Impact of CYP2A6 Activity on Nicotine Reinforcement and Cue-Reactivity in Daily Smokers

INTRODUCTION

Variation in CYP2A6, the primary enzyme responsible for nicotine metabolism, is associated with nicotine dependence, cigarette consumption, and abstinence outcomes in smokers. The impact of CYP2A6 activity on nicotine reinforcement and tobacco cue-reactivity, mechanisms that may contribute to these previous associations, has not been fully evaluated.

AIMS AND METHODS

CYP2A6 activity was indexed using 3 genetic approaches in 104 daily smokers completing forced-choice and cue-induced craving tasks assessing nicotine reinforcement and tobacco cue-reactivity, respectively. First, smokers were stratified by the presence or absence of reduced/loss-of-function CYP2A6 gene variants (normal vs. reduced metabolizers). As nicotine metabolite ratio (NMR) is a reliable biomarker of CYP2A6 activity, our second and third approaches used additional genetic variants identified in genome-wide association studies of NMR to create a weighted genetic risk score (wGRS) to stratify smokers (fast vs. slow metabolizers) and calculate a wGRS-derived NMR.

RESULTS

Controlling for race and sex, normal metabolizers (vs. reduced) selected a greater proportion of puffs from nicotine-containing cigarettes (vs. denicotinized) on the forced-choice task (p = .031). In confirmatory analyses, wGRS-based stratification (fast vs. slow metabolizers) produced similar findings. Additionally, wGRS-derived NMR, which correlated with actual NMR assessed in a subset of participants (n = 55), was positively associated with the proportion of puffs from nicotine-containing cigarettes controlling for race and sex (p = .015). None of the CYP2A6 indices were associated with tobacco cue-reactivity in minimally deprived smokers.

CONCLUSIONS

Findings suggest increased nicotine reinforcement is exhibited by smokers with high CYP2A6 activity, which may contribute to heavier smoking and poorer cessation outcomes previously reported in faster metabolizers.

IMPLICATIONS

CYP2A6 activity is a key determinant of smoking behavior and outcomes. Therefore, these findings support the targeting of CYP2A6 activity, either therapeutically or as a clinically relevant biomarker in a precision medicine approach, for tobacco use disorder treatment.

Significant association of nicotine reinforcement and cue reactivity: a translational study in humans and rats

Relapse is common amongst smokers attempting to quit and tobacco cue-induced craving is an important relapse mechanism. Preclinical studies commonly use cue-induced reinstatement of nicotine seeking to investigate relapse neurobiology. Previous research suggests dependence severity and nicotine intake history affect smoking resumption and cue-induced reinstatement of nicotine seeking. However, behavioural data may be interpreted in terms of nicotine reinforcement. This translational study investigated if individual differences in objectively assessed nicotine reinforcement strength were associated with cue-reactivity in both rats and human smokers, which to our knowledge has not been investigated before. Rats (n = 16) were trained to self-administer nicotine and were tested on a progressive ratio schedule of nicotine reinforcement, to assess reinforcer strength, and on a test of cue-induced reinstatement of nicotine seeking. Nicotine reinforcement strength was assessed in human smokers (n = 104) using a forced choice task (nicotine containing vs. denicotinised cigarettes) and self-reported cue-induced craving was assessed following exposure to smoking and neutral cues. Responding for nicotine under progressive ratio was strongly positively correlated with cue-induced reinstatement of nicotine seeking in rats. Nicotine choices in human smokers were significantly associated with cue-induced craving controlling for dependence severity, years of smoking, and urge to smoke following neutral cues. Findings suggest nicotine reinforcement strength is associated with both types of cue-induced behaviour, implying some translational commonality between cue-induced craving in human smokers and cue-induced reinstatement of nicotine seeking in rats. Findings are discussed in relation to clinical implications and whether these laboratory tasks assess drug 'wanting'.

The CB1R rs2023239 receptor gene variant significantly affects the reinforcing effects of nicotine, but not cue reactivity, in human smokers

INTRODUCTION

The cannabinoid CB1 receptor (CB1R) has been shown in preclinical studies to be involved in nicotine reinforcement and relapse-like behavior. The common single nucleotide polymorphism (SNP) rs2023239 may code for an alternative CB1R protein, alter CB1R expression, and be involved in nicotine dependence. To date, no study has explored the relationship between this SNP in CB1R and specific phenotypes of nicotine dependence.

METHODS

The current study investigated the influence of CB1R rs2023239 in nicotine reinforcement and craving in regular cigarette smokers. Current smokers (n = 104, cigarettes per day ≥ 10) were genetically grouped (C allele group vs. No C allele group) and underwent laboratory measures of nicotine reinforcement and smoking cue-elicited craving. Nicotine reinforcement was assessed using a forced choice paradigm, while a cue-reactivity procedure measured cue-elicited craving.

RESULTS

These results show that smokers with the C allele variant (CC + CT genotypes) experienced a lower nicotine reinforcement effect compared to those without the C allele (TT genotype). These results were similar in both our subjective and behavioral reinforcement measures, though the subjective effects did not withstand controlling for race. There was no difference between genotype groups with respect to cue-elicited craving, suggesting a lack of influence in cue reactivity.

CONCLUSION

Taken together, these results suggest that the variation in the CB1R (i.e., rs2023239 SNP) may play a larger role in nicotine reinforcement compared to cue reactivity. This work provides impetus to further understand the physiological mechanisms that explain how CB1Rs influence nicotine dependence phenotypes.

Exploring the role of the Ser9Gly (rs6280) Dopamine D3 receptor polymorphism in nicotine reinforcement and cue-elicited craving

Preclinical studies show that the dopamine D3 receptor (D3R) is involved in the reinstatement of drug seeking and motivation for drugs of abuse. A D3R gene variant, Ser9Gly (rs6280) has been linked to nicotine dependence, yet the mechanisms underlying its involvement in nicotine dependence is unclear. This study investigated the relationship between the Ser9Gly variant and measures of both nicotine reinforcement and cue-elicited craving. Phenotypes of smoking behaviors were assessed in genetically grouped (Glycine vs. No Glycine carriers) current smokers (n = 104, ≥ 10 cigarettes per day). Laboratory measures included a forced choice session (to measure reinforcement of nicotine containing vs. denicotinized cigarettes), and a cue-reactivity session (to measure smoking cues vs. neutral cues elicited craving). The forced choice procedure revealed that subjective ratings were significantly higher in response to nicotinized compared to denicotinized cigarettes; however the Ser9Gly variant did not influence this effect. By comparison, smoking cues elicited greater craving over time compared to neutral cues, and Glycine carriers of the Ser9Gly D3R variant seem to experience a significant blunted cue-elicited craving effect. Results support D3R involvement in nicotine cue reactivity. However, more research is needed to reveal how this gene variant modulates various aspects of nicotine dependence.

Nicotine Intake in Pregnant Smokers and a General Population of Smokers

OBJECTIVE

The purpose of this study was to assess whether pregnant smokers have the same nicotine intake from cigarettes as a general population of smokers and whether the known lower daily cigarette consumption among pregnant smokers is associated with higher nicotine intake among pregnant smokers.

METHOD

The study was a cross-sectional comparison of pregnant smokers and a general population of smokers in smoking cessation clinics. Participants were treatment-seeking pregnant (n = 476), nonpregnant female (n = 116), and male (n = 195) smokers who participated in two independent smoking cessation trials. Nicotine intake was measured as saliva cotinine/ cigarette/kg body weight ratio.

RESULTS

The mean saliva cotinine (μg/L)/ cigarette/kg body weight (0.21, SD = 0.15) of pregnant smokers was similar to that of nonpregnant female smokers (0.24, SD = 0.14) and higher than that of male smokers (0.18, SD = 0.12, p = .002) despite a substantially lower number of cigarettes per day (pregnant smokers: 12, SD = 6; nonpregnant female smokers: 26.6, SD = 11.7; male smokers: 23.5, SD = 9.5, p < .001). Among pregnant smokers, saliva cotinine, as expected, increased in parallel with the number of cigarettes per day, but nicotine intake (cotinine/cigarette/kg body weight) was inversely associated with daily cigarette consumption (p < .001). No association between cigarettes per day and nicotine intake was observed in male and nonpregnant female smokers (p = .43).

CONCLUSIONS

This secondary analysis showed that pregnant smokers' nicotine intake was similar to that of a general population of smokers despite a lower cigarette consumption rate. Among pregnant smokers, lower daily cigarette consumption was associated with higher nicotine intake from cigarettes, suggesting compensatory smoking.

Cigarette Smoking During Pregnancy: Do Complete Abstinence and Low Level Cigarette Smoking Have Similar Impact on Birth Weight?

OBJECTIVES

Despite awareness of negative health outcomes associated with smoking, pregnant smokers might reduce their tobacco consumption thinking that a low smoking rate reduces smoking-related negative birth outcomes. We aimed to assess in a clinical sample whether there is a smoking rate that would not impact on birth weight (BW).

METHODS

Pregnant smokers ≥18 years, gestational age of 9-20 weeks of amenorrhea, motivated to quit smoking, smoking ≥5 cigarettes/day (cpd) and their newborns (381 singleton, live births) were included in this secondary analysis of a French smoking cessation trial.

RESULTS

The mean BW when the mother quit smoking was 3417 g (95 % CI: 3098-3738 g); when smoking >0<5 cpd, 3081g (3003-3159 g); when smoking 5-9 cpd, 3043 g (2930-3157 g); and when smoking ≥10 cpd, 2831 g (2596-3157 g) (p = .006). The corresponding effect sizes ranged from medium to large (Cohen's d for BW: 0.54, 0.57 and 0.85) compared to BW when the mother quit. In the multivariable analysis, adjusted for all significant confounders, when the mother smoked on average >0<5 cpd, the loss in BW was 228 g; when smoking 5-9 cpd, 251 g; and when smoking ≥10 cpd, 262 g (all p ≤ .02) compared to newborns' BW of mothers who stopped smoking since quit date.

CONCLUSIONS

Even low cigarette consumption during pregnancy is associated with BW loss. All efforts should be made to help pregnant smokers quit completely during their pregnancy.

IMPLICATIONS

As an alternative to quitting smoking, pregnant smokers reduce their smoking rate thinking that this diminishes smoking-related negative health outcomes. No study has established whether low smoking rate (more than 0 but less than 5 cpd) during pregnancy impacts BW compared to abstinence from smoking. Among treatment-seeking pregnant smokers BW of newborns of mothers who smoked even less than 5 cpd was significantly lower than of those whose mothers quit; effect sizes of different consumption levels on BW ranged from moderate (>0<5 cpd) to large (≥10 cpd). Even low smoking rate is associated with reduced BW compared to complete maternal smoking abstinence.

Antipsychotic Treatment and Tobacco Craving in People With Schizophrenia

OBJECTIVE

Nicotine dependence is high in schizophrenia, and craving is known to impact relapse during quit attempts.

METHODS

We compared tobacco craving in smokers with schizophrenia treated with different antipsychotics.

RESULTS

Mean craving scores were lowest in participants receiving first-generation antipsychotics, although these differences were not statistically significant. Craving with clozapine was not lower than with other antipsychotics.

CONCLUSIONS

Further research is needed to determine whether differences in craving exist between antipsychotic classes.

Predictors of the Perception of Smoking Health Risks in Smokers With or Without Schizophrenia

OBJECTIVE

This study sought to examine the predictors of health risk perception in smokers with or without schizophrenia.

METHODS

The health risk subscale from the Smoking Consequences Questionnaire was dichotomized and used to measure health risk perception in smokers with (n = 67) and without schizophrenia (n = 100). A backward stepwise logistic regression was conducted using variables associated at the bivariate level to determine multivariate predictors.

RESULTS

Overall, 62.5% of smokers without schizophrenia and 40.3% of smokers with schizophrenia completely recognize the health risks of smoking (p ≤ .01). Multivariate predictors for smokers without schizophrenia included: sex (Exp (B) = .3; p < .05), Smoking Consequences Questionnaire state enhancement (Exp (B) = .69; p < .01), and craving relief (Exp (B) = 1.8; p < .01). Among smokers with schizophrenia, predictors were education (Exp (B) = .7; p < .05), nicotine dependence (Exp (B) = .5; p < .01), motivation to quit (Exp (B) = 1.8; p < .01), and Smoking Consequences Questionnaire craving relief (Exp (B) = 1.8; p < .01).

CONCLUSIONS

There was overlap and differences between predictors in smokers with and without schizophrenia. Commonly used techniques for education on the health consequences of cigarettes may work in smokers with schizophrenia, but intervention efforts specifically tailored to smokers with schizophrenia might be more efficacious.

Cross validation of the prognostic and diagnostic utility of tobacco craving in a general and a pregnant sample of treatment-seeking smokers

BACKGROUND

Valid and reliable brief measures of tobacco craving are necessary for research and clinical purposes. However, comparisons of the utility of single-item and brief multidimensional craving measures are scarce.

METHODS

We analyzed two tobacco craving measures, the French versions of the 12-item Tobacco Craving Questionnaire (FTCQ-12) and the single craving item on the Minnesota Nicotine Withdrawal Scale, in pregnant and non-pregnant (females and males) French smokers from two independent smoking cessation trials. Using data from pregnant smokers, we estimated first a prognostic model for each measure and compared their ability to predict relapse from one visit to the next. We next used cutoff values for both measures to determine how well craving distinguished current smokers from abstainers. For cross-validation, we tested how well the same cut-off values generalized to non-pregnant smokers.

RESULTS

Two FTCQ-12 factors (Expectancy and Purposefulness) predicted smoking status; scores were higher in pregnant non-abstainers than abstainers. The sum of these two factors, FTCQ-12 risk score (RS), yielded higher sensitivity both in prognostic and diagnostic models than single-item MNWS craving. FTCQ-12 RS had higher sensitivity among pregnant than non-pregnant smokers. Specificity of both tobacco craving measures was similar among pregnant smokers, but higher with MNWS craving than with FTCQ-12 RS in non-pregnant smokers.

CONCLUSIONS

FTCQ-12 RS and MNWS craving can be used together in clinical practice to rapidly predict smoking status. Interventions targeting Expectancy and Purposefulness may result in higher likelihood of abstinence, especially among pregnant smokers.

Black Cigarette Smokers Report More Attention to Smoking Cues Than White Smokers: Implications for Smoking Cessation

INTRODUCTION

Black cigarette smokers have lower rates of smoking cessation compared with Whites. However, the mechanisms underlying these differences are not clear. Many Blacks live in communities saturated by tobacco advertisements. These cue-rich environments may undermine cessation attempts by provoking smoking. Moreover, attentional bias to smoking cues (attention capture by smoking cues) has been linked to lower cessation outcomes. Cessation attempts among Blacks may be compromised by attentional bias to smoking cues and a cue-rich environment.

METHOD

Attention to smoking cues in Black and White smokers was examined in 2 studies. In both studies, assessments were completed during 2 laboratory visits: a nonabstinent session and an abstinent session. In study 1, nontreatment-seeking smokers (99 Whites, 104 Blacks) completed the Subjective Attentional Bias Questionnaire (SABQ; a self-report measure of attention to cues) and the Smoking Stroop task (a reaction time measure of attentional bias to smoking cues). In study 2, 110 White and 74 Black treatment-seeking smokers completed these assessments and attempted to quit.

RESULTS

In study 1, Blacks reported higher ratings than Whites on the SABQ (p = .005). In study 2, Blacks also reported higher ratings than Whites on the SABQ (p = .003). In study 2, Blacks had lower biochemical-verified point prevalence abstinence than Whites, and the between-race difference in outcome was partially mediated by SABQ ratings.

CONCLUSION

Blacks reported greater attention to smoking cues than Whites, possibly due to between-race differences in environments. Greater attention to smoking cues may undermine cessation attempts.

Validation of the French version of the marijuana craving questionnaire (MCQ) generates a two-factor model

BACKGROUND

Craving is a major issue in drug addiction, and a target for drug treatment. The Marijuana Craving Questionnaire-Short Form (MCQ-SF) is a useful tool for assessing cannabis craving in clinical and research settings.

OBJECTIVE

To validate the French version of the MCQ-SF (FMCQ-SF).

METHODS

Young adult cannabis users not seeking treatment (n = 679) completed the FMCQ-SF and questionnaires assessing their frequency of cannabis use and craving, cannabis use disorder criteria, and alcohol use.

RESULTS

Confirmatory factor analysis of the four-factor FMCQ-SF model did not fit the data well. Exploratory factor analysis suggested a two-factor solution ("pleasure", characterized by planning and expectation of positive effects, and "release of tension", characterized by relief from anxiety, nervousness, or tension) with good psychometric properties. This two-factor model showed good internal and convergent validity and correlated with cannabis abuse and dependence and with frequency of cannabis use and craving.

CONCLUSION

Validation of the FMCQ-SF generated a two-factor model, different from the four-factor solution generated in English language studies. Considering that craving plays an important role in withdrawal and relapse, this questionnaire should be useful for French-language addiction professionals.

A Comparison of the Fagerström Test for Cigarette Dependence and Cigarette Dependence Scale in a Treatment-Seeking Sample of Pregnant Smokers

INTRODUCTION

Valid and reliable brief measures of cigarette dependence are essential for research purposes and effective clinical care. Two widely-used brief measures of cigarette dependence are the six-item Fagerström Test for Cigarette Dependence (FTCD) and five-item Cigarette Dependence Scale (CDS-5). Their respective metric characteristics among pregnant smokers have not yet been studied.

METHODS

This was a secondary analysis of data of pregnant smokers (N = 476) enrolled in a smoking cessation study. We assessed internal consistency, reliability, and examined correlations between the instruments and smoking-related behaviors for construct validity. We evaluated predictive validity by testing how well the measures predict abstinence 2 weeks after quit date.

RESULTS

Cronbach's alpha coefficient for the CDS-5 was 0.62 and for the FTCD 0.55. Measures were strongly correlated with each other, although FTCD, but not CDS-5, was associated with saliva cotinine concentration. The FTCD, CDS-5, craving to smoke, and withdrawal symptoms failed to predict smoking status 2 weeks following the quit date.

CONCLUSIONS

Suboptimal reliability estimates and failure to predict short-term smoking call into question the value of including either of the brief measures in studies that aim to explain the obstacles to smoking cessation during pregnancy.

Subjective response to nicotine by menstrual phase

INTRODUCTION

The luteal menstrual phase might be a favorable time for smoking cessation when non-nicotine interventions (e.g. counseling, bupropion) are used, whereas the follicular menstrual phase appears favorable when nicotine interventions are used. Thus, there may be an interaction between menstrual phase and response to nicotine. We sought to examine the role of menstrual phase on response to nicotine during acute smoking abstinence.

METHODS

In this controlled cross-over trial, women completed two identical experimental sessions (follicular [F] vs. luteal [L] phase) after four days of biochemically-verified smoking abstinence. During the sessions, nicotine nasal spray was administered, and participants provided a series of subjective assessments.

RESULTS

Participants (n=140) were 29.7±6.6years old and smoked 12.6±5.8 cigarettes per day. Compared to the F phase, the L phase was associated with a greater increase in stimulation (7.2±2.2 vs. 14.4±2.3, p=0.01, respectively) and greater decrease in urge to smoke (-13.6±2.3 vs. -21.1±2.5, p=0.02, respectively) after the first dose of nicotine. No other significant differences were observed.

CONCLUSIONS

Out of 13 total measures examined at two different time points, we observed only two significant menstrual phase differences in the subjective response to nicotine. Therefore, these data do not provide strong evidence for a menstrual phase difference in the subjective response to nicotine. Additional research is needed to confirm this relationship and explore how non-nicotine smoking reinforcements (such as sensory sensations) may vary by menstrual phase.

Mu Opioid Receptor Binding Correlates with Nicotine Dependence and Reward in Smokers

The rewarding effects of nicotine are associated with activation of nicotine receptors. However, there is increasing evidence that the endogenous opioid system is involved in nicotine's rewarding effects. We employed PET imaging with [¹¹C]carfentanil to test the hypotheses that acute cigarette smoking increases release of endogenous opioids in the human brain and that smokers have an upregulation of mu opioid receptors (MORs) when compared to nonsmokers. We found no significant changes in binding potential (BP_ND) of [¹¹C]carfentanil between the placebo and the active cigarette sessions, nor did we observe differences in MOR binding between smokers and nonsmokers. Interestingly, we showed that in smokers MOR availability in bilateral superior temporal cortices during the placebo condition was negatively correlated with scores on the Fagerström Test for Nicotine Dependence (FTND). Also in smokers, smoking-induced decreases in [¹¹C]carfentanil binding in frontal cortical regions were associated with self-reports of cigarette liking and wanting. Although we did not show differences between smokers and nonsmokers, the negative correlation with FTND corroborates the role of MORs in superior temporal cortices in nicotine addiction and provides preliminary evidence of a role of endogenous opioid signaling in frontal cortex in nicotine reward.

Predicting smoking relapse with a multidimensional versus a single-item tobacco craving measure

BACKGROUND

Research suggests that craving is a predictor of smoking relapse. Craving can be assessed by multiple item or multifactorial scales or by single items. However, no systematic comparisons of their prognostic validity or accuracy have been published.

METHODS

The French versions of the 12-item Tobacco Craving Questionnaire (FTCQ-12) and the single craving item on the Minnesota Nicotine Withdrawal Scale (MNWS) are brief, valid, and reliable self-report measures of tobacco craving. In this secondary study, we analyzed data from French smokers with health-related problems enrolled in the Adjustment of DOses of NIcotine in Smoking (ADONIS) cessation trial. We estimated prediction models for each measure and compared their ability to distinguish correctly participants who relapsed from those who did not at 1-8 weeks after their quit date.

RESULTS

Adjusted for all potential confounders FTCQ-12 risk score (RS; Factor 2, Expectancy plus Factor 4, Purposefulness) and MNWS craving were valid predictors of smoking relapse at endpoints measured 1-7 weeks apart. Prognostic accuracy of FTCQ-12 RS was greatest at 1-2 weeks follow-up compared to only 1 week for MNWS craving. Sensitivity for FTCQ-12 RS and MNWS craving was 85% and 53%, respectively.

CONCLUSIONS

FTCQ-12 RS suggests a relapse process involving urges and desires in anticipation of the positive benefits of smoking linked with intent and planning to smoke. Findings also suggest that FTCQ-12 RS may be a better predictor instrument for smoking relapse than MNWS craving.

The acute tobacco withdrawal syndrome among black smokers

Black smokers have greater difficulty quitting tobacco than White smokers, but the mechanisms underlying between-race differences in smoking cessation are not clear. One possibility is that Black smokers experience greater acute withdrawal than Whites. We investigated whether Black (n = 104) and White smokers (n = 99) differed in abstinence-induced changes in self-report, physiological, and cognitive performance measures. Smokers not wishing to quit completed two counterbalanced experimental sessions. Before one session, they abstained from smoking for at least 12 hr. They smoked normally before the other session. Black smokers reported smaller abstinence-induced changes on a number of subjective measures including the total score of the 10-item Questionnaire for Smoking Urges (QSU) and the total score of the Wisconsin Smoking Withdrawal Scale (WSWS). However, on most subjective measures, and on all objective measures, there were no between-race differences in abstinence-induced change scores. Moreover, Black participants did not report lower QSU and WSWS ratings at the abstinent session, but they did experience significantly higher QSU and WSWS ratings at the nonabstinent session. Abstinence-induced changes in subjective, physiological, and cognitive measures in White smokers were similar for smokers of nonflavored and menthol-flavored cigarettes. There was no evidence that Black smokers experienced greater acute tobacco withdrawal than Whites. To the contrary, Black participants experienced smaller abstinence-induced changes in self-reported craving and withdrawal on some measures. Racial differences in smoking cessation are unlikely to be explained by acute withdrawal.

Dose-response effects of spectrum research cigarettes

INTRODUCTION

Experimental cigarettes are needed to conduct studies examining the effects of varying doses of nicotine content on smoking behavior. The National Institute on Drug Abuse contracted with Research Triangle Institute to make such cigarettes available to researchers. The goal of this study was to determine whether cigarettes that vary in nicotine content produce an expected dose-response effect.

METHOD

Two studies were conducted. The first study recruited subjects from 3 sites and consisted of a single, within-subject laboratory session. Subjects first smoked 4 puffs on their usual-brand cigarette and then in double-blind, random-order, smoked 4 puffs on each experimental cigarette that contained either low nicotine (LN, 0.4 mg/g), intermediate nicotine (IN, 5.7-5.8 mg/g), or high nicotine (HN, 11.4-12.8 mg/g). Each puffing bout was separated by a 30-min interval. Subjects completed questionnaires and were assessed for vital signs after each cigarette. The second study involved 1 site and used a between-subject design in which subjects were assigned to 1 of the 3 experimental cigarettes for 1 week. Subjective responses and biomarkers of exposure were assessed.

RESULTS

In the first study, significant dose-response effects were observed, particularly between the LN and HN cigarettes. The second study showed decreases in cigarette smoking and exposure biomarkers predominantly in the LN group, with no changes in the HN cigarette group.

CONCLUSIONS

These results are similar to those observed in prior literature, confirming that these experimental cigarettes can be used safely and with the expected pharmacological effects.

Illicit drug use in heavy smokers with and without schizophrenia

OBJECTIVE

The prevalence of cigarette smoking among people with schizophrenia is greater than that of the general population. Because smoking and use of other drugs covary, we examined illicit drug use in current smokers not trying to quit or reduce their tobacco use. We recruited outpatient participants who had a DSM-IV diagnosis of schizophrenia or schizoaffective disorder (schizophrenia, n=70) and a control group who had no Axis I psychiatric disorders (control, n=97). During a 2-3-hour session, participants completed demographic and research questionnaires, including the Drug Use Survey (DUS).

RESULTS

Participants with schizophrenia were older than controls (p<0.001) and smoked more cigarettes per day (p=0.01), but did not differ in degree of nicotine dependence. Ever using a drug was similar between the groups, except that significantly more participants with schizophrenia reported ever using hallucinogens (p<0.001) and inhalants (p=0.001). For alcohol, cocaine, and marijuana, fewer participants with schizophrenia were current users, but more participants with schizophrenia were past users (ps<0.0001). Heavy smokers from the general population continued to use illicit drugs throughout their lives, while schizophrenia participants had the highest period of illicit drug use in their 20s.

CONCLUSIONS

These data suggest that illicit drug use tends to be high in heavy cigarette smokers, regardless of a schizophrenia diagnosis. However, while illicit drug use is high across the lifespan of heavy smokers in the general population, heavy smokers with schizophrenia use illicit drugs mostly in the first decade of their illness.

Novel use of a lipid-lowering fibrate medication to prevent nicotine reward and relapse: preclinical findings

Experimental drugs that activate α-type peroxisome proliferator-activated receptors (PPARα) have recently been shown to reduce the rewarding effects of nicotine in animals, but these drugs have not been approved for human use. The fibrates are a class of PPARα-activating medications that are widely prescribed to improve lipid profiles and prevent cardiovascular disease, but these drugs have not been tested in animal models of nicotine reward. Here, we examine the effects of clofibrate, a representative of the fibrate class, on reward-related behavioral, electrophysiological, and neurochemical effects of nicotine in rats and squirrel monkeys. Clofibrate prevented the acquisition of nicotine-taking behavior in naive animals, substantially decreased nicotine taking in experienced animals, and counteracted the relapse-inducing effects of re-exposure to nicotine or nicotine-associated cues after a period of abstinence. In the central nervous system, clofibrate blocked nicotine's effects on neuronal firing in the ventral tegmental area and on dopamine release in the nucleus accumbens shell. All of these results suggest that fibrate medications might promote smoking cessation. The fact that fibrates are already approved for human use could expedite clinical trials and subsequent implementation of fibrates as a treatment for tobacco dependence, especially in smokers with abnormal lipid profiles.

Diagnostic criteria for cannabis withdrawal syndrome

OBJECTIVE

Cannabis withdrawal occurs in frequent users who quit, but there are no accepted diagnostic criteria for a cannabis withdrawal syndrome (CWS). This study evaluated diagnostic criteria for CWS proposed in DSM-V and two earlier proposals.

METHOD

A convenience sample of 384 adult, non-treatment-seeking lifetime cannabis smokers provided retrospective self-report data on their "most difficult" quit attempt without formal treatment, which was used in this secondary analysis. Prevalence, time of onset, and peak intensity (5-point Likert scale) for 39 withdrawal symptoms (drawn from the literature) were assessed via computer-administered questionnaire. Subject groups were compared using chi-square or ANOVA. Symptom clustering was evaluated with principal components analysis.

RESULTS

40.9% of subjects met the DSM-V criterion of ≥3 symptoms from a list of 7. There were no associations with sex, race, or type of cannabis preparation used. There were significant positive associations between duration or frequency of cannabis use prior to the quit attempt and experiencing CWS. Subjects with CWS had a significantly shorter duration of abstinence. Alternative syndromal criteria (dropping physical symptoms from DSM-V list; requiring ≥2 or ≥4 symptoms from a list of 11) yielded a similar prevalence of CWS and similar associations with prior cannabis use and relapse. The PCA yielded 12 factors, including some symptom clusters not included in DSM-V.

CONCLUSIONS

Findings support the concurrent and predictive validity of the proposed DSM-V CWS, but suggest that the list of withdrawal symptoms and number required for diagnosis warrant further evaluation.

Nicotine enhances alerting, but not executive, attention in smokers and nonsmokers

INTRODUCTION

Difficulty concentrating is a symptom of nicotine withdrawal that can contribute to relapse in individuals trying to quit smoking. The purpose of this study was to determine the effects of nicotine on executive and alerting attention in smokers and nonsmokers.

METHODS

Thirty daily smokers who were not tobacco deprived and 30 nonsmokers participated in the study. Participants received a single dose of intranasal nicotine (0, 0.5, or 1.5 mg) at each of 3 experimental sessions on separate days. Participants completed subjective ratings and 3 attention tasks before and after nicotine administration.

RESULTS

Nicotine had no effect on executive attention as assessed by a Rapid Serial Visual Presentation (RSVP) task or the Attention Network Test in smokers and nonsmokers. In contrast, nicotine enhanced alerting attention by decreasing errors on a Continuous Performance Test (CPT) in nonsmokers and improving the correct identification of target words on the RSVP task in smokers. Nonsmokers were more sensitive than smokers to the subjective, but not the cardiovascular, effects of nicotine.

CONCLUSIONS

The acute administration of intranasal nicotine improved alerting attention in nonsmokers as measured by the CPT, and in smokers as measured by the RSVP. Understanding the elements of attention enhanced by nicotine might guide the development of novel medications for tobacco dependence.

Perception of smoking risks and motivation to quit among nontreatment-seeking smokers with and without schizophrenia

OBJECTIVE

We examined perceived consequences/benefits of cigarette smoking and motivation for quitting in nontreatment-seeking smokers who had schizophrenia or schizoaffective disorder (N = 100) or had no Axis I psychiatric disorder (normals, N = 100).

METHODS

Participants completed questionnaires and provided a breath carbon monoxide (CO) sample 10-15 minutes after smoking 1 preferred-brand cigarette. Primary assessments included the Smoking Consequences Questionnaire-Adult, the Reasons for Quitting Scale, and the Stages of Change.

RESULTS

There were no differences between the schizophrenia and control group in mean age of smoking onset (16.2 ± 5.4 vs 15.6 ± 5.5 y, P = .44), number of cigarettes daily (17.9 ± 11.6 vs 17.0 ± 7.9, P = 0.51), or in breath CO (28.0 ± 14.5 vs 22.9 ± 8.0 ppm, P = .61). Compared with normals, people with schizophrenia report greater stimulation/state enhancement (P < .0001) and social facilitation (P < .004) from smoking. People with schizophrenia had less appreciation of health risks associated with smoking than normal controls (P < .0001) and were less motivated to quit smoking than normal controls (P = .002), even though they were as likely to be in the preparation stage of change. Immediate reinforcement (P = .04) and health concerns (P = .002) were rated lower as motivators for considering quitting smoking in schizophrenia than normals. People with schizophrenia reported greater motivation to stop smoking due to social pressure/rewards than normals (P = .047).

CONCLUSIONS

This study underscores the degree to which people with schizophrenia perceive the state-enhancing effects of smoking and their lower appreciation for health risks of smoking compared with normal controls.

Clonidine blocks stress-induced craving in cocaine users

RATIONALE

Reactivity to stressors and environmental cues, a putative cause of relapse in addiction, may be a useful target for relapse-prevention medication. In rodents, alpha-2 adrenergic agonists such as clonidine block stress-induced reinstatement of drug seeking, but not drug cue-induced reinstatement.

OBJECTIVE

The objective of this study is to test the effect of clonidine on stress- and cue-induced craving in human cocaine users.

METHODS

Healthy, non-treatment-seeking cocaine users (n = 59) were randomly assigned to three groups receiving clonidine 0, 0.1, or 0.2 mg orally under double-blind conditions. In a single test session, each participant received clonidine or placebo followed 3 h later by exposure to two pairs of standardized auditory-imagery scripts (neutral/stress and neutral/drug). Subjective measures of craving were collected.

RESULTS

Subjective responsivity ("crave cocaine" Visual Analog Scale) to stress scripts was significantly attenuated in the 0.1- and 0.2-mg clonidine groups; for drug-cue scripts, this attenuation occurred only in the 0.2-mg group. Other subjective measures of craving showed similar patterns of effects but Dose × Script interactions were not significant.

CONCLUSIONS

Clonidine was effective in reducing stress-induced (and, at a higher dose, cue-induced) craving in a pattern consistent with preclinical findings, although this was significant on only one of several measures. Our results, though modest and preliminary, converge with other evidence to suggest that alpha-2 adrenergic agonists may help prevent relapse in drug abusers experiencing stress or situations that remind them of drug use.

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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Affiliation(s)

Stephen J Heishman Nicotine Psychopharmacology Section, National Institute on Drug Abuse, NIH Intramural Research Program, 251 Bayview Blvd., Baltimore, MD 21224, USA.
Bethea A Kleykamp
Edward G Singleton

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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.