette in counterbalanced order. Positive affect was assessed before and at two time points after smoking.

RESULTS

Random effects regression showed a significant anhedonia by condition-by-time interaction [t(181)=-2.01, p = 0.04], supporting the hypothesis that anhedonia moderated nicotine's effect on changes in positive affect. Simple effect analyses showed a significant condition-by-time interaction among high anhedonic smokers [t(91)= 2.47, p = 0.01] but not among less anhedonic smokers [t(91)= 0.34, p = 0.73].

CONCLUSION

Smoking nicotine vs placebo heightened anhedonic smokers' ability to be induced into a positive mood, whereas nicotine had no effect on more hedonic smokers' positive mood.

Long-term upregulation of protein kinase A and adenylate cyclase levels in human smokers

Repeated injections of cocaine and morphine in laboratory rats cause a variety of molecular neuroadaptations in the cAMP signaling pathway in nucleus accumbens and ventral tegmental area. Here we report similar neuroadaptations in postmortem tissue from the brains of human smokers and former smokers. Activity levels of two major components of cAMP signaling, cAMP-dependent protein kinase A (PKA) and adenylate cyclase, were abnormally elevated in nucleus accumbens of smokers and in ventral midbrain dopaminergic region of both smokers and former smokers. Protein levels of the catalytic subunit of PKA were correspondingly higher in the ventral midbrain dopaminergic region of both smokers and former smokers. Protein levels of other candidate neuroadaptations, including glutamate receptor subunits, tyrosine hydroxylase, and other protein kinases, were within normal range. These findings extend our understanding of addiction-related neuroadaptations of cAMP signaling to tobacco smoking in human subjects and suggest that smoking-induced brain neuroadaptations can persist for significant periods in former smokers.

Fluoxetine, smoking, and history of major depression: A randomized controlled trial

The study was a randomized placebo-controlled trial testing whether fluoxetine selectively enhances cessation for smokers with a history of depression. Euthymic smokers with (H+, n = 109) or without (H-, n = 138) a history of major depression received 60 mg fluoxetine or placebo plus group behavioral quit-smoking treatment for 12 weeks. Fluoxetine initially enhanced cessation for H+ smokers (p = .02) but subsequently impaired cessation regardless of depressive history. Six months after quit date, fluoxetine-treated participants were 3.3 times more likely to be smoking (p = .02). Further research is warranted to determine why high-dose fluoxetine produces continuing effects that oppose tobacco abstinence.

A double-blind placebo controlled experimental study of nicotine: I--effects on incentive motivation

RATIONALE

Brain reward pathways implicated in addiction appear to be less reactive in regular drug users; behavioural manifestations may include decreased sensitivity to natural reinforcers.

OBJECTIVES

This study aimed to replicate earlier findings of abstinence-associated incentive motivation deficits in smokers and to determine whether these can be reversed with nicotine in the form of lozenge.

METHODS

One hundred forty-five smokers were each tested twice, once after receiving nicotine, and once after receiving placebo lozenge in counterbalanced order. Participants completed various tests of incentive motivational functioning: a measure of subjective enjoyment, the Snaith-Hamilton pleasure scale (SHAPS); a simple card sorting task, the card arranging reward responsivity objective test (CARROT) with and without financial incentive; the modified emotional Stroop test; a cue-reactivity task; and a novel reaction time task to explore effects of signals of reward, the incentive motivational enhancement of response speed task.

RESULTS

Compared with performance during abstinence (placebo condition), nicotine was associated with: higher self-reported pleasure expectations on the SHAPS; enhanced responsiveness to financial reward on the CARROT in smokers who smoked 15 or more cigarettes a day; and greater interference from appetitive words on the Stroop task.

CONCLUSIONS

These results are generally consistent with contemporary neurobiological theories of addiction and suggest that short-term smoking abstinence is associated with impaired reward motivation which can be reversed with nicotine.

Nicotine addiction through a neurogenomic prism: ethics, public health, and smoking

Studies are under way to examine the neurogenetic factors contributing to smoking behaviors. The combined approaches of genomics, molecular biology, neuroscience, and pharmacology are expected to fuel developments in pharmacogenetics, to create new genetic tests, and ultimately to provide the basis for innovative strategies for smoking cessation and prevention. The emergence of a neurogenomic understanding of nicotine addiction is likely to induce fundamental changes in popular, clinical, and public health views of smoking, which could significantly shape existing practices and policies to reduce tobacco use. Still a nascent area of research, nicotine addiction provides an excellent case study through which to anticipate key ethical and policy issues in both behavioral genetics and the neurogenomics of addictive behaviors.

Cigarette smoking, ambulatory cardiovascular monitoring, and mood in Vietnam veterans with and without chronic posttraumatic stress disorder

This study investigated the association among cigarette smoking, posttraumatic stress disorder (PTSD), and ambulatory cardiovascular and mood monitoring in 117 male Vietnam combat veterans (61 with PTSD and 56 without PTSD). Positive smoking status was associated with higher systolic blood pressure (SBP) and heart rate (HR), as well as greater diastolic blood pressure (DBP) variability. Compared to individuals without PTSD, PTSD patients had higher HR, anger/hostility ratings, and depression/anxiety ratings. Significant diagnosis by smoking status interactions were found indicating that compared to nonsmokers with PTSD, smokers with PTSD had higher DBP, mean arterial pressure (MAP), and positive affect. Ad lib cigarette smoking during the previous 30 min did not have a significant effect on mood or cardiovascular parameters, except in non-PTSD smokers who reported lower depression/anxiety ratings after smoking. Findings suggest that the effect of smoking on cardiovascular parameters may be amplified in smokers in PTSD. Findings suggest that the interrelationships among cardiovascular parameters, cigarette smoking, and PTSD deserve more research attention.

Cognitive and psychological correlates of smoking abstinence, and predictors of successful cessation

The neural circuitry implicated in addictive drug use, which appears to be down-regulated in early abstinence, corresponds closely with brain reward pathways. A literature review suggests that responses to incentive stimuli and the ability to inhibit reflexive responses, both of which have been associated with normal functioning in these pathways, might be weakened during acute abstinence from chronic drug use. In an ongoing study, 82 smokers, abstinent overnight before two separate testing occasions, have been assessed after administration of nicotine and placebo lozenges (order of sessions counterbalanced). Nicotine administration is associated with a significant reduction in anhedonia, a near-significant increase in response to financial incentive, enhanced ability to inhibit reflexive eye movements, and increased attentional bias to words with appetitive significance. Fifty-nine participants then initiated a quit attempt and 19 reported relapsing within 7 days. Comparing their performance in the two prequit lozenge assessment sessions, relapsers showed a stronger effect of nicotine on enhancing their ability to inhibit reflexive eye movements and a near-significant trend towards greater nicotine-induced increases in attentional bias toward appetitive words.

Alcohol consumption and smoking status: the role of smoking cessation

Cigarette smoking is common among persons with alcohol dependence or abuse with as many as 80% of persons who are alcohol dependent also being smokers. Not only is smoking common in persons with heavy alcohol consumption, but also nicotine dependence appears more severe in smokers with a history of alcohol dependence. This combined exposure to both tobacco smoke and alcohol results in major health consequences including additive risks for some diseases such as head and neck cancers. Although modest alcohol consumption has some positive health benefits, smoking typically negates these benefits. The cellular mechanisms impacted by combined smoking and alcohol exposure are poorly understood, but molecular epidemiology approaches are providing insights regarding the importance of effects on oxidant/antioxidant pathways and on metabolic pathways involving the cytochrome P450 system. Given the prevalence of smoking in the alcohol dependent population, smoking cessation in this group has the potential for tremendous impact. In recent years, smoking cessation approaches have been initiated in this population, but much work remains in order to define the optimal smoking cessation strategies for persons in alcohol treatment programs.

Reverse Selection for Differential Response to the Locomotor Stimulant Effects of Ethanol Provides Evidence for Pleiotropic Genetic Influence on Locomotor Response to Other Drugs of Abuse

BACKGROUND

Addictive drugs share the ability to induce euphoria, which may be associated with their potential for abuse. Replicate mouse lines with high (FAST-1, FAST-2) and low (SLOW-1, SLOW-2) sensitivity to ethanol-induced psychomotor stimulation (a possible animal model for the euphoria experienced by humans) have provided evidence for common genetic influences (pleiotropy) on sensitivity to the effects of ethanol and of GABA-A receptor acting compounds on locomotor activity. Differences between FAST and SLOW mice in locomotor response to certain other drugs were found later in selection. Reverse selection produced lines (r-FAST-1, r-FAST-2, r-SLOW-1, r-SLOW-2) with similar locomotor responses to ethanol. These lines are well suited for asking whether the same alleles that influence sensitivity to ethanol are also responsible for these later arising differences in drug sensitivity.

METHODS

Two replicate sets of forward- and reverse-selected FAST and SLOW lines were tested for the effects of multiple doses of morphine, cocaine, methamphetamine, nicotine, and scopolamine on their locomotor behavior. We predicted that differences in drug sensitivity between the FAST and SLOW lines would be reduced or eliminated in the reverse-selected lines.

RESULTS

Differences in sensitivity to morphine, cocaine, methamphetamine, and nicotine that arose in earlier generations of the FAST-1 and SLOW-1 lines ultimately also appeared in the FAST-2 and SLOW-2 lines. However, some differences between the FAST-2 and SLOW-2 lines (those in response to cocaine and methamphetamine) were not seen until several generations after selection had been relaxed. In lines reverse-selected for sensitivity to ethanol, differences in sensitivity to the other drugs were decreased, eliminated, or even reversed. No differences in scopolamine response were found in the replicate 1 forward- or reverse-selected lines. However, a small difference in scopolamine response in the replicate 2 lines was reversed.

CONCLUSIONS

Genes that influence the locomotor response to ethanol also influence locomotor response to other drugs with stimulant effects in the FAST and SLOW mice. The current data most strongly support this conclusion for sensitivity to morphine and nicotine.

Treatment of nicotine dependence with bupropion SR: review of its efficacy, safety and pharmacological profile

Bupropion hydrochloride, an atypical antidepressant, is the first non-nicotine product that, in its sustained release form (bupropion SR), has been licensed as an aid for smoking cessation. The specialized literature on bupropion SR and smoking cessation is critically reviewed. The pharmacological profile, dosage and administration, contraindications, as well as the clinical efficacy, safety and tolerability data of bupropion are discussed. Recent reports suggest that its mode of actions might be different to what had originally been proposed. When prescribed appropriately, it appears to be a safe, well-tolerated and effective medication in combination with smoking cessation counselling--for a wide range of smokers, as shown in several multicentre double-blind, placebo-controlled clinical trials. Further research is needed on aspects such as the optimal duration of treatment, the potential role of combination therapy with NRT and psychological interventions, and to establish its effectiveness in smokers with other psychiatric disorders or when used with only minimal support by general practitioners.

Cigarette smoking and attention to signals of reward and threat in the Stroop paradigm

AIMS

To test the prediction arising from the incentive-sensitization model of addiction that when tested immediately after smoking, smokers will show heightened attention to words with appetitive and aversive motivational significance compared with their performance during acute abstinence.

DESIGN

Twenty-one smokers were each tested twice, once just after smoking and once after overnight abstinence, on three versions of the modified Stroop task which required colour naming of words with either neutral, appetitive or aversive connotations. Ten non-smokers were tested once.

SETTING

All participants were tested in a quiet experimental cubicle within the psychology department.

PARTICIPANTS

Smokers comprised nine men and 12 women who had smoked at least 10 cigarettes per day for the last 6 months; non-smokers comprised five men and five women who had never smoked. All were aged between 18 and 35 years. Three smokers were excluded from the analyses because their breath CO levels suggested they had not complied with the instructions to abstain on one occasion.

MEASUREMENTS

A card-based, blocked, format was used for the modified Stroop task. Time to colour-name the words of the three motivational types, the order of which was counterbalanced across participants, was recorded.

FINDINGS

Smoking was associated with greater interference from both threat and appetitive words than from neutral words; during abstinence there was no differential effect of word type. Non-smokers performed more similarly to recent smokers.

CONCLUSIONS

This pattern suggests suppression of normal motivational responding during abstinence.

Tobacco and cannabis smoking cessation can lead to intoxication with clozapine or olanzapine

Plasma levels of clozapine and olanzapine are lower in smokers than in nonsmokers, which is mainly due to induction of cytochrome P4501A2 (CYP1A2) by some smoke constituents. Smoking cessation in patients treated with antipsychotic drugs that are CYP1A2 substrates may result in increased plasma levels of the drug and, consequently, in adverse drug effects. Two cases of patients who smoked tobacco and cannabis are reported. The first patient, who was receiving clozapine treatment, developed confusion after tobacco and cannabis smoking cessation, which was related to increased clozapine plasma levels. The second patient, who was receiving olanzapine treatment, showed important extrapyramidal motor symptoms after reducing his tobacco consumption. The clinical implication of these observations is that smoking patients treated with CYP1A2 substrate antipsychotics should regularly be monitored with regard to their smoking consumption in order to adjust doses in cases of a reduction or increase in smoking.

Do risk factors for Alzheimer's disease predict dementia in Parkinson's disease? An exploratory study

The extent to which concomitant Alzheimer's disease (AD) is etiologically related to the development of dementia in Parkinson's disease (PD) remains controversial. We explored the association of four risk factors associated with AD, including head injury, smoking, hypertension, and diabetes mellitus, with incident dementia in PD. A cohort of 180 nondemented PD patients from the Washington Heights community in northern Manhattan, New York, completed a risk factor questionnaire at baseline and was followed annually with neurological and neuropsychological evaluations. The association of baseline variables with incident dementia was analyzed by using Cox proportional hazards models. All analyses controlled for age at baseline, gender, years of education, duration of PD, and total Unified Parkinson's Disease Rating Scale (UPDRS) motor score at baseline. Of 180 patients (mean age, 71.0 +/- 10.3 years), 52 (29%) became demented during a mean follow-up period of 3.6 +/- 2.2 years. Head injury risk ratio ([RR] 0.9; 95% confidence interval [CI], 0.4-2.2; P = 0.9), hypertension (RR, 0.7; 95% CI, 0.4-1.4, P = 0.3), and diabetes mellitus (RR, 0.8; 95% CI, 0.3-2.3; P = 0.7) were not significantly associated with incident dementia in the Cox models. Patients who reported having ever smoked were at increased risk for the development of dementia compared with nonsmokers (RR, 2.0; 95% CI, 1.0-3.9; P = 0.05). Current smoking was significantly associated with incident dementia (RR, 4.5; 95% CI, 1.2-16.4; P = 0.02), whereas past smoking approached significance (RR, 1.9; 95% CI, 0.9-3.7; P = 0.07). Although an inverse association between smoking and PD has been reported in several studies, our study showed a positive association between smoking and dementia in the setting of PD. The association of smoking with incident dementia in PD deserves further study.

Smoking, reward responsiveness, and response inhibition: tests of an incentive motivational model

BACKGROUND

Incentive-motivation models of addiction suggest impairment of functional activity in mesocorticolimbic reward pathways during abstinence. This study tested implications for subjective and behavioral responses to nondrug incentives, cue-elicited craving, and prefrontal cognitive functions, particularly response inhibition.

METHODS

We tested 26 smokers after smoking and after overnight abstinence in counterbalanced order; 26 nonsmokers were also tested twice. Measures included a simple card-sorting test performed with and without financial incentive (the CARROT), the Snaith Hamilton Pleasure Scale as an index of subjective reward responsiveness, ratings of subjective craving and withdrawal before and after exposure to a cigarette, an index of oculomotor response inhibition (saccadic vs. antisaccadic eye movements), verbal fluency, and reversed digit span.

RESULTS

Compared with the smoking condition, and independently of withdrawal severity, abstinence was associated with reduced cue reactivity, pleasure expectancies, responsiveness to financial incentive, and response inhibition (antisaccadic eye movements). Verbal fluency and reversed digit span were unaffected, contrary to findings elsewhere with heavier smokers. Nonsmokers' scores either fell between those of abstainers and recent smokers or approximated those of recent smokers.

CONCLUSIONS

The data were in general consistent with behavioral predictions derived from the incentive-motivational model of addiction and suggest that abstinence may be associated with impairments of motivation and response inhibition, which are independent of other subjectively experienced withdrawal symptoms.

The temporal relationship between emotional distress and cigarette smoking during adolescence and young adulthood

Empirical evidence regarding the causal nature of the relationship between emotional distress and tobacco use in male and female adolescents provides support for both the distress-to-use and the use-to-distress hypotheses. Using a cross-lagged model with 3 waves of data from 2,961 adolescents followed into young adulthood, the authors tested the hypothesis that this relationship changes over time. As hypothesized, emotional distress in Grade 10 was associated with increased smoking in Grade 12 for both boys and girls. Smoking in Grade 12 was in turn associated with increased emotional distress in young adulthood. The addition of 3 third factors (rebelliousness, deviance, and family problems) to the model did not alter the results. Results suggest that the relationship between tobacco use and emotional distress is a dynamic one in which distress initially leads to use but then becomes exacerbated by it over time.

Using nicotine replacement therapy in treating nicotine addiction in adolescents

Cigarette smoking is the greatest cause of preventable death and disability in the United States. More than 3,000 children in the United States begin smoking each day. Smokers experience withdrawal symptoms that can be ameliorated by pharmacological interventions. These interventions include Zyban (Bupropion HCl), Nicorette gum, Habitrol patch, Nicoderm patch, Nicotrol inhaler, and Nicotrol NS spray, along with their generic counterparts. This article reviews each of these agents, the time course of nicotine withdrawal symptoms, and the Fagerstrom Tolerance Questionnaire and presents a framework for assisting the nicotine-addicted student in smoking cessation.

Chronic exposure to nicotine upregulates the human (alpha)4((beta)2 nicotinic acetylcholine receptor function

Widely expressed in the brain, the alpha4beta2 nicotinic acetylcholine receptor (nAChR) is proposed to play a major role in the mechanisms that lead to and maintain nicotine addiction. Using the patch-clamp technique and pharmacological protocols, we examined the consequences of long-term exposure to 0.1-10 micrometer nicotine in K-177 cells expressing the major human brain alpha4beta2 receptor. The acetylcholine dose-response curves are biphasic and revealed both a high- and a low-affinity component with apparent EC(50) values of 1.6 and 62 micrometer. Ratios of receptors in the high- and low-affinity components are 25 and 75%, respectively. Chronic exposure to nicotine or nicotinic antagonists [dihydro-beta-erytroidine (DHbetaE) or methyllycaconitine (MLA)] increases the fraction of high-affinity receptors up to 70%. Upregulated acetylcholine-evoked currents increase by twofold or more and are less sensitive to desensitization. Functional upregulation is independent of protein synthesis as shown by the lack of effect of 20 micrometer cycloheximide. Single-channel currents recorded with 100 nm acetylcholine show predominantly high conductances (38.8 and 43.4 pS), whereas additional smaller conductances (16.7 and 23.5 pS) were observed with 30 micrometer acetylcholine. In addition, long-term exposure to dihydro-beta-erytroidine increases up to three times the frequency of channel openings. These data indicate, in contrast to previous studies, that human alpha4beta2 nAChRs are functionally upregulated by chronic nicotine exposure.

Current concepts in adolescent smoking

This review discusses important research findings regarding adolescent tobacco use reported from April 1999 to March 2000. Although the vast majority of adult smokers began before 1 8 years of age, a significant number of college students seem to be initiating smoking behaviors. Recent literature reviews pointed to cultural as well as neurochemical factors that lead to increased tobacco consumption while creating barriers to quitting. Psychosocial and behavioral correlates of cigarette smoking revealed the role that tobacco use plays in coping with cultural, social, and intrapsychic demands. In addition to understanding why and how adolescents initiate and maintain cigarette smoking, recent studies also attempted to uncover the correlates of quitting behavior. However, recent reports of school-based intervention trials revealed that reproducible, long-term success rates may not be achievable with a single program or approach. Finally, several recent studies explored the role that health care providers play in prevention and intervention, as well as the pitfalls of well-meaning office interventions.