Effects of caffeine consumption on nicotine consumption

Nicotine-induced CREB and DeltaFosB activity is modified by caffeine in the brain reward system of the rat

Coffee and nicotine consumption are frequently combined, indicating possible intensifying effect of caffeine on smoking behavior, although neurobiological background of this phenomenon remains unknown. We aimed at determining the effect of caffeine and nicotine, applied separately or simultaneously, on activation of six structures of the brain reward system: nucleus accumbens (NAc), ventral tegmental area (VTA), amygdala (Amg), hippocampus (Hip), medial prefrontal cortex (mPfr) and dorsal striatum (CdP) in the adult male Wistar rats. Activation of two transcription factors, the phosphorylated form of cyclic AMP-response element binding protein (pCREB) and DeltaFosB (ΔFosB) was assessed by immunohistochemistry after multiple-dose five-days psychostimulants administration followed by 20min and 24h survival, respectively. Nicotine evoked the highest increase of pCREB-immunoreactivity (-ir) in NAc, while caffeine exerted the weakest effect in mPfr and CdP. Nicotine/caffeine co-administration resulted in decrease of pCREB-ir in NAc and increase in Amg, compared with the effect of each psychostimulant used separately. Nicotine was the strongest psychostimulant activating ΔFosB-ir in Amg, whereas caffeine - in Hip. Nicotine/caffeine-exerted effect upon ΔFosB-ir in Amg was weaker, whereas in mPfr stronger, than nicotine-evoked effect in these structures. In summary, pCREB and ΔFosB activation is dependent on the type of stimulus, brain structure and functional context. Activation of both transcription factors is responsible for caffeine's modifying effect upon nicotine-related behaviors and must be taken into account while quitting cigarette smoking.

Does coffee consumption impact on heaviness of smoking?

BACKGROUND AND AIMS

Coffee consumption and cigarette smoking are strongly associated, but whether this association is causal remains unclear. We sought to: (1) determine whether coffee consumption influences cigarette smoking causally, (2) estimate the magnitude of any association and (3) explore potential mechanisms.

DESIGN

We used Mendelian randomization (MR) analyses of observational data, using publicly available summarized data from the Tobacco and Genetics (TAG) consortium, individual-level data from the UK Biobank and in-vitro experiments of candidate compounds.

SETTING

The TAG consortium includes data from studies in several countries. The UK Biobank includes data from men and women recruited across England, Wales and Scotland.

PARTICIPANTS

The TAG consortium provided data on n ≤ 38 181 participants. The UK Biobank provided data on 8072 participants.

MEASUREMENTS

In MR analyses, the exposure was coffee consumption (cups/day) and the outcome was heaviness of smoking (cigarettes/day). In our in-vitro experiments we assessed the effect of caffeic acid, quercetin and p-coumaric acid on the rate of nicotine metabolism in human liver microsomes and cDNA-expressed human CYP2A6.

FINDINGS

Two-sample MR analyses of TAG consortium data indicated that heavier coffee consumption might lead to reduced heaviness of smoking [beta = -1.49, 95% confidence interval (CI) = -2.88 to -0.09]. However, in-vitro experiments found that the compounds investigated are unlikely to inhibit significantly the rate of nicotine metabolism following coffee consumption. Further MR analyses in UK Biobank found no evidence of a causal relationship between coffee consumption and heaviness of smoking (beta = 0.20, 95% CI = -1.72 to 2.12).

CONCLUSIONS

Amount of coffee consumption is unlikely to have a major causal impact upon amount of cigarette smoking. If it does influence smoking, this is not likely to operate via effects of caffeic acid, quercetin or p-coumaric acid on nicotine metabolism. The observational association between coffee consumption and cigarette smoking may be due to smoking impacting on coffee consumption or confounding.

Decision-making style, nicotine and caffeine use and dependence

RATIONALE

As therapeutic interventions are being developed utilising telehealth and mobile phones, it is important to understand how substance-dependent individuals will respond to offers of online assistance.

OBJECTIVES

The present paper considered the following: (1) how decision-making style is associated with use and dependence upon commonly used stimulants and (2) how it influences behavioural responses to electronic offers of further information about these drugs.

METHOD

An online survey examined patterns of nicotine and caffeine use, administered Severity of Dependence Scales for caffeine and nicotine and assessed decision-making style using the Melbourne Decision Making Questionnaire and mood using the Kessler Distress Scale. Upon completing these scales, the 181 participants with a mean age of 28.14 years were offered further information online.

RESULTS

Stimulant dependence was associated with psychological distress. Caffeine dependence was linked to hypervigilance (panic). Decisional self-esteem varied with stimulant dependence and Kessler Distress Scale score. Participants with high decisional self-esteem declined electronic offers of further information.

CONCLUSION

Confidence rather than defensive avoidance was a factor in reducing information-seeking behaviours on the Internet.

Effects of caffeine on persistence and reinstatement of nicotine-seeking behavior in rats: interaction with nicotine-associated cues

RATIONALE

Caffeine and nicotine are the most commonly co-used psychostimulants. However, it is still unclear whether caffeine exposure enhances nicotine-seeking behavior.

OBJECTIVE

The present study examined the effects of caffeine on nicotine-seeking in rats trained to self-administer nicotine with and without presession administration of caffeine.

METHODS

Male Sprague-Dawley rats were trained to intravenously self-administer nicotine (0.03 mg/kg/infusion, freebase) on a fixed ratio 5 schedule of reinforcement and associate a stimulus cue with each nicotine administration. Five minutes before the sessions, the rats received an intraperitoneal administration of caffeine (5 mg/kg). Extinction tests were conducted under four conditions: presession caffeine administration, response-contingent presentation of nicotine cues, neither condition, or both conditions. Reinstatement tests were conducted after responding was extinguished by withholding presession caffeine, nicotine, and its cues. A separate group of rats trained without presession caffeine exposure was also subjected to the reinstatement tests.

RESULTS

In the rats trained with presession caffeine exposure, continued caffeine administration sustained nicotine-seeking responses and interacted with nicotine cues to significantly delay the extinction of nicotine-seeking behavior. Readministration of caffeine after extinction effectively reinstated nicotine-seeking behavior. In caffeine-naive rats, caffeine administration did not reinstate extinguished nicotine-seeking behavior but significantly potentiated the cue-induced reinstatement of nicotine-seeking.

CONCLUSION

These data demonstrate that caffeine administration sustained and reinstated nicotine-seeking behavior, possibly via its acquired discriminative-stimulus properties predictive of nicotine availability. These findings suggest that smokers who attempt to quit may benefit from stopping caffeine consumption.

Do smokers crave cigarettes in some smoking situations more than others? Situational correlates of craving when smoking

INTRODUCTION

Smokers tend to smoke when experiencing craving, but even within smoking occasions, craving may vary. We examine variations in craving when people were smoking in various real-world situations.

METHODS

Using Ecological Momentary Assessment, 394 smokers recorded smoking, craving, and smoking context in real time on electronic diaries over 2 weeks of ad libitum smoking. Assessments occurred immediately prior to smoking. Mixed modeling was used to analyze associations between craving and situational variables.

RESULTS

Craving varied across smoking situations, but the differences were small (<1 on a 0-10 scale). Specifically, craving was higher in smoking situations where smoking was restricted, likely because high craving leads smokers to violate restrictions. Controlling for restrictions, craving was higher when cigarettes were smoked while eating or drinking, were with other people (vs. alone), were in a group of people (vs. other people simply in view), during work (vs. leisure), and during activity (vs. inactivity). In addition, craving was higher for cigarettes smoked early in the day. No differences in craving were observed in relation to drinking alcohol or caffeine (vs. doing anything else), being at work (vs. home), being at a bar or restaurant (vs. all other locations), interacting with others (vs. not interacting), or other people smoking (vs. no others smoking).

DISCUSSION

Even though most craving reports prior to smoking were high, and situations were thus expected to have little influence on craving, results suggest that some cigarettes are craved more than others across different smoking situations, but differences are small.

Caffeine's influence on nicotine's effects in nonsmokers

OBJECTIVE

To determine if nicotine's effects are influenced by caffeine in nonsmoking, moderate-caffeine consuming individuals (N=20).

METHODS

The first 3 sessions included one of 3 randomly ordered, double-blind caffeine doses (0, 75, or 150 mg, oral [po]) and 2 single-blind nicotine gum doses (2 and 4 mg) in ascending order. The fourth session (single blind) repeated the 0 mg caffeine condition.

RESULTS

Nicotine increased heart rate and subjective ratings indicative of aversive effects, and decreased reaction times. These effects were independent of caffeine dose and reliable across sessions.

CONCLUSIONS

In nonsmokers, nicotine effects are not influenced by moderate caffeine doses.

The influence of caffeine on nicotine's discriminative stimulus, subjective, and reinforcing effects

Caffeine may acutely alter the discriminative stimulus and subjective effects of nicotine, perhaps explaining the association of coffee intake with smoking status. In this study, smokers were initially trained to discriminate 20 microg/kg nicotine by nasal spray from placebo (0). Then, generalization of nicotine discrimination was tested, using both 2- and 3-choice ("novel" option) procedures, across a range of doses (0-20 microg/kg) following pretreatment with 0, 2.5, and 5.0 mg/kg caffeine p.o. Nicotine reinforcement was assessed after the end of generalization testing using a choice procedure. Caffeine pretreatment did not alter nicotine discrimination and self-administration. Caffeine and nicotine influenced some subjective and cardiovascular responses, but there were no interaction effects except for diastolic blood pressure. These results do not support the notion that caffeine acutely alters nicotine's discriminative stimulus, subjective, or reinforcing effects.

Immediate antecedents of cigarette smoking: an analysis from ecological momentary assessment

The authors assessed the association between smoking and situational cues, including affect, in real-world contexts. Using ecological momentary assessment, 304 smokers monitored ad-lib smoking for 1 week, recording each cigarette on palm-top computers. Generalized estimating equations contrasted 10,084 smoking and 11,155 nonsmoking situations. After controlling for smoking restrictions, smoking was strongly related to smoking urges and modestly related to consumption of coffee and food, the presence of other smokers, and several activities. Smoking was unrelated to negative or positive affect or to arousal, although it was associated with restlessness. Thus, in daily life, affect appears to exert little influence over ad-lib smoking in heavy smoking adults.

Brain imaging and the effects of caffeine and nicotine

Caffeine and nicotine are the most common psychostimulant drugs used worldwide. Structural neuroimaging findings associated with caffeine and nicotine consumption are limited and primarily reflect the putative relationship between smoking and white matter hyperintensities (WMH), a finding that warrants further appraisal of its clinical implications. The application of newer brain imaging modalities that measure subtle haemodynamic changes or tissue-based chemistry in order to better elucidate brain functional processes, including mechanisms underlying addiction to nicotine and caffeine and the brain functional consequences, provide intriguing findings. Potential influences of caffeine and nicotine on the functional contrast, or metabolic response, to neural activation also necessitates the careful appraisal of the effects that these commonly used drugs may have on the results of functional imaging.

Alteration of the behavioral effects of nicotine by chronic caffeine exposure

The prevalence of tobacco smoking and coffee drinking place nicotine and caffeine among the most used licit drugs in many societies and their consumption is often characterised by concurrent use. The pharmacological basis for any putative interaction between these drugs remains unclear. Some epidemiological reports support anecdotal evidence, which suggests that smokers consume caffeine to enhance the effects of nicotine. This paper reviews various aspects of the pharmacology of caffeine and nicotine, in humans and experimental animals, important for the understanding of the interactions between these drugs. In particular, recent experiments are reviewed in which chronic exposure to caffeine in the drinking water of rats facilitated acquisition of self-adminstration behavior, enhanced nicotine-induced increases in dopamine levels in the shell of the nucleus accumbens and altered the dopaminergic component of a nicotine discrimination. These studies provide evidence that the rewarding and subjective properties of nicotine can be changed by chronic caffeine exposure and indicate that caffeine exposure may be an important environmental factor in shaping and maintaining tobacco smoking.

The effect of ephedrine plus caffeine on smoking cessation and postcessation weight gain

OBJECTIVES

To evaluate the efficacy of a combination of ephedrine and caffeine on smoking cessation rates, postcessation weight gain, and withdrawal symptoms and to examine changes in glycosylated hemoglobin (HbA1c) after smoking cessation.

METHODS

This randomized double-blind placebo-controlled study with a 1-year follow-up period was carried out at the Department of Pulmonary Medicine in Denmark. Study subjects were 225 heavy smokers who wanted to quit smoking without gaining weight. Two-thirds of the subjects were randomized to receive 20 mg ephedrine plus 200 mg caffeine three times a day; one-third of the subjects received placebo treatment. The dosage was gradually decreased from week 12 to discontinuation at week 39. Group support and control were performed at entry and after 1, 3, 6, 12, 26, 39, and 52 weeks. Main outcome measures were (1) self-reported abstinence with validation by carbon monoxide in expired air and serum cotinine and (2) weight gain.

RESULTS

The success rates after 1 year were 17% in the group treated with ephedrine plus caffeine and 16% in the group treated with placebo; the success rates were not significantly different at any time. The success rates for the four counseling physicians varied between 7% and 27% after 1 year (p < 0.05). The weight gain was significantly lower in the ephedrine plus caffeine-treated group during the first 12 weeks, but weight gains were similar after 1 year. No differences in the smoking withdrawal symptoms could be observed between the treatment groups. HbA1c was lower 6 weeks and 1 year after smoking cessation (p < 0.05).

CONCLUSIONS

We found an effect of this combination of ephedrine and caffeine on weight gain during the first 12 weeks, but we found no effect on the success rates or craving for cigarettes.

Caffeine and smoking: subjective, performance, and psychophysiological effects

The effects of caffeine and smoking on cognitive performance, subjective variables, heart rate, and EEG were assessed in two sessions. In one session, subjects received caffeine (2.5 mg/kg bodyweight), while in the other they received placebo. In both sessions they smoked a cigarette (8 cued puffs) having a nicotine yield of 1.2 mg. Caffeine produced an increase in self-reported muscular tension and tended to increase anxiety and delta magnitude. Smoking facilitated performance of a paper-and-pencil math task and increased heart rate. Smoking also appeared to produce cortical activation as indexed by decreased right frontal delta, decreased right centro-parietal theta, globally increased alpha, and increased centro-occipital/decreased posterior-temporal beta 1. Smoking also increased central/decreased posterior-temporal beta 2. Smoking and caffeine did not interact for any measure, suggesting that the epidemiological link between smoking and coffee drinking may have a non-pharmacological basis.

Caffeine and nicotine: a review of their joint use and possible interactive effects in tobacco withdrawal

There is a strong, significant relationship between coffee consumption and smoking. In six epidemiological studies reviewed and analyzed here, 86.4% of smokers consumed coffee versus 77.2% of nonsmokers. Exsmokers use more coffee than nonsmokers but somewhat less than smokers. Seventeen experimental studies suggest that the pharmacologic effect of caffeine in coffee may be partially but not totally responsible for the relationship. Conditioning, a reciprocal interaction (caffeine intake increases anxiety/arousal--nicotine decreases it), or joint effect of a third variable (e.g., stress, alcohol) may account for the relationship. In abstinent smokers, blood caffeine levels increase and remain elevated for as long as 6 months. These higher caffeine plasma levels may be sufficient to produce caffeine toxicity syndrome. A review of 86 studies of nicotine withdrawal, caffeine withdrawal, and caffeine toxicity suggests that the symptoms are similar enough to be confused, and that reported nicotine withdrawal symptoms may be a mixture of nicotine withdrawal and caffeine toxicity.

Caffeine antagonizes EEG effects of tobacco withdrawal

Six current cigarette smokers and coffee drinkers were given combinations of 0, 150, or 300 mg caffeine and 0, 2, or 4 mg nicotine polacrilex following 12-h nicotine and caffeine abstinence. On one study day, subjects were allowed to smoke cigarettes and to drink caffeinated beverages and no drugs were given. Tobacco and caffeine abstinence impaired performance on the serial addition/subtraction and digit recall tasks; decreased scores on the MBG scale and ratings of "clear-headed" and "quick-witted"; and increased ratings of "irritability," "muscular tension," "headache," "drowsy," "clumsy," "feeble," and "dreamy." The deprivation caused characteristic EEG signs of nicotine withdrawal including increased theta power and decreased alpha frequency. These EEG effects were reversed by cigarette smoking and caffeine administration, but nicotine polacrilex was less effective. Deprivation-induced performance and subjective measures were not changed by administration of nicotine and caffeine combinations.

Patterns of alcohol, cigarette, and caffeine and other drug use in two drug abusing populations

Relationships were explored among the frequencies of use of various drugs by a sample of drug-abusing clients of the Addiction Research Foundation (ARF) in Toronto and by drug abusers volunteering to participate in research at the Addiction Research Center (ARC) in Baltimore. The two groups of drug-abusing individuals differed in a number of characteristics. Those from ARF were admitted primarily for diagnosis and possible treatment for alcohol and non-opioid drug problems, whereas those from the ARC were admitted for participation in research on other drugs of abuse, primarily involving opioids. Patterns of use of certain drugs tended to covary in both groups. Of particular interest was the finding that severity of alcoholism was directly related to various measures of tobacco and caffeinated beverage use. In contrast, there was little correlation between the frequency of use among other drugs of abuse (e.g., heroin, cannabis, glue) and the use of tobacco and caffeine. These findings suggest that dependence on nicotine, caffeine, and alcohol may be governed by the same factors and possibly should be considered jointly in the treatment of alcoholic persons. Frequency of use of other drugs examined may be controlled by other factors than those which determine level of use of tobacco and caffeine.

Stimulant drugs and vigilance performance: a review

The literature on the effects of some stimulant drugs (amphetamine, methylphenidate, caffeine, and nicotine) on vigilance performance is reviewed. Improvement of overall level of performance (both accuracy and speed) after the intake of amphetamine, caffeine, and nicotine has often been reported, and the decrement in performance with time has been shown to be prevented especially with amphetamine and nicotine. Effects on false alarms are negligible. In studies where a test battery was employed, vigilance tasks appeared to be the most sensitive performance tests in detecting the effects of stimulants; however, different vigilance tasks may measure different aspects of mental functions. There is no support for earlier conclusions that improvements are noticed only in fatigued subjects in protracted sessions. Evidence from several studies does not support the hypothesis that improvements are only a recovery of withdrawal-induced impairment. Because positive effects have been obtained with drugs possessing different mechanisms of action, there is as yet no clear support for a noradrenergic, dopaminergic, or cholinergic theory of sustained attention. Simple neurotransmitter theories of attention and information processing may be untenable.

Caffeine and the central nervous system: mechanisms of action, biochemical, metabolic and psychostimulant effects

Caffeine is the most widely consumed central-nervous-system stimulant. Three main mechanisms of action of caffeine on the central nervous system have been described. Mobilization of intracellular calcium and inhibition of specific phosphodiesterases only occur at high non-physiological concentrations of caffeine. The only likely mechanism of action of the methylxanthine is the antagonism at the level of adenosine receptors. Caffeine increases energy metabolism throughout the brain but decreases at the same time cerebral blood flow, inducing a relative brain hypoperfusion. Caffeine activates noradrenaline neurons and seems to affect the local release of dopamine. Many of the alerting effects of caffeine may be related to the action of the methylxanthine on serotonin neurons. The methylxanthine induces dose-response increases in locomotor activity in animals. Its psychostimulant action on man is, however, often subtle and not very easy to detect. The effects of caffeine on learning, memory, performance and coordination are rather related to the methylxanthine action on arousal, vigilance and fatigue. Caffeine exerts obvious effects on anxiety and sleep which vary according to individual sensitivity to the methylxanthine. However, children in general do not appear more sensitive to methylxanthine effects than adults. The central nervous system does not seem to develop a great tolerance to the effects of caffeine although dependence and withdrawal symptoms are reported.

Psychophysiological interactions between caffeine and nicotine

The interactive effects of caffeine and nicotine were studied in twelve subjects. Mood and physiologic responses to the pharmacologic components nicotine and caffeine were measured, while controlling for the sensory/behavioral aspects of smoking and coffee drinking. Two experimental sessions presented a caffeine x nicotine design, with caffeinated or decaffeinated coffee followed at thirty-minute intervals by controlled inhalations of nicotine and nonnicotine smoke. Results showed that there was a significant interactive effect of caffeine and nicotine on subjective arousal such that nicotine decreased arousal only in the presence of caffeine. These findings extend previous work showing interactive effects of caffeine and self-titrated doses of cigarette smoke in affecting subjective arousal. The effects of nicotine on subjective arousal may, therefore, depend not only on nicotine dose, but also on the presence of caffeine. Heart rate was increased by nicotine and both systolic and diastolic blood pressures were elevated by caffeine. Caffeine also potentiated the increase in diastolic blood pressure resulting from smoke inhalations, but this occurred irrespective of nicotine dose.

Caffeine and cigarette smoking: behavioral, cardiovascular, and metabolic interactions

Coffee drinking and cigarette smoking are strongly correlated behaviors which have been suggested to act synergistically to produce adverse health consequences, particularly coronary heart disease (CHD). We studied in smokers the influence of four days of multiple daily doses of coffee containing different doses or no caffeine on cigarette smoking behavior, nicotine intake from smoking, heart rate and blood pressure, circadian serum glucose, and urinary catecholamine excretion. We observed a tendency toward greater cigarette consumption during caffeine consumption, and a tendency toward higher plasma nicotine levels during low-dose caffeine compared with the no-caffeine condition; however, these effects were small. No caffeine effects on any other of the above parameters were observed. Previously published research has usually studied effects of single doses of caffeine, which does not account for development of tolerance to effects of caffeine. If caffeine does contribute to CHD risk, it is not likely to be related to caffeine effects on smoking behavior, nicotine intake, blood pressure, heart rate, glucose tolerance, or catecholamine release. Adverse effects of long-term caffeine consumption on lipids cannot be excluded.

Pharmacological treatment of tobacco dependence

Pharmacologically based approaches for the treatment of tobacco dependence are reviewed. The rational basis for pharmacologic treatment approaches is that tobacco dependence is partially, and critically, mediated by the actions of tobacco-delivered nicotine to the central nervous system. These actions include direct reinforcing properties of nicotine itself, tolerance and physiologic dependence, possible beneficial effects of nicotine in the alleviation of anxiety and control of weight, and neurohormonal regulation which can become important to the maintenance of emotional well-being and performance at work. Insofar as tobacco abstinence leads to negative consequences, via these biobehavioral mechanisms, pharmacologic intervention should be able to assist in initial tobacco detoxification and help tobacco abstinent persons to avoid subsequent relapse. The purpose of this review is to survey some of the efforts to develop such interventions, as well as to elucidate some of the issues relevant to such development. Four distinct approaches are discussed: (1) Nicotine replacement, in which physiologic dependence is transferred to a safer and more therapeutically manageable nicotine delivering formulation; this category includes nicotine polacrilex gum; (2) Blockade therapy, in which a drug is taken that blocks the reinforcing properties of nicotine should relapse occur; (3) Nonspecific pharmacotherapy, in which the biobehaviorally mediated correlates of tobacco abstinence are treated on a symptomatic basis; (4) Deterrent therapy, in which a drug is taken prior to smoking such that any tobacco use would produce reliable aversive effects.

Effects of marijuana smoking on subjective ratings and tobacco smoking

Multiple measures of tobacco cigarette smoking and subjective and physiological effect were collected during 90 minute test sessions in volunteer cigarette smokers who also had histories of recreational marijuana use. Before sessions, subjects smoked one marijuana cigarette (placebo or 1.29%, 2.84%, 4.00%) using a standardized puffing procedure. Each dose and placebo was given four times to each subject in a randomized block sequence. Marijuana smoking produced dose-related increases in heart rate, ratings of dose strength and drug liking. However, marijuana produced no significant alterations in tobacco cigarette smoking. Puff duration within each marijuana cigarette varied in a fashion similar to that observed in previous studies of tobacco cigarette smoking: puff duration progressively decreased as the cigarette was smoked. This effect is probably due to progressive decreases in resistance to draw as the cigarette is smoked. Expired air carbon monoxide (CO) levels following marijuana smoking were inversely related to marijuana dose, suggesting the occurrence of some compensatory changes in marijuana smoking in response to dose manipulations. It is concluded that, although marijuana produces dose-related effects on physiological and subjective effects and on marijuana smoking behavior, marijuana differs from a variety of other psychoactive drugs previously studied in this paradigm in that no reliable changes in tobacco smoking were produced.

Nicotine and caffeine effects on the task-elicited blood pressure response

Nine subjects participated in four daily sessions during which a psychomotor task was performed prior to and following drug administration. Blood pressure was reliably increased by task performance, cigarette smoking, and caffeine administration. The effect of the combination of task performance, cigarette smoking and caffeine administration was additive, resulting in a markedly increased blood pressure during task performance for subjects smoking cigarettes and receiving caffeine.

Buprenorphine effects on cigarette smoking

Cigarette smoking increased during administration of buprenorphine, an opioid mixed agonist-antagonist, in comparison to drug-free baseline in seven heroin addicts maintained on buprenorphine for 24 days (P less than 0.01-0.001). Ascending buprenorphine doses (0.5 - 8.0 mg/day) were associated with significant increases in cigarette smoking at doses of 2.0 mg/day sc and above. Cigarette smoking during 10 days of buprenorphine maintenance at 8 mg/day was significantly higher than during the buprenorphine induction phase (P less than 0.01). Six subjects given placebo buprenorphine over 14 days showed no change in cigarette smoking. The placebo group self-administered heroin for 10 days, and cigarette smoking increased significantly during heroin use (P less than 0.001). The rate of cigarette smoking defined by intercigarette intervals was highest during the 10 days of high-dose buprenorphine maintenance or placebo plus heroin self-administration. Both groups requested significantly more cigarettes at intervals of 0-10, 11-20, and 21-30 min than during the drug-free baseline. These data confirmed previous findings that opioid agonist administration is associated with increased cigarette smoking and suggest that buprenorphine has primarily agonist effects on cigarette smoking.

Effects of single doses of alcohol and caffeine on cigarette smoke puffing behavior

Puffing behavior (number of puffs, puff duration, puff volume, peak pressure, peak flow, peak latency, and puff interval) and pre- to postsmoking delta tidal CO difference were measured in female subjects in order to assess separate and combined effects of ethanol and caffeine. The subjects smoked two cigarettes of their habitual brand in a preliminary familiarizing session and in each of the subsequent four test sessions. The treatments administered after smoking the first cigarette in the test sessions were: alcohol placebo and caffeine placebo; alcohol placebo and caffeine; alcohol and caffeine placebo; alcohol and caffeine. Test-retest reliability across the first cigarette of each session (which was not smoked under the influence of the treatments) was remarkably high for all the puffing parameters. Ethanol in the dose of 0.7 g/kg intensified cigarette smoking of the second cigarette by increasing delta tidal CO, average puff volume, and total puff volume per cigarette, whereas 0.5 g/kg ethanol and 5 mg/kg caffeine given alone or combined with ethanol failed to influence puffing behavior consistently.

The effect of d-amphetamine and ephedrine on smoking attitude and behavior

Using a double blind, randomized, latin square design, 17 light smokers and 6 heavy smokers were given three times per day doses of placebo, 5 mg amphetamine sulfate, 7.5 mg amphetamine sulfate, 25 mg ephedrine hydrochloride or 50 mg ephedrine hydrochloride. Compared to placebo, active drug produced a statistically significant drop in feeling of addiction to cigarettes (p = 0.022). Ephedrine was reported to be more effective than amphetamine (p = 0.046). Subjects reported similar changes in feeling of enjoyment of smoking. Active drug produced a statistically significant drop in the actual amount of tobacco smoked in heavy smokers (p = 0.028), but not in light smokers. Only two smokers were able to quit completely during the experiment, and one of those people resumed smoking after she stopped taking medication. Possible explanations of these findings are discussed.

Caffeine and human behavior: arousal, anxiety, and performance effects

A review of the recent literature shows the role of caffeine in the physiology, mood, and behavior of persons to be a complex one including changes in arousal, anxiety, and performance. Questions are raised as to what degree the physiological effects of caffeine are due to central nervous system stimulation and/or result from the release of catecholamines. Anxiety resulting from both high levels of caffeine (caffeinism) and caffeine withdrawal plus an association between caffeine and depression are discussed. Performance effects are mixed, with both increases and decreases reported. Effects on mental tasks are related to personality variables. The possible role of differences in initial sensitivity, adaptation to caffeine, and/or interactions with nicotine and alcohol is discussed. The present paper reviews these studies, discusses their implications for both clinical and experimental work, summarizes the major unresolved issues, and makes suggestions for new and continuing areas of research.

Event time-series relationship between cigarette smoking and coffee drinking

Eight subjects resided in a programmed laboratory environment for seven to twelve successive days during which time cigarettes and coffee were freely available. An event time-series analysis based upon instances in time of each substance's use revealed a relationship between cigarette smoking and coffee drinking: a coffee-drinking event tended to occur late in the inter-cigarette interval, and a cigarette-smoking event was most probable during the twenty minutes immediately following a coffee-drinking event.

[Reciprocal action between caffeine, other stimulants and drugs]

Caffeine is ingested not only with beverages as coffee, tea, coca-cola but also in form of many analgetic drugs. Therefore interactions of this substance with other biologically active substances and drugs should be expected, and the knowledge of these would be of practical importance. The interactions between caffeine and alcohol, smoking, salicylic acid, phenacetin, barbiturates, and theobromine are described.

The misuse of 'less-hazardous' cigarettes and its detection: hole-blocking of ventilated filters

Smokers of low-yield, ventilated-filter cigarettes sometimes defeat the purpose of the smoke-dilution holes by occluding them with fingers, lips, or tape. Blocking the holes is shown to have large effects on the delivery by these cigarettes of toxic products (nicotine, tar, and carbon monoxide). Techniques for detecting this misuse of "less hazardous" cigarettes are discussed, with particular emphasis on the distinctive signs of hole-blocking which are left in the spent filters.

Indulgence, Excess, and Restraint: Perspectives on Consummatory Behavior in Everyday Life

A regulatory model of consumption is outlined, with an emphasis on upper and lower regulatory limits which govern consumption. We argue that aversive physiological symptoms counteract failure to maintain consumption within regulatory limits, but that consumption within these limits is affected by various situational and cognitive factors. This model is applied to the consumption of food, alcohol, tobacco, and caffeine, with particular attention to the distinctive features of regulation that pertain to each. Implications are derived regarding the multiple meanings of “excessive”and “insufficient” consumption in this framework. We also discuss the relative (perceived) contributions of physiological and “personal” mechanisms of regulatory control and ensuing effects of self-perception and attribution. Concluding remarks concern the complexities of multiple substance use.