Effects of moderate-dose treatment with varenicline on neurobiological and cognitive biomarkers in smokers and nonsmokers with schizophrenia or schizoaffective disorder

CONTEXT

The administration of nicotine transiently improves many neurobiological and cognitive functions in schizophrenia and schizoaffective disorder. It is not yet clear which nicotinic acetylcholine receptor (nAChR) subtype or subtypes are responsible for these seemingly pervasive nicotinic effects in schizophrenia and schizoaffective disorder.

OBJECTIVE

Because α4β2 is a key nAChR subtype for nicotinic actions, we investigated the effect of varenicline tartrate, a relatively specific α4β2 partial agonist and antagonist, on key biomarkers that are associated with schizophrenia and are previously shown to be responsive to nicotinic challenge in humans.

DESIGN

A double-blind, parallel, randomized, placebo-controlled trial of patients with schizophrenia or schizoaffective disorder to examine the effects of varenicline on biomarkers at 2 weeks (short-term treatment) and 8 weeks (long-term treatment), using a slow titration and moderate dosing strategy for retaining α4β2-specific effects while minimizing adverse effects.

SETTING

Outpatient clinics.

PARTICIPANTS

A total of 69 smoking and nonsmoking patients; 64 patients completed week 2, and 59 patients completed week 8. Intervention Varenicline.

MAIN OUTCOME MEASURES

Prepulse inhibition, sensory gating, antisaccade, spatial working memory, eye tracking, processing speed, and sustained attention.

RESULTS

A moderate dose of varenicline (1) significantly reduced the P50 sensory gating deficit in nonsmokers after long-term treatment (P = .006), (2) reduced startle reactivity (P = .02) regardless of baseline smoking status, and (3) improved executive function by reducing the antisaccadic error rate (P = .03) regardless of smoking status. A moderate dose of varenicline had no significant effect on spatial working memory, predictive and maintenance pursuit measures, processing speed, or sustained attention by Conners' Continuous Performance Test. Clinically, there was no evidence of exacerbation of psychiatric symptoms, psychosis, depression, or suicidality using a gradual titration (1-mg daily dose).

CONCLUSIONS

Moderate-dose treatment with varenicline has a unique treatment profile on core schizophrenia-related biomarkers. Further development is warranted for specific nAChR compounds and dosing and duration strategies to target subgroups of schizophrenic patients with specific biological deficits.

Relative performance of common biochemical indicators in detecting cigarette smoking

AIMS

Many cities have banned indoor smoking in public places. Thus, an updated recommendation for a breath carbon monoxide (CO) cut-off is needed that optimally determines smoking status. We evaluated and compared the performance of breath CO and semiquantitative cotinine immunoassay test strips (urine and saliva NicAlert®) alone and in combination.

DESIGN

Cross-sectional study.

SETTING

Urban drug addiction research and treatment facility.

PARTICIPANTS

Ninety non-treatment-seeking smokers and 82 non-smokers.

MEASUREMENTS

Participants completed smoking histories and provided breath CO, urine and saliva specimens. Urine and saliva specimens were assayed for cotinine by NicAlert® and liquid chromatography-tandem mass spectrometry (LCMSMS).

FINDINGS

An optimal breath CO cut-off was established using self-report and LCMSMS analysis of cotinine, an objective indicator, as reference measures. Performance of smoking indicators and combinations were compared to the reference measures. Breath CO ≥5 parts per million (p.p.m.) optimally discriminated smokers from non-smokers. Saliva NicAlert® performance was less effective than the other indicators.

CONCLUSIONS

In surveys of smokers and non-smokers in areas with strong smoke-free laws, the breath carbon monoxide cut-off that discriminates most effectively appears to be ≥5 p.p.m. rather than the ≥10 p.p.m. cut-off often used. These findings may not generalize to clinical trials, regions with different carbon monoxide pollution levels or areas with less stringent smoke-free laws.

Tobacco craving in smokers with and without schizophrenia

We examined tobacco craving and dependence in current smokers (18-65 years) with schizophrenia (N=100) and those without a psychiatric disorder (normal controls, N=100). During the 2-3h visit participants completed demographic and smoking-related questionnaires and provided a breath CO sample. The Tobacco Craving Questionnaire-Short Form (TCQ-SF) was administered. Immediately after smoking one cigarette, no difference in TCQ-SF total score was noted (46.7±19.5 schizophrenia, 42.8±18.2 controls, p=0.15); however, after 15 min TCQ-SF total score was significantly higher in people with schizophrenia (50.0±19.6) than in controls (38.6±19.4) (p=0.0014). TCQ-SF factors of emotionality (p=0.0015), compulsivity (p=0.0003) and purposefulness (p=0.0174) were significantly greater in the schizophrenia group than the control group. FTND scores (5.5±2.0 vs 5.3±2.0, p=0.62) number of cigarettes smoked daily (17.9±11.6 vs. 17.0±7.9), expired breath CO (28.0±14.5 ppm vs. 22.0±8.0 ppm) and age at smoking initiation (16.2±5.4 vs. 15.6±5.5 years, p=0.44) did not differ in the schizophrenia and control groups respectively. In conclusion, tobacco craving as measured by the TCQ-SF was significantly greater in people with schizophrenia than controls 15 min post-smoking, despite similar scores in dependence and similar smoking histories and current smoking patterns.

Sociodemographic characteristics of cannabis smokers and the experience of cannabis withdrawal

BACKGROUND

Cannabis withdrawal can be a negative reinforcer for relapse, but little is known about its association with demographic characteristics.

OBJECTIVES

Evaluate the association of demographic characteristics with the experience of cannabis withdrawal.

METHODS

Retrospective self-report of a "serious" cannabis quit attempt without formal treatment in a convenience sample of 104 non-treatment-seeking, adult cannabis smokers (mean age 35 years, 52% white, 78% male) with no other current substance use disorder (except tobacco) or chronic health problems. Reasons for quitting, coping strategies to help quit, and 18 specific withdrawal symptoms were assessed by questionnaire.

RESULTS

Among withdrawal symptoms, only anxiety, increased sex drive, and craving showed significant associations with age, race, or sex. Women were more likely than men to report a physical withdrawal symptom (OR = 3.2, 95% CI = .99-10.4, p = .05), especially upset stomach. There were few significant demographic associations with coping strategies or reasons for quitting.

CONCLUSIONS AND SCIENTIFIC SIGNIFICANCE

This small study suggests that there are few robust associations between demographic characteristics and cannabis withdrawal. Future studies with larger samples are needed. Attention to physical withdrawal symptoms in women may help promote abstinence.

Meta-analysis of the acute effects of nicotine and smoking on human performance

RATIONALE AND OBJECTIVE

Empirical studies indicate that nicotine enhances some aspects of attention and cognition, suggesting a role in the maintenance of tobacco dependence. The purpose of this review was to update the literature since our previous review (Heishman et al. Exp Clin Psychopharmacol 2:345-395, 1994) and to determine which aspects of human performance were most sensitive to the effects of nicotine and smoking.

METHODS

We conducted a meta-analysis on the outcome measures of 41 double-blind, placebo-controlled laboratory studies published from 1994 to 2008. In all studies, nicotine was administered, and performance was assessed in healthy adult nonsmokers or smokers who were not tobacco-deprived or minimally deprived (

RESULTS

There were sufficient effect size data to conduct meta-analyses on nine performance domains, including motor abilities, alerting and orienting attention, and episodic and working memory. We found significant positive effects of nicotine or smoking on six domains: fine motor, alerting attention-accuracy and response time (RT), orienting attention-RT, short-term episodic memory-accuracy, and working memory-RT (effect size range = 0.16 to 0.44).

CONCLUSIONS

The significant effects of nicotine on motor abilities, attention, and memory likely represent true performance enhancement because they are not confounded by withdrawal relief. The beneficial cognitive effects of nicotine have implications for initiation of smoking and maintenance of tobacco dependence.

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Key Words

• nicotine
• tobacco
• smoking
• performance
• motor
• attention
• memory
• cognition
• smokers
• nonsmokers

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MESH Headings

• Attention/drug effects
• Dose-Response Relationship, Drug
• Humans
• Memory/drug effects
• Motor Skills/drug effects
• Nicotine/administration & dosage
• Nicotine/pharmacology
• Psychomotor Performance/drug effects
• Smoking/psychology

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Grants

• T32 DA007209 NIDA NIH HHS
• ZIA DA000483-06 Intramural NIH HHS
• ZIA DA000484-06 Intramural NIH HHS
• T32DA007209-29 NIDA NIH HHS

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Prolonged duration of craving, mood, and autonomic responses elicited by cues and imagery in smokers: Effects of tobacco deprivation and sex

Increases in self-reported craving and changes in autonomic functioning are reliably elicited when smokers are exposed to tobacco-related stimuli compared with neutral stimuli. However, few studies have reported the time course of cue-elicited craving or have directly compared the effectiveness of smoking cues versus imagery to evoke a craving response. In addition to these two issues, we investigated the influence of tobacco deprivation and sex on craving, mood, and autonomic responses. Sixty cigarette smokers (30 men, 30 women) were tested in two counterbalanced sessions, one after overnight tobacco deprivation and one during ad libitum smoking. At each session, participants were exposed to four randomized experimental trials: smoking imagery, neutral imagery, smoking cues, and neutral cues. Tobacco craving and mood were assessed repeatedly and physiological measures were recorded continuously for 30 min after imagery or cue exposure. Compared with neutral trials, smoking cues and smoking imagery reliably increased tobacco craving, negative mood, heart rate, and blood pressure and decreased positive mood ratings. Changes were observed immediately after cue and imagery presentation and remained unchanged for 30 min. Responding was greater in the nondeprived condition, and cues elicited more robust responding than imagery for most measures. Women responded more robustly to smoking cues only in the nondeprived condition, whereas imagery evoked greater responses in men during both conditions. These findings provide new data on the time course, magnitude, and tobacco deprivation effects on elicited craving. Sex differences were dependent on stimulus type and deprivation condition.

Tobacco, cocaine, and heroin: Craving and use during daily life

BACKGROUND

Relationships among tobacco smoking, tobacco craving, and other drug use and craving may have treatment implications in polydrug-dependent individuals.

METHODS

We conducted the first ecological momentary assessment (EMA) study to investigate how smoking is related to other drug use and craving during daily life. For up to 20 weeks, 106 methadone-maintained outpatients carried PalmPilots (PDAs). They reported their craving, mood, behaviors, environment, and cigarette-smoking status in 2 to 5 random-prompt entries/day and initiated PDA entries when they used cocaine or heroin or had a discrete episode of craving for cocaine or heroin.

RESULTS

Smoking frequency increased linearly with random-prompt ratings of tobacco craving, cocaine craving, and craving for both cocaine and heroin. Smoking frequency was greater during discrete episodes of cocaine use and craving than during random-prompt reports of low craving for cocaine. This pattern was also significant for dual cocaine and heroin use and craving. Smoking and tobacco craving were each considerably reduced during periods of urine-verified abstinence from cocaine, and there was a (nonsignificant) tendency for morning smoking to be especially reduced during those periods.

CONCLUSIONS

This EMA study confirms that smoking and tobacco craving are strongly associated with the use of and craving for cocaine and heroin. Together with prior findings, our data suggest that tobacco and cocaine may each increase craving for (and likelihood of continued use of) themselves and each other. Treatment for tobacco dependence should probably be offered concurrently with (rather than only after) initiation of treatment for other substance-use disorders.

Validity of the 12-item French version of the Tobacco Craving Questionnaire in treatment-seeking smokers

INTRODUCTION

The French version of the Tobacco Craving Questionnaire (FTCQ) is a valid and reliable 47-item self-report instrument that assesses tobacco craving in four factors: emotionality, expectancy, compulsivity, and purposefulness. For use in research and clinical settings, we constructed a 12-item version of the FTCQ (FTCQ-12).

METHOD

The FTCQ-12 was administered to treatment-seeking French smokers (n = 310) enrolled in the Adjustment of DOses of NIcotine in Smoking Cessation (ADONIS) trial. We conducted confirmatory factor analysis (CFA) and examined congruence in factor loadings between the FTCQ and FTCQ-12 to determine the validity and reliability of the FTCQ-12. Measures of tobacco craving, withdrawal, smoking patterns, and smoking history were included to explore the concurrent validity of the FTCQ-12. We used craving scores to distinguish participants who were highly dependent on nicotine from those less dependent on nicotine.

RESULTS

CFA indicated excellent fit for a four-factor model, with congruence coefficients indicating moderate similarity in factor patterns and loadings between the FTCQ and FTCQ-12. Individual factors of the FTCQ-12 correlated positively with smoking history and withdrawal variables. Participants who were highly dependent on nicotine were nearly six times more likely to score >5 on the General Craving Score (maximum: 7) than those less dependent on nicotine.

DISCUSSION

Findings suggest that the FTCQ-12 measures the same four factors as the FTCQ and TCQ, and these four constructs have unique properties. The FTCQ-12 yields valid and reliable indices of tobacco craving and has potential clinical utility for rapid assessment of tobacco craving in smokers seeking treatment.

Puffing behavior during the smoking of a single cigarette in tobacco-dependent adolescents

INTRODUCTION

Adult and adolescent smokers regulate their nicotine and smoke intake by smoking low-yield cigarettes more intensely than high-yield cigarettes. One likely mechanism of nicotine regulation is altered puffing topography, which has been demonstrated in adult smokers. The purpose of this study was to examine the pattern of puffing behavior during the smoking of a single cigarette in adolescents.

METHODS

Tobacco-dependent adolescents (n = 89) were enrolled in a treatment trial testing the efficacy of nicotine replacement therapy. About 1 week before their quit date, participants smoked ad libitum one of their usual brand of cigarettes during a laboratory session. Smoking topography measures included puff volume, puff duration, puff velocity, and interpuff interval.

RESULTS

Controlling for sex, race, and number of puffs, puff volume and puff duration decreased 12.8% and 24.5%, respectively, from the first 3 to the last 3 puffs. Puff velocity and interpuff interval increased 14.8% and 13.5%, respectively. Puff volume was positively correlated with puff duration and puff velocity, whereas puff duration and puff velocity were negatively correlated. However, none of the topography measures were correlated with smoking history variables.

DISCUSSION

These results suggest that adolescent smokers, like adults, are able to regulate smoke and nicotine intake on a puff-by-puff basis, therefore indicating that this aspect of smoking control is acquired early in the tobacco-dependence process.

Breath carbon monoxide and semiquantitative saliva cotinine as biomarkers for smoking

OBJECTIVE

As a biomarker of smoking, semiquantitative analysis of cotinine (NicAlert) offers several advantages over breath carbon monoxide (CO) and quantitative analysis of cotinine. Recent studies have used urine NicAlert and breath CO in combination to verify abstinence. However, no studies have evaluated the performance of saliva NicAlert against or in combination with breath CO.

METHOD

Breath CO, saliva NicAlert, and smoking history were compared in an urban population of daily smokers (n = 24) and nonsmokers (n = 25).

RESULTS

Saliva NicAlert predicted self-reported smoking with 100% sensitivity and 96% specificity. At a cutoff of > 5 ppm, breath CO had 100% sensitivity and 100% specificity in predicting self-reported smoking. Breath CO was positively correlated with saliva NicAlert and negatively correlated with minutes since last cigarette.

CONCLUSION

Saliva NicAlert had high sensitivity and specificity in identifying daily smokers. Compared to saliva NicAlert, breath CO level was more indicative of recent smoking. Future treatment studies should evaluate the performance of saliva NicAlert as an alternative to the urine test.

Reliability and validity of a short form of the Marijuana Craving Questionnaire

BACKGROUND

The Marijuana Craving Questionnaire (MCQ) is a valid and reliable, 47-item self-report instrument that assesses marijuana craving along four dimensions: compulsivity, emotionality, expectancy, and purposefulness. For use in research and clinical settings, we constructed a 12-item version of the MCQ by selecting three items from each of the four factors that exhibited the greatest within-factor internal consistency (Cronbach's alpha coefficient).

METHODS

Adult marijuana users (n=490), who had made at least one serious attempt to quit marijuana use but were not seeking treatment, completed the MCQ-Short Form (MCQ-SF) in a single session.

RESULTS

Confirmatory factor analysis of the MCQ-SF indicated good fit with the 4-factor MCQ model, and the coefficient of congruence indicated moderate similarity in factor patterns and loadings between the MCQ and MCQ-SF. Homogeneity (unidimensionality and internal consistency) of MCQ-SF factors was also consistent with reliability values obtained in the initial validation of the MCQ.

CONCLUSIONS

Findings of psychometric fidelity indicate that the MCQ-SF is a reliable and valid measure of the same multidimensional aspects of marijuana craving as the MCQ in marijuana users not seeking treatment.

Age at menarche and weight concerns in relation to smoking trajectory and dependence among adolescent girls enrolled in a smoking cessation trial

Many girls adopt dieting and other practices (i.e. cigarette smoking) to control weight during puberty. This analysis explored the relationship between age at menarche and onset of daily smoking, and whether this relationship was influenced by weight concerns among treatment seeking female adolescents. The sample consisted of 71 participants enrolled in a smoking cessation trial (age 15.2+/-1.3 years; 74.7% European American, baseline BMI 24.7+/-5.4, age at menarche 11.7+/-1.3 years, Fagerström Test for Nicotine Dependence score 7.0+/-1.2). Over 60% of participants reported weight concerns at baseline, based on responses to the Eating Disorders module from the Diagnostic Interview for Children and Adolescents. Linear regression analyses revealed a significant association between age at menarche and age of onset of daily smoking (beta=0.18+/-0.09, p=0.038). Having weight concerns did not modify the relationships between age at menarche and smoking trajectory/severity or abstinence. Findings support previous research showing that early maturation represents a risk factor for substance use. Further study in larger samples that include non-treatment-seeking adolescent female smokers is warranted.

Reliability and validity of a Short Form of the Tobacco Craving Questionnaire

The Tobacco Craving Questionnaire (TCQ) is a valid and reliable 47-item self-report instrument that assesses tobacco craving in four dimensions: emotionality, expectancy, compulsivity, and purposefulness. For use in research and clinical settings, we constructed a 12-item version of the TCQ by selecting three items from each of the four factors that exhibited optimal within-factor reliability (Cronbach's alpha coefficient) and inter-item correlation. Smokers (N = 196) completed the TCQ-Short Form (TCQ-SF) after overnight tobacco deprivation and on a separate day during ad libitum smoking. Confirmatory factor analyses indicated acceptable model fit for a 4-factor model, with congruence coefficients suggesting high to very high similarity in factor patterns and magnitude of factor loadings between the TCQ and TCQ-SF in both conditions. Scores on each factor were significantly greater after tobacco deprivation than ad libitum smoking, were associated with measures of tobacco withdrawal, and varied with degree of nicotine dependence. Cronbach's alpha coefficients and average inter-item correlations were similar in both conditions and were consistent with reliability values obtained in the initial validation of the TCQ. Test-retest correlation coefficients were also similar to those found in a previous study. These findings suggest that the TCQ-SF is as valid and reliable as the 47-item TCQ in measuring tobacco craving.

Divided versus selective attention: evidence for common processing mechanisms

The current study revisited the question of whether there are brain mechanisms specific to divided attention that differ from those used in selective attention. Increased neuronal activity required to simultaneously process two stimulus dimensions as compared with each separate dimension has often been observed, but rarely has activity induced by a divided attention condition exceeded the sum of activity induced by the component tasks. Healthy participants performed a selective-divided attention paradigm while undergoing functional Magnetic Resonance Imaging (fMRI). The task required participants to make a same-different judgment about either one of two simultaneously presented stimulus dimensions, or about both dimensions. Performance accuracy was equated between tasks by dynamically adjusting the stimulus display time. Blood Oxygenation Level Dependent (BOLD) signal differences between tasks were identified by whole-brain voxel-wise comparisons and by region-specific analyses of all areas modulated by the divided attention task (DIV). No region displayed greater activation or deactivation by DIV than the sum of signal change by the two selective attention tasks. Instead, regional activity followed the tasks' processing demands as reflected by reaction time. Only a left cerebellar region displayed a correlation between participants' BOLD signal intensity and reaction time that was selective for DIV. The correlation was positive, reflecting slower responding with greater activation. Overall, the findings do not support the existence of functional brain activity specific to DIV. Increased activity appears to reflect additional processing demands by introducing a secondary task, but those demands do not appear to qualitatively differ from processes of selective attention.

Dose-related enhancement of mood and cognition in smokers administered nicotine nasal spray

The discovery of the role of nicotinic receptors in attention and memory has led to the testing of nicotinic analogs as cognitive enhancing agents in patient populations. Empirical information about nicotine's ability to enhance elements of attention and memory in normal individuals might guide development of therapeutic uses of nicotine in cognitively impaired populations. The purpose of this study was to determine the effect of nicotine on continuous attention, working memory, and computational processing in tobacco-deprived and nondeprived smokers. A total of 28 smokers (14 men, 14 women) participated in a double-blind, placebo-controlled, within-subject study, in which they were overnight (12 h) tobacco deprived at one session and smoked ad libitum before the other session. At each session, participants received 0, 1, and 2 mg nicotine via nasal spray in random order at 90 min intervals. Before and after each dose, a battery of cognitive, subjective, and physiological measures was administered, and blood samples were taken for plasma nicotine concentration. Overnight tobacco deprivation resulted in impaired functioning on all cognitive tests and increased self-reports of tobacco craving and negative mood; nicotine normalized these deficits. In the nondeprived condition, nicotine enhanced performance on the continuous performance test (CPT) and an arithmetic test in a dose-related manner, but had no effect on working memory. In general, women were more sensitive than men to the subjective effects of nicotine. These results provide an unequivocal determination that nicotine enhanced attentional and computational abilities in nondeprived smokers and suggest these cognitive domains as substrates for novel therapeutic indications.

Enhanced identification of smoking-related words during the attentional blink in smokers

The attentional blink (AB) occurs when ongoing processing of one target (T1) in a series of rapidly presented stimuli impairs processing of a subsequently presented second target (T2), such that T2 cannot be consciously perceived or reported. There is evidence that the AB can be influenced by the emotional or motivational salience of T2. We examined whether the AB could be attenuated by smoking-related stimuli in smokers. Heavy smokers (N=55) performed an AB task on two occasions, once following 12-h of abstinence and once following ad libitum smoking. T2s were either smoking-related or neutral (household-related) words, and lagged T1 by 0 to 7 distracter words. T1s were all neutral words. Each word was presented for 130 ms. Subjects were required to recall T1 and T2 immediately after each trial. There was a significant word type by lag interaction, whereby smoking-related T2s were recalled better than neutral T2s at early, but not late, lags. The word type effect at early lags was significantly associated with attentional bias assessed on the smoking Stroop task, but was not significantly moderated by abstinence. These data indicate that, in heavy smokers, smoking-related stimuli are more likely to engage conscious awareness than neutral words under conditions of limited attentional resources.

Associations between Cloninger's temperament dimensions and acute tobacco withdrawal

This study examined associations between three temperament dimensions measured by the Temperament and Character Inventory-125 [Cloninger, C.R. (1992). The Temperament and Character Inventory-125 (TCI-125; Version 1.)] and tobacco abstinence effects. Smokers (N=203, >/= 15 cigarettes/day) attended two laboratory sessions, one following 12 h of abstinence and the other following ad libitum smoking (order counterbalanced). Participants completed measures of withdrawal symptoms, cigarette urges, and affect. Smokers high in Novelty Seeking reported greater abstinence-induced increases in several nicotine withdrawal symptoms, negative affect, and cigarette craving. Smokers high in Harm Avoidance reported greater abstinence-induced increases in negative affect and urges to smoke to relieve distress. Reward Dependence was not associated with abstinence effects. Novelty Seeking and Harm Avoidance showed independent predictive associations with negative affect and urges, and their associations with abstinence effects persisted when controlling for FTND scores. Smokers with different temperaments display different patterns of acute tobacco withdrawal, and may benefit from treatments matched to their particular abstinence profile.

Single and multiple doses of rimonabant antagonize acute effects of smoked cannabis in male cannabis users

RATIONALE

A single 90-mg dose of the cannabinoid CB1 receptor antagonist rimonabant attenuates effects of smoked cannabis in humans.

OBJECTIVES

The objective of this study is to evaluate whether repeated daily 40-mg doses of rimonabant can attenuate effects of smoked cannabis to the same extent as a single higher (90 mg) dose.

MATERIALS AND METHODS

Forty-two male volunteers received one of three oral drug regimens in a randomized, double blind, parallel group design: (1) 40 mg rimonabant daily for 15 days, (2) placebo for 14 days, then 90 mg rimonabant on day 15, or (3) placebo for 15 days. All participants smoked an active or placebo cannabis cigarette 2 h after medication on days 8 and 15. Subjective effects were measured with visual analog scales and the marijuana-scale of the Addiction Research Center Inventory.

RESULTS

Cannabis-induced tachycardia was significantly lower for the 40-mg group on day 8 and for the 40 and 90 mg rimonabant groups on day 15 as compared to placebo. The 40-mg dose significantly decreased peak subjective effects on day 8. Neither the 90-mg nor 40-mg doses significantly decreased peak subjective effects on day 15. Rimonabant treatment did not significantly affect Delta(9)-tetrahydrocannabinnol pharmacokinetics.

CONCLUSIONS

Repeated lower daily rimonabant doses (40 mg) attenuated the acute physiological effects of smoked cannabis to a similar degree as a single 90-mg dose; repeated 40-mg doses attenuated subjective effects after 8 but not 15 days.

Consistency of subjective responses to imagery-induced tobacco craving over multiple sessions

Although studies have demonstrated the validity of imagery procedures to elicit tobacco craving responses in single sessions, few studies have examined the consistency of responding in the same individuals over multiple experimental sessions. In this study, nondeprived smokers were presented with a randomized series of imagery scripts that varied in the intensity of smoking-urge content. At each of five sessions spaced over several weeks, participants were exposed to six imagery trials (two each of no-, low-, and high-intensity imagery scripts). After each trial, participants completed subjective measures of tobacco craving and mood. Ratings of craving and negative mood significantly increased as a function of smoking-urge intensity, which was consistent across the five sessions. Further, significant intraclass correlations indicated that craving and mood responses were highly reliable over the five sessions, as well as across two, three, and four sessions. These results have practical implications for examining individual differences in sensitivity to smoking cues and for studies involving repeated measurement of elicited craving over time.

Tobacco craving predicts lapse to smoking among adolescent smokers in cessation treatment

Previous research indicates that tobacco craving predicts relapse to smoking among adult smokers attempting to quit. We hypothesized a similar relationship between craving and lapse (any smoking following a period of abstinence) among adolescent smokers during the treatment phase of a clinical trial. A visit was considered a lapse visit if the participant reported smoking or had a carbon monoxide level of 7 ppm or greater subsequent to an abstinent visit. A total of 34 participants (mean age = 14.9 years [SD = 1.3]; mean cigarettes/day = 18.0 [SD = 7.6]; mean Fagerström Test for Nicotine Dependence score = 6.8 [SD = 1.34]; 65% female), were included in the present analysis of 167 treatment visits. Logistic regression analyses showed a positive relationship between degree of craving, measured by the Questionnaire on Smoking Urges, and lapse during smoking cessation treatment (p = .013). Additionally, linear regression analyses demonstrated a strong positive association between cigarettes smoked per day and craving scores (p<.001). Taken together with other data, these findings suggest that degree of craving might influence tobacco abstinence for adolescent smokers. Thus monitoring and addressing craving appears useful to increase the success of adolescent smoking cessation.

Effect of tobacco deprivation on the attentional blink in rapid serial visual presentation

When two targets are imbedded in rapid serial visual presentation (RSVP), identification of the second target (T2) is impaired if it occurs within 500 ms of the first target (T1). This attentional blink (AB) is thought to involve interference of resources in processing T1 and T2. The deleterious effect of tobacco deprivation on attention has been documented, but no studies have examined the AB. Nonsmokers (n=30), 12-h tobacco-deprived smokers (n=30), and nondeprived smokers (n=30) were randomly assigned to perform the RSVP with one of three stimulus-duration conditions (96, 113, or 130 ms). Participants completed 48 RSVP trials. Each trial consisted of 16 individually presented words (T1, T2, and 14 distractors), and T2 lagged T1 at serial positions 1-8. Participants verbalized T1 and T2 in order immediately after each trial. Identification of T2 (for correct T1 trials) was impaired at early versus late lag positions, which was especially pronounced in the most difficult (96 ms) condition. There was no evidence for group differences on the AB; however, deprived smokers were worse identifying T1 in the 113-ms condition. These results suggest that the AB is influenced by stimulus duration, but not by 12 h of tobacco deprivation.

Heroin and cocaine craving and use during treatment: measurement validation and potential relationships

Although commonly assessed with unidimensional scales, craving has been suggested to be multifaceted and to have a complex relationship with drug use and relapse. This study assessed the consistency and predictive validity of unidimensional and multidimensional craving scales. At the beginning of a 12-week outpatient treatment trial, opiate users (n = 101) and cocaine users (n = 72) completed unidimensional visual analog scales (VASs) assessing "want," "need," and "craving" and multidimensional 14- and 45-item versions of the Cocaine Craving Questionnaire (CCQ) or Heroin Craving Questionnaire (HCQ). Spearman correlations between the VASs and the first-order factors from the 45-item CCQ/HCQ were .20-.40, suggesting that the two types of assessment were not redundant. Treatment dropout and in-treatment drug use were more frequently predicted by scores on the 14- or 45-item CCQ than by VAS ratings. Results suggest that the CCQ/HCQ and the 14-item CCQ provide information that unidimensional VASs do not.

Effect of tobacco craving cues on memory encoding and retrieval in smokers

Previous studies have shown that cue-elicited tobacco craving disrupted performance on cognitive tasks; however, no study has examined directly the effect of cue-elicited craving on memory encoding and retrieval. A distinction between encoding and retireval has been reported such that memory is more impaired when attention is divided at encoding than at retrieval. This study tested the hypothesis that active imagery of smoking situations would impair encoding processes, but have little effect on retrieval. Imagery scripts (cigarette craving and neutral content) were presented either before presentation of a word list (encoding trials) or before word recall (retrieval trials). A working memory task at encoding and free recall of words were assessed. Results indicated that active imagery disrupted working memory on encoding trials, but not on retrieval trials. There was a trend toward impaired working memory following craving scripts compared with neutral scripts. These data support the hypothesis that the cognitive underpinnings of encoding and retrieval processes are distinct.

Methods for clinical research involving cannabis administration

Better scientific understanding of cannabis effects and the development of treatments for cannabis dependence require clinical studies involving cannabis administration. Cannabis can be administered by smoking a plant-derived cigarette or by oral or intravenous administration of delta9-tetrahydrocannabinol (THC), the primary psychoactive chemical in cannabis. The smoked route is most commonly used outside the laboratory, but is subject to wide variation in absorbed dose. Oral synthetic THC is a legally marketed medication (dronabinol), also subject to wide pharmacokinetic variation, but offering a greater safety margin because of slower onset of action and lower potency. Intravenous THC offers precise investigator control of dose and timing. Acute adverse effects of cannabis administration include tachycardia, orthostatic hypotension, pulmonary irritation (if smoked), motor incoordination, cognitive impairment, anxiety, paranoia, and psychosis. Screening of research subjects should identify and exclude those with risk factors for such events, e.g., a history of significant cardiovascular, pulmonary, or psychiatric disorders. Monitoring of subjects during cannabis administration should include heart rate, blood pressure, and mental status. Subjects should not be discharged from research participation until reevaluation has shown that they have returned to baseline status.