Reactivity to nicotine cues over repeated cue reactivity sessions

A randomized controlled experiment testing the use of virtual reality to trigger cigarette craving in people who smoke

Automated delivery of therapy in virtual reality (VR) has the potential to be used for smoking cessation. Most obviously, it could be used to practise and establish alternative reactions to smoking cues. The first step in treatment development is to show that VR environments can trigger sufficient cravings in smokers. We evaluated a new VR public house outdoor scenario with 100 individuals who smoked daily. Participants were randomly assigned to the VR scenario with smoking cues or a neutral experience in VR. The VR experiences were presented in a standalone VR headset. Before and after VR, we collected self-reported craving scores for cigarettes and alcohol using the Tobacco Craving Questionnaire (TCQ) and visual analogue scales (VAS). Physiological data were also collected. Compared to the neutral condition, exposure to the smoking cues led to a large increase in craving for a cigarette (TCQ β = 11.44, p < 0.0001, Cohen's d = 1.10) and also a moderate increase in craving for alcohol ( β = 0.7 , p = 0.017 , d = 0.50 ) . There were no significant physiological differences between the two conditions. These results provide good evidence that VR experiences can elicit strong craving for cigarettes. The programming can be part of developing a new VR cognitive therapy to help people reduce smoking.

Reduced executive and reward connectivity is associated with smoking cessation response to repetitive transcranial magnetic stimulation: A double-blind, randomized, sham-controlled trial

Repetitive transcranial magnetic stimulation (rTMS) can reduce cue-elicited craving, decrease cigarette consumption, and increase the abstinence rate in tobacco use disorders (TUDs). We used functional magnetic resonance imaging (fMRI) to investigate the effect of 10 sessions of rTMS on cortical activity and neural networks in treatment-seeking smokers. Smoking cue exposure fMRI scans were acquired before and after the 10 sessions of active or sham rTMS (10 Hz, 3000 pulses per session) to the left dorsal lateral prefrontal cortex (DLPFC) in 42 treatment-seeking smokers (≥ 10 cigarettes per day). Brain activity and functional connectivity were compared before and after 10 sessions of rTMS. Ten sessions of rTMS significantly reduced the number of cigarettes consumed per day (62.93%) compared to sham treatment (39.43%) at the end of treatment (p = 0.027). fMRI results showed that the rTMS treatment increased brain activity in the dorsal anterior cingulate cortex (dACC) and DLPFC, but decreased brain activity in the bilateral medial orbitofrontal cortex (mOFC). The lower strength of dACC and mOFC connectivity was associated with quitting smoking (Wald score = 5.00, p = 0.025). The reduction of cigarette consumption significantly correlated with the increased brain activation in the dACC (r = 0.76, p = 0.0001). By increasing the brain activity in the dACC and prefrontal cortex and decreasing brain activity in the mOFC, 10 sessions of rTMS significantly reduced cigarette consumption and increased quit rate. Reduced drive-reward and executive control functional connectivity was associated with the smoking cessation effect from rTMS. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT02401672.

Abstinence-Induced Nicotine Seeking Relays on a Persistent Hypoglutamatergic State within the Amygdalo-Striatal Neurocircuitry

Nicotine robustly sustains smoking behavior by acting as a primary reinforcer and by enhancing the incentive salience of the nicotine-associated stimuli. The motivational effects produced by environmental cues associated with nicotine delivery can progressively manifest during abstinence resulting in reinstatement of nicotine seeking. However, how the activity in reward neuronal circuits is transformed during abstinence-induced nicotine seeking is not yet fully understood. In here we used a contingent nicotine and saline control self-administration model to disentangle the contribution of cue-elicited seeking responding for nicotine after drug abstinence in male Wistar rats. Using ex vivo electrophysiological recordings and a network analysis approach, we defined temporal and brain-region specific amygdalo-striatal glutamatergic alterations that occur during nicotine abstinence. The results from this study provide critical evidence indicating a persistent hypoglutamatergic state within the amygdalo-striatal neurocircuitry over protracted nicotine abstinence. During abstinence-induced nicotine seeking, electrophysiological recordings showed progressive neuroadaptations in dorsal and ventral striatum already at 14-d abstinence while neuroadaptations in subregions of the amygdala emerged only after 28-d abstinence. The observed neuroadaptations pointed to a brain network involving the amygdala and the dorsolateral striatum (DLS) to be implied in cue-induced reinstatement of nicotine seeking. Together these data suggest long-lasting neuroadaptations that might reflect neuroplastic changes responsible to abstinence-induced nicotine craving. Neurophysiological transformations were detected within a time window that allows therapeutic intervention advancing clinical development of preventive strategies in nicotine addiction.

A methodological checklist for fMRI drug cue reactivity studies: development and expert consensus

Cue reactivity is one of the most frequently used paradigms in functional magnetic resonance imaging (fMRI) studies of substance use disorders (SUDs). Although there have been promising results elucidating the neurocognitive mechanisms of SUDs and SUD treatments, the interpretability and reproducibility of these studies is limited by incomplete reporting of participants' characteristics, task design, craving assessment, scanning preparation and analysis decisions in fMRI drug cue reactivity (FDCR) experiments. This hampers clinical translation, not least because systematic review and meta-analysis of published work are difficult. This consensus paper and Delphi study aims to outline the important methodological aspects of FDCR research, present structured recommendations for more comprehensive methods reporting and review the FDCR literature to assess the reporting of items that are deemed important. Forty-five FDCR scientists from around the world participated in this study. First, an initial checklist of items deemed important in FDCR studies was developed by several members of the Enhanced NeuroImaging Genetics through Meta-Analyses (ENIGMA) Addiction working group on the basis of a systematic review. Using a modified Delphi consensus method, all experts were asked to comment on, revise or add items to the initial checklist, and then to rate the importance of each item in subsequent rounds. The reporting status of the items in the final checklist was investigated in 108 recently published FDCR studies identified through a systematic review. By the final round, 38 items reached the consensus threshold and were classified under seven major categories: 'Participants' Characteristics', 'General fMRI Information', 'General Task Information', 'Cue Information', 'Craving Assessment Inside Scanner', 'Craving Assessment Outside Scanner' and 'Pre- and Post-Scanning Considerations'. The review of the 108 FDCR papers revealed significant gaps in the reporting of the items considered important by the experts. For instance, whereas items in the 'General fMRI Information' category were reported in 90.5% of the reviewed papers, items in the 'Pre- and Post-Scanning Considerations' category were reported by only 44.7% of reviewed FDCR studies. Considering the notable and sometimes unexpected gaps in the reporting of items deemed to be important by experts in any FDCR study, the protocols could benefit from the adoption of reporting standards. This checklist, a living document to be updated as the field and its methods advance, can help improve experimental design, reporting and the widespread understanding of the FDCR protocols. This checklist can also provide a sample for developing consensus statements for protocols in other areas of task-based fMRI.

Efectos de algunas señales visuales y olfativas sobre el consumo de cigarrillo y el ansia para fumar

Las señales inductoras para el consumo (SIC) son uno de los factores que inciden en que un fumador encienda, o no, el próximo cigarrillo. Las SIC impactan más a los fumadores no dependientes de la nicotina (FND) que a los fumadores dependientes (FD). Los FND no son dependientes de la nicotina y sus niveles de monóxido de carbono tienden a ser más bajos. Los FD muestran niveles de nicotina y monóxido de carbono más altos (dependientes). Este estudio evaluó el nivel de ansia de los individuos frente a imágenes relacionadas con el producto (cigarrillos y cajetilla de cigarrillos) y si existen diferencias entre inductores visuales y olfativos en relación con el consumo de cigarrillo. Los FD muestran niveles de nicotina y monóxido de carbono más altos. Los participantes mostraron mayor ansia ante las imágenes que presentaban cigarrillos saliendo de la cajetilla. No se hallaron diferencias entre inductores visuales y olfativos en relación con el consumo de cigarrillo. No obstante, la ocurrencia de fumar fue mayor en FD que en FND. Por eso, es importante clasificar el tipo de fumador en futuras investigaciones que pretendan evaluar esta población. 

A Meta-Analysis of Cue Reactivity in Tobacco Cigarette Smokers

INTRODUCTION

The cue reactivity paradigm allows for systematic evaluation of motivational responses to drug-related cues that may elicit drug use. The literature on this topic has grown substantially in recent decades, and the methodology used to study cue reactivity has varied widely across studies. The present research provided a meta-analytic investigation of variables that have an impact on cue reactivity effects to enhance our understanding of this key feature of tobacco use disorders.

METHODS

A total of 128 publications yielded 249 effect sizes, which were analyzed to investigate the magnitude of the cue reactivity effect and potential moderators.

RESULTS

Craving generated a moderate-to-large effect size (Hedges' g = 0.71, p < .001), indicating that drug cues produced significantly greater craving than neutral cues. However, physiological variables yielded significantly lower or nonsignificant effect sizes. Analyses of a variety of empirically and theoretically relevant moderator variables showed that cue modality, cue personalization, cue reactivity environment, and the use of multiple assessments of cue reactivity were significantly associated with the magnitude of cue-specific craving effects (ps < .001). Effect sizes were not significantly related to abstinence status, gender, cigarettes per day, and treatment-seeking status.

CONCLUSIONS

The results underscored the strength of self-reported craving as an index of cue reactivity across studies, which support theories that posit cue reactivity is core to the addictive process for daily tobacco cigarette smokers. The present research further elucidates the variables that alter the cue reactivity effects across studies and provides recommendations for future cue reactivity research.

IMPLICATIONS

A core feature of addiction is that drug-related cues can have a major impact on motivational responses across multiple substance use disorders, including tobacco cigarettes. This paper describes a meta-analysis updating and synthesizing cue reactivity research with tobacco cigarette smokers over the last 20 years, a time of rapid growth for this literature. The study leads to a better understanding of the cue reactivity paradigm across different self-report and physiological variables and identifies factors that may modulate addictive motivation for tobacco cigarettes.

Augmented Reality for Smoking Cessation: Development and Usability Study

Background

The recent widespread availability of augmented reality via smartphone offers an opportunity to translate cue exposure therapy for smoking cessation from the laboratory to the real world. Despite significant reductions in the smoking rates in the last decade, approximately 13.7% of the adults in the United States continue to smoke. Smoking-related cue exposure has demonstrated promise as an adjuvant therapy in the laboratory, but practical limitations have prevented its success in the real world. Augmented reality technology presents an innovative approach to overcome these limitations.

Objective

The aim of this study was to develop a smartphone app that presents smoking-related augmented reality images for cue exposure. Smokers provided feedback on the images and reported on the perceived urge to smoke, qualities of reality/coexistence, and general feedback about quality and functioning. The feedback was used to refine the augmented reality images within the app.

Methods

In collaboration with an augmented reality design company, we developed 6 smoking-related images (cigarette, lighter, ashtray, lit cigarette in ashtray, etc) and 6 neutral images similar in size or complexity for comparison (pen, eraser, notebook, soda bottle with droplets, etc). Ten smokers completed a survey of demographic characteristics, smoking history and behavior, dependence on nicotine, motivation to quit smoking, and familiarity with augmented reality technology. Then, participants viewed each augmented reality image and provided ratings on 10-point Likert scales for urge to smoke and reality/coexistence of the image into the scene. Participants were also queried with open-ended questions regarding the features of the images.

Results

Of the 10 participants, 5 (50%) had experienced augmented reality prior to the laboratory visit, but only 4 of those 5 participants used augmented reality at least weekly. Although the sample was small (N=10), smokers reported significantly higher urge to smoke after viewing the smoking-related augmented reality images (median 4.58, SD 3.49) versus the neutral images (median 1.42, SD 3.01) (Z=–2.14, P=.03; d=0.70). The average reality and coexistence ratings of the images did not differ between smoking-related and neutral images (all P>.29). Augmented reality images were found on average to be realistic (mean [SD] score 6.49 [3.11]) and have good environmental coexistence (mean [SD] score 6.93 [3.04]) and user coexistence (mean [SD] score 6.38 [3.27]) on the 10-point scale. Participant interviews revealed some areas of excellence (eg, details of the lit cigarette) and areas for improvement (eg, stability of images, lighting).

Conclusions

All images were generally perceived as being realistic and well-integrated into the environment. However, the smoking augmented reality images produced higher urge to smoke than the neutral augmented reality images. In total, our findings support the potential utility of augmented reality for cue exposure therapy. Future directions and next steps are discussed.

Differences in Magnitude of Cue Reactivity Across Durations of Smoking History: A Meta-analysis

BACKGROUND

Cue-elicited craving may vary due to duration of smoking history, increasing as more years of smoking strengthen associations between nicotine intake and cues. However, research on this relationship is virtually absent. This project assessed the relationship between cue reactivity and years of smoking.

METHODS

Data from 53 studies (68 effect sizes) were analyzed. Eligible studies were those measuring self-reported craving following cue exposure in nontreatment seeking smokers and reporting mean years smoking. Preliminary subgroup analyses identified methodological factors influencing cue-reactivity effect sizes; primary meta-regression analysis assessed differences across years smoking; exploratory analyses assessed potential for ceiling effects.

RESULTS

Effect sizes varied due to abstinence requirement and cue presentation modality, but not dependence severity. Unexpectedly, meta-regression analysis revealed a decline in effect sizes across years smoking. Exploratory analyses suggested declines may have been due to a ceiling effect in craving measurement for those with longer smoking histories-more experienced smokers reported higher levels of craving at baseline or following neutral cue exposure, but all reported similar levels of craving after smoking cue exposure.

CONCLUSIONS

Methodological factors and duration of smoking history influenced measurement of cue reactivity. Highlighted were important relationships between years smoking and magnitude of cue reactivity, depending on use of baseline or neutral cue comparisons. Further research is needed to assess differences in cue reactivity due to duration of smoking history using participant-level data, directly testing for ceiling effects. In addition, cue-reactivity studies are needed across young adults to assess onset of associations between nicotine intake and cues.

IMPLICATIONS

This meta-analysis project contributes to the cue-reactivity literature by reporting on the previously ignored relationship between duration of smoking history and magnitude of cue-elicited craving. Results suggest that declines in cue-reactivity effect sizes across years of smoking may have been due to study-level methodological factors, but not due to differences in sample-level dependence severity. Cue-reactivity effect sizes were stable across years of smoking in studies using a neutral cue comparison but declined sharply in studies when baseline assessment (typically coupled with an abstinence requirement) was used.

The clinical potential of augmented reality

Augmented reality (AR) is a rapidly emerging technology that superimposes digital objects onto real-world scenes as viewed in real time through a smartphone, tablet, or headset. Whereas AR has been adopted for retail, entertainment, and professional training, it also has potential as a novel, mobile, and efficacious treatment modality for psychological disorders. In particular, extinction-based therapies (e.g., anxiety, substance use disorders) could utilize AR to present stimuli in natural environments, enhancing generalizability beyond the clinic. The limited psychological literature on AR has focused on the treatment of simple phobias. Here, with the goal of bringing this technology to the attention of clinicians and researchers, we describe AR, contrast it with virtual reality, review the theoretical foundation for extinction-based therapies, provide examples for the treatment of substance use disorders, and identify theoretical, practical, and implementation-based research questions.

Reward sensitivity and electrodermal responses to actions and outcomes in a go/no-go task

Skin conductance response (SCR) is used in psychophysiological research to measure the reactions of the autonomic nervous system to reward and punishment. While there is consistent evidence that SCR increases to both aversive and appetitive stimuli, it remains unclear whether SCR simply represents a general index of arousal to motivationally significant outcomes or may also differentiate action or inhibition of action that lead to such outcomes. Furthermore, individual differences in trait sensitivity to reward and punishment can influence physiological arousal during approach and avoidance behaviors. Yet, their inter-relationships have not been examined. To address these gaps, we employed a reward go/no-go task with ⅔ go and ⅓ no-go trials and an individually titrated go response window. Correct go and no-go responses were rewarded while incorrect responses were penalized. We examined whether SCR varied with outcome (win vs. loss), action (go vs. no-go), and individual differences in reward sensitivity (SR) and sex. The results showed greater SCRs to loss vs. win, to go vs. no-go success, and to go success in positive correlation with SR. Further, SCR mediated the relationship between SR and go success rate. In sex differences, men exhibited greater SCR which was more predictive of go success rate relative to women. In contrast, SCR was more predictive of no-go success rate in women. Thus, SCR varies according to behavioral contingency, outcome, sex, and reward sensitivity. These findings add to the literature by characterizing the individual and behavioral factors that may influence physiological arousal in response to salient events.

A Preliminary Examination of Nicotine-Free Electronic Cigarette Use During Cessation From Combustible Cigarettes

Despite the availability of smoking cessation strategies, smoking cue-induced craving remains a relatively untreated relapse risk factor. Utilizing nicotine-free electronic cigarettes (e-cigarettes) to extinguish the motivational influence of smoking cues may be a viable approach to address cue reactivity. In this pilot study, 26 daily tobacco smokers used nicotine-free e-cigarettes while being maintained on daily transdermal sustained-release nicotine replacement therapy (NRT) to mitigate pharmacological withdrawal. Sensitivity to cue-induced craving, measured by the rise in craving after a visual cue exposure task, was assessed at a baseline visit after smoking as usual and again after 2 weeks of nicotine-free e-cigarette and NRT use. Participants' pattern and amount of tobacco cigarette smoking were evaluated on both visits and 1 month posttreatment. Cue-induced craving significantly decreased after the 2-week intervention, yet withdrawal scores increased during this time. One month after study completion, participants continued to report significantly lower overall cigarette craving and conventional tobacco cigarette use. Including the 34.8% that were totally abstinent, 65.2% reported smoking fewer than 10 cigarettes per week (compared to 87.2 per week at baseline for the entire group). A linear regression revealed that greater baseline cue-induced craving predicted better outcomes, whereas more withdrawal at the e-cigarette visit was related to more smoking at 1 month. This proof-of-concept pilot study suggests that the addition of ad libitum nicotine-free e-cigarettes to an existing strategy of transdermal NRT may attenuate cue-induced craving for tobacco smoking. A larger sample that is powered for detecting additional factors and longer-term outcomes is warranted.

A placebo-controlled randomized trial of D-cycloserine augmentation of cue exposure therapy for smoking cessation

Recent studies underscore the importance of studying d-cycloserine (DCS) augmentation under conditions of adequate cue exposure treatment (CET) and protection from reconditioning experiences. In this randomized trial, we evaluated the efficacy of DCS for augmenting CET for smoking cessation under these conditions. Sixty-two smokers attained at least 18 hours abstinence following 4 weeks of smoking cessation treatment and were randomly assigned to receive a single dose of DCS (n=30) or placebo (n=32) prior to each of two sessions of CET. Mechanistic outcomes were self-reported cravings and physiologic reactivity to smoking cues. The primary clinical outcome was 6-week, biochemically-verified, continuous tobacco abstinence. DCS, relative to placebo, augmentation of CET resulted in lower self-reported craving to smoking pictorial and in vivo cues (d = 0.8 to 1.21) in a relevant subsample of participants who were reactive to cues and free from smoking-related reconditioning experiences. Select craving outcomes were correlated with smoking abstinence, and DCS augmentation was associated with a trend toward a higher continuous abstinence rate (33% vs. 13% for placebo augmentation). DCS augmentation of CET can significantly reduce cue-induced craving, supporting the therapeutic potential of DCS augmentation when applied under appropriate conditions for adequate extinction learning.

Early onset cigarette smokers exhibit greater P300 reactivity to smoking-related stimuli and report greater craving

Adolescence is a period during which a number of critical neuromaturation processes occur and the vulnerability for developing nicotine dependence is extremely high. Thus, early-onset (EO; age < 16 years old), relative to late-onset (LO; age ≥ 16 years old), tobacco smoking may be uniquely deleterious for developmentally immature systems that regulate neural signaling reactivity. This study investigated how age of tobacco smoking onset affects neurophysiological measures of smoking cue reactivity and reported craving in adult smokers. EO smokers (EOS; n = 8; 4 females), LO smokers (LOS; n = 10; 5 females), and healthy non-smokers (HNS; n = 10; 5 females) participated in an event-related potential (ERP) cue reactivity study with tactile and image stimuli. Participants handled neutral objects during one interval and smoking-related objects during a second interval. After each interval, they viewed smoking-related, neutral, or arousing images using an oddball paradigm. P300 ERPs and craving for tobacco were recorded during each session. P300 amplitudes were significantly higher in central midline (Cz) channel to smoking, but not neutral or arousing, images after handling smoking objects. Specifically, Cz P300 smoking amplitudes were significantly greater in EOS, relative to LOS and HNS, and associated with greater craving at baseline. There were no other group differences in mood or craving. EOS exhibited greater P300 reactivity to smoking-related stimuli, relative to LOS, suggesting a more sensitized neural response. EO smoking during early neuromaturation may alter neurophysiological signaling involved in responding to smoking-related stimuli, which could impact the outcome of smoking cessation interventions.

Paradoxical olfactory function in combat veterans: The role of PTSD and odor factors

Stress- and trauma-related disorders, including posttraumatic stress disorder (PTSD), are characterized by an increased sensitivity to threat cues. Given that threat detection is a critical function of olfaction and that combat trauma is commonly associated with burning odors, we sought a better understanding of general olfactory function as well as response to specific trauma-related (i.e. burning) odors in combat-related PTSD. Trauma-exposed combat veterans with (N = 22) and without (N = 25) PTSD were assessed for general and specific odor sensitivities using a variety of tools. Both groups had similar general odor detection thresholds. However, the combat veterans with PTSD, compared to combat veterans with comparable trauma exposure, but without PTSD, had increased ratings of odor intensity, negative valence, and odor-triggered PTSD symptoms, along with a blunted heart rate in response to burning rubber odor. These findings are discussed within the context of healthy versus pathological changes in olfactory processing that occur over time after psychological trauma.

Intranasal oxytocin dampens cue-elicited cigarette craving in daily smokers: a pilot study

Despite moderate success with pharmacological and behavioral treatments, smoking relapse rates remain high, and many smokers report that smoking cues lead to relapse. Therefore, treatments that target cue reactivity are needed. One candidate for reducing craving is the neuropeptide oxytocin (OT). Here, we investigated the effects of intranasal OT on two types of craving for cigarettes: craving following overnight abstinence and craving elicited by smoking-related cues. In this within-subject, placebo-controlled pilot study, smokers (N=17) abstained from smoking for 12 h before attending two sessions randomized to intranasal OT or placebo (i.e. saline nasal spray). On each session, participants received two doses of OT (20 IU) or placebo at 1-h intervals, and rated craving before and after each dose. Spontaneous cigarette craving was assessed after the first spray, and cue-elicited craving was assessed following the second spray. OT did not reduce levels of spontaneous craving after the first spray, but significantly dampened cue-induced smoking craving. These results provide preliminary evidence that OT can reduce cue-induced smoking craving in smokers. These findings provide an important link between preclinical and clinical studies aimed at examining the effectiveness of OT as a novel treatment for drug craving.

Detection of Craving for Gaming in Adolescents with Internet Gaming Disorder Using Multimodal Biosignals

The increase in the number of adolescents with internet gaming disorder (IGD), a type of behavioral addiction is becoming an issue of public concern. Teaching adolescents to suppress their craving for gaming in daily life situations is one of the core strategies for treating IGD. Recent studies have demonstrated that computer-aided treatment methods, such as neurofeedback therapy, are effective in relieving the symptoms of a variety of addictions. When a computer-aided treatment strategy is applied to the treatment of IGD, detecting whether an individual is currently experiencing a craving for gaming is important. We aroused a craving for gaming in 57 adolescents with mild to severe IGD using numerous short video clips showing gameplay videos of three addictive games. At the same time, a variety of biosignals were recorded including photoplethysmogram, galvanic skin response, and electrooculogram measurements. After observing the changes in these biosignals during the craving state, we classified each individual participant's craving/non-craving states using a support vector machine. When video clips edited to arouse a craving for gaming were played, significant decreases in the standard deviation of the heart rate, the number of eye blinks, and saccadic eye movements were observed, along with a significant increase in the mean respiratory rate. Based on these results, we were able to classify whether an individual participant felt a craving for gaming with an average accuracy of 87.04%. This is the first study that has attempted to detect a craving for gaming in an individual with IGD using multimodal biosignal measurements. Moreover, this is the first that showed that an electrooculogram could provide useful biosignal markers for detecting a craving for gaming.

Transcranial magnetic stimulation of the dorsal lateral prefrontal cortex inhibits medial orbitofrontal activity in smokers

BACKGROUND AND OBJECTIVE

Several studies have shown that repetitive transcranial magnetic stimulation (rTMS), applied to the dorsolateral prefrontal cortex (DLPFC), can reduce cue-elicited craving in smokers. Currently, the mechanism of this effect is unknown. We used functional magnetic resonance imaging (fMRI) to explore the effect of a single treatment of rTMS on cortical and sub-cortical neural activity in non-treatment seeking nicotine-dependent participants.

METHODS

We conducted a randomized, counterbalanced, crossover trial in which participants attended two experimental visits separated by at least 1 week. On the first visit, participants received either active, or sham rTMS (10 Hz, 5 s-on, 10 s-off, 100% motor threshold, 3,000 pulses) over the left DLPFC, and on the second visit they received the opposite condition (active or sham). Cue craving fMRI scans were completed before and after each rTMS session.

RESULTS

A total of 11 non-treatment seeking nicotine-dependent cigarette smokers were enrolled in the study [six female, average age 39.7 ± 13.2, average cigarettes per day 17.3 ± 5.9]. Active rTMS decreased activity in the contralateral medial orbitofrontal cortex (mOFC) and ipsilateral nucleus accumbens (NAc) compared to sham rTMS.

CONCLUSIONS

This preliminary data suggests that one session of rTMS applied to the DLPFC decreases brain activity in the NAc and mOFC in smokers.

SCIENTIFIC SIGNIFICANCE

rTMS may exert its anti-craving effect by decreasing activity in the NAc and mOFC in smokers. Despite a small sample size, these findings warrant future rTMS/fMRI studies in addictions. (Am J Addict 2017;26:788-794).

Alcohol consumption as a predictor of reactivity to smoking and stress cues presented in the natural environment of smokers

BACKGROUND AND RATIONALE

The high prevalence of co-occurring alcohol and tobacco use underscores the importance of understanding the influence of alcohol consumption on risk factors for smoking and relapse. Alcohol has been shown to impact reactivity to smoking and stress-related cues, both of which are common antecedents to smoking and smoking relapse.

OBJECTIVE

The objective of the current study is to examine associations between alcohol use, cigarette craving, and stress reactivity following exposure to smoking and stress cues delivered in participants' daily lives.

METHODS

Using cue-reactivity ecological momentary assessment (CREMA), adult smokers (n = 138) reported cigarette craving, stress, and past hour alcohol use on a mobile device four times per day for 2 weeks, resulting in a range of 4493-5983 data points per analysis. Questions were followed by exposure to pictorial neutral, stressful, or smoking cues delivered via the mobile device. Craving and affect were re-assessed following cue exposure.

RESULTS

Results showed that recent (past hour) alcohol use was significantly associated with increases in the following: (a) tonic (non-cue-elicited) cigarette craving, (b) stress cue-elicited cigarette craving, and (c) stress cue-elicited stress reactivity, in the context of high-baseline stress. There was no significant association between alcohol use and smoking cue-elicited craving.

CONCLUSIONS

Alcohol use may increase risk for smoking and relapse to smoking by increasing cigarette craving and, in certain contexts, stress following stress cue exposure. Though alcohol is known for its anxiolytic properties, under some conditions, it may increase reactivity to stress cues.

Extinction of Conditioned Responses to Methamphetamine-Associated Stimuli in Healthy Humans

RATIONALE

Contextual stimuli present during drug experiences become associated with the drug through Pavlovian conditioning and are thought to sustain drug-seeking behavior. Thus, extinction of conditioned responses is an important target for treatment. To date, acquisition and extinction to drug-paired cues have been studied in animal models or drug-dependent individuals, but rarely in non-drug users.

OBJECTIVE

We have recently developed a procedure to study acquisition of conditioned responses after single doses of methamphetamine (MA) in healthy volunteers. Here, we examined extinction of these responses and their persistence after conditioning.

METHODS

Healthy adults (18-35 years; N = 20) received two pairings of audio-visual stimuli with MA (20 mg oral) or placebo. Responses to stimuli were assessed before and after conditioning, using three tasks: behavioral preference, attentional bias, and subjective "liking."

RESULTS

Subjects exhibited behavioral preference for the drug-paired stimuli at the first post-conditioning test, but this declined rapidly on subsequent extinction tests. They also exhibited a bias to initially look towards the drug-paired stimuli at the first post-test session, but not thereafter. Subjects who experienced more positive subjective drug effects during conditioning exhibited a smaller decline in preference during the extinction phase. Further, longer inter-session intervals during the extinction phase were associated with less extinction of the behavioral preference measure.

CONCLUSIONS

Conditioned responses after two pairings with MA extinguish quickly, and are influenced by both subjective drug effects and the extinction interval. Characterizing and refining this conditioning procedure will aid in understanding the acquisition and extinction processes of drug-related conditioned responses in humans.

Cue-induced craving to paraphernalia and drug images in opioid dependence

BACKGROUND AND OBJECTIVES

Stimuli that are repeatedly paired with substance use, such as drug paraphernalia, can themselves elicit drug craving. The aim of this study was to examine whether particular cue types elicit greater craving responses than others among individuals with opioid dependence.

METHODS

Participants seeking inpatient treatment for opioid dependence were recruited for a study of cue-induced craving. This sample (N = 50), included 25 primary heroin users, 20 primary prescription opioid users, and 5 users of heroin and prescription opioids equally. Participants completed a cue reactivity task, in which images of drug-related stimuli were presented on a computer screen, each followed by a question assessing state drug craving.

RESULTS

Overall, participants reported higher craving following paraphernalia stimuli relative to drug stimuli. However, this was moderated by opioid type; there was significantly higher craving in response to images of paraphernalia cues in the heroin group, and higher craving in response to drug cues in the prescription opioid group.

DISCUSSION AND CONCLUSIONS

These findings highlight potential differences in cue reactivity to opioid paraphernalia and drug cues, which appears to be moderated by drug type.

SCIENTIFIC SIGNIFICANCE

Cue-induced craving is an important factor in relapse. This study adds further to the literature on cue-induced craving in opioid dependence, suggesting that craving may vary based on both cue type and opioid type. Future studies designed to discriminate the impact of substance of abuse, route of administration, and cue type will help to further clarify cue-induced craving in this population.

Individualized real-time fMRI neurofeedback to attenuate craving in nicotine-dependent smokers

BACKGROUND

Cue-induced craving plays an important role in relapse, and the neural correlates of cue-induced craving have been elucidated using fMRI. This study examined the utility of real-time fMRI (rtfMRI) neurofeedback to strengthen self-regulation of craving-related neural activation and cue-reactivity in cigarette smokers.

METHODS

Nicotine-dependent smokers were randomized to rtfMRI neurofeedback or to a no-feedback control group. Participants completed 3 neuroimaging visits. Within each visit, an initial run during which smoking-related cues were used to provoke craving, an individualized craving-related region of interest (ROI) in the prefrontal cortex or anterior cingulate cortex was identified. In the rtfMRI group, activity from the ROI was fed back via a visual display during 3 subsequent runs while participants were instructed to reduce craving during cue exposure. The control group had an identical experience with no feedback provided.

RESULTS

Forty-four nicotine-dependent smokers were recruited to participate in our study; data from the 33 participants who completed a 1-week follow-up visit were included in the analysis. Subjective craving ratings and cue-induced brain activation were lower in the rtfMRI group than in the control group.

LIMITATIONS

As participants were not seeking treatment, clinical outcomes are lacking.

CONCLUSION

Nicotine-dependent smokers receiving rtfMRI feedback from an individualized ROI attenuated smoking cue-elicited neural activation and craving, relative to a control group. Further studies are needed in treatment-seeking smokers to determine if this intervention can translate into a clinically meaningful treatment modality.

Does laboratory cue reactivity correlate with real-world craving and smoking responses to cues?

BACKGROUND

Laboratory cue reactivity (CR) assessments are used to assess smokers' responses to cues. Likewise, EMA recording is used to characterize real-world response to cues. Understanding the relationship between CR and EMA responses addresses the ecological validity of CR.

METHODS

In 190 daily smokers not currently quitting, craving and smoking responses to cues were assessed in laboratory CR and by real-world EMA recording. Separate CR sessions involved 5 smoking-relevant cues (smoking, alcohol, negative affect, positive affect, smoking prohibitions), and a neutral cue. Subjects used EMA to monitor smoking situations for 3 weeks, completing parallel situational assessments (presence of others smoking, alcohol consumption, negative affect, positive affect, and smoking prohibitions, plus current craving) in smoking and non-smoking occasions (averaging 70 and 60 occasions each). Analyses correlated CR craving and smoking cue responses with EMA craving and smoking correlations with similar cues.

RESULTS

Although some cues did not show main effects on average craving or smoking, a wide range of individual differences in response to cues was apparent in both CR and EMA data, providing the necessary context to assess their relationship. Laboratory CR measures of cue response were not correlated with real-world cue responses assessed by EMA. The average correlation was 0.03; none exceeded 0.32. One of 40 correlations examined was significantly greater than 0.

CONCLUSIONS

Laboratory CR measures do not correlate with EMA-assessed craving or smoking in response to cues, suggesting that CR measures are not accurate predictors of how smokers react to relevant stimuli in the real world.

Response Time to Craving-Item Ratings as an Implicit Measure of Craving-Related Processes

Drug craving is typically measured through explicit ratings of craving levels. We examined response time to craving ratings as an implicit measure of craving processes in cigarette smokers. Response time and inter-item variability were investigated as potential indices of certainty in craving ratings. Cigarette smokers, categorized as tobacco dependent or nondependent, completed multiple cue-reactivity sessions with smoking and neutral cues. After each cue, craving level and response time was assessed. Significant inverted-U relationships emerged between craving level and both response time and inter-item variability across conditions, sessions, and groups. Faster response times and less inter-item variability emerged after neutral relative to smoking cues for nondependent smokers and after smoking relative to neutral cues for dependent smokers. Response time provided incremental validity beyond craving level in predicting dependence. Results support use of response time as an implicit measure of craving processes and further distinguish craving experiences between dependent and nondependent smokers.

Sex differences in smoking cue reactivity: craving, negative affect, and preference for immediate smoking

BACKGROUND AND OBJECTIVES

Female smokers have greater difficulty quitting, possibly due to increased reactivity to smoking-related cues. This study assessed sex differences in craving, affect, and preference for immediate smoking after cue exposure.

METHODS

Regular smokers (n = 60; 50% female) were exposed to smoking and neutral cues in separate, counterbalanced sessions. Outcomes included changes in craving and affect and preference for immediate smoking following cue exposure.

RESULTS

Findings indicated that women exhibited greater preference for immediate smoking (p = .004), and reported greater cue-induced increases in cigarette craving (p = .046) and negative affect (p = .025).

DISCUSSION AND CONCLUSIONS

These data suggest that women may have greater difficulty inhibiting smoking after cue exposure, possibly as a consequence of greater increases in craving and negative affect.

SCIENTIFIC SIGNIFICANCE AND FUTURE DIRECTIONS

Findings suggest a mechanism that may contribute to greater cessation failure among female smokers.

Withdrawal Symptoms and Nicotine Dependence Severity Predict Virtual Reality Craving in Cigarette-Deprived Smokers

INTRODUCTION

Virtual reality (VR) has been shown to be effective in eliciting responses to nicotine cues in cigarette smokers. The primary aim of this study was to investigate whether cigarette-deprived smokers would exhibit increased craving and changes in heart rate when viewing cigarette related cues as compared to non-smoking cues in a VR environment, and the secondary aim was to assess the extent to which self-assessed measures of withdrawal and dependence correlated with VR craving.

METHODS

Nicotine-dependent cigarette smokers were recruited for a 2 day study. On Day 1, participants smoked as usual and on Day 2 were deprived from smoking overnight. On both days, participants completed self-assessment questionnaires on withdrawal, craving, and nicotine-dependence. Participants completed a VR session during the cigarette deprivation condition only (Day 2). During this session, they were exposed to active smoking and placebo (non-smoking) cues.

RESULTS

The data show that self-reported levels of "craving" (p < .01) and "thinking about cigarettes" (p < .0001) were significantly greater after exposure to the active cues versus non-smoking cues. Significant increases in heart rate were found for 3 of 4 active cues when compared to non-smoking cues (p < .05). Finally, significant positive correlations were found between self-reported craving prior to the VR session and craving induced by active VR cues (p < .01).

CONCLUSIONS

In this report, active VR cues elicited craving during cigarette deprivation. This is the first study to demonstrate that self-reported craving, withdrawal symptoms, and nicotine dependence severity predict cue-induced craving in the VR setting.

Olfactory cue reactivity in nicotine-dependent adult smokers

Cue-elicited reactivity is a significant factor in relapse during smoking quit attempts. Previous research has focused primarily on visual smoking cues, with very limited research examining reactivity to olfactory triggers. Twenty-six adult non-treatment-seeking, nicotine-dependent smokers were exposed to 7 odorants during a cue-reactivity session measuring heart rate, skin conductance, and subjective craving. Cues included 2 cigarette odors (fresh tobacco and cigarette smoke), 2 odors previously identified as smoking-related (freshly mowed grass and coffee), 2 odors previously identified as unrelated to smoking (lavender and burned rubber), and 1 odorless control (propylene glycol). Pairwise comparisons demonstrated that subjective intensity of craving was significantly higher following exposure to the fresh tobacco odor compared with the odorless control (p < .01). A significant main effect for cue type on a physiological measure of arousal was also revealed, with a fresh tobacco odor-elicited significant increase in skin conductance level compared with the odorless control. However, no main effect of cue type on heart rate was found (p = .25). The results of the present study indicate that cigarette odor is an effective olfactory cue that heightens both subjective craving and increases skin conductance in smokers. Future research is needed to evaluate whether avoidance of these odors, or extinction of responses to them, can reduce relapse risk during smoking quit attempts.

Cue-induced smoking urges deplete cigarette smokers' self-control resources

BACKGROUND

Exposure to smoking-related cues leads to increased urge to smoke in regular cigarette smokers and resisting these urges requires considerable self-control.

PURPOSE

Adopting a resource depletion model, two studies tested the hypothesis that resisting smoking urges depletes self-control resources.

METHODS

Adopting a within-participants randomized cross-over design, participants (study 1, N = 19; study 2, N = 32) were exposed to smoking-related (study 1: smoking images; study 2: cigarette cue-exposure task) and neutral (study 1: neutral images; study 2: drinking-straw task) cues with presentation order randomized. After each cue set, participants completed self-control tasks (study 1: handgrip task; study 2: handgrip and Stroop tasks), performance on which constituted dependent measures of self-control.

RESULTS

Self-control task performance was significantly impaired when exposed to smoking-related cues compared to neutral cues. No significant presentation-order effects, or interaction effects between stimulus and presentation order, were found.

CONCLUSIONS

Findings corroborate our hypothesis that resisting smoking urges depletes cigarette smokers' self-control resources and suggests that self-control capacity is governed by a limited resource.

Decline in cue-provoked craving during cue exposure therapy for smoking cessation

INTRODUCTION

Based on the principles of Pavlovian learning and extinction, cue exposure therapy (CET) involves repeated exposure to substance-associated cues to extinguish conditioned cravings and reduce the likelihood of relapse. The efficacy of CET is predicated on successful extinction, yet the process of extinction in CET trials has rarely been demonstrated. This study explored the extinction process using a cue-reactivity paradigm in smokers undergoing multiple CET sessions as part of a comprehensive smoking cessation treatment.

METHODS

The sample comprised 76 moderately dependent, treatment-seeking smokers who completed at least 4 CET sessions and 6 counseling sessions. The CET and counseling sessions were scheduled twice weekly, and participants began using transdermal nicotine replacement therapy on their quit day, which occurred prior to initiation of CET. Each CET session consisted of presentation of 140 images on a computer screen, with self-reported craving as the primary measure of cue reactivity.

RESULTS

Mixed-model analyses revealed a progressive decline in cue-provoked craving both within and across 6 sessions of CET. Moderator analyses showed that the decline in craving was greatest among those who displayed initial cue reactivity.

CONCLUSIONS

These data are consistent with the premise that CET can produce extinction of laboratory-based cue-provoked smoking cravings and highlight important individual differences that may influence extinction. Implications for conducting cue exposure research and interventions are discussed.

The magnitude and reliability of cue-specific craving in nondependent smokers

BACKGROUND

Cue-reactivity is a robust phenomenon in regular cigarette smokers (Carter and Tiffany, 1999), but it has not been widely investigated in nondependent smokers. Further, most research on cue-specific craving assesses response to cues in a single experimental session. As such, investigations of cue-specific craving have primarily measured state-like but not trait-like responses to smoking stimuli.

METHODS

This study measured general and cue-specific craving in nondependent smokers and assessed the within-session and cross-session reliability of these two facets of craving. Participants (n=154) attended five laboratory sessions over the course of three months and completed multiple cue-reactivity trials (using smoking and neutral in vivo and photographic stimuli) during each study visit.

RESULTS

Results indicated that smoking cues elicited significantly stronger craving than neutral cues across study sessions, and that craving ratings following smoking cues decreased across subsequent sessions. Within-session and cross-session reliability was extremely high.

CONCLUSIONS

Overall, findings indicate that nondependent smokers experience reactivity to smoking cues, and that this response is quite reliable within and across sessions. Further, the magnitude of cue-specific craving was comparable to what has been observed in heavy, dependent smokers.

Smoker reactivity to cues: effects on craving and on smoking behavior

We assessed craving and smoking in response to smoking-relevant cues. Two hundred seven daily smokers viewed images related to 1 of 6 cue sets (cigarettes, positive and negative affect, alcohol, smoking prohibitions, and neutral cues) in separate sessions. Compared with neutral cues, cigarette cues significantly increased craving, and positive affect cues significantly decreased craving. When subjects were then allowed to smoke during continuing cue exposure, cues did not affect the likelihood of smoking or the amount smoked (number of cigarettes, number of puffs, puff time, or increased carbon monoxide). However, craving intensity predicted likelihood of smoking, latency to smoke, and amount smoked, with craving increases after cue exposure making significant independent contributions. Some craving effects were curvilinear, suggesting that they are subject to thresholds and might not be observed under some circumstances.

Gender differences in craving and cue reactivity to smoking and negative affect/stress cues

There is evidence that women may be less successful when attempting to quit smoking than men. One potential contributory cause of this gender difference is differential craving and stress reactivity to smoking- and negative affect/stress-related cues. The present human laboratory study investigated the effects of gender on reactivity to smoking and negative affect/stress cues by exposing nicotine dependent women (n = 37) and men (n = 53) smokers to two active cue types, each with an associated control cue: (1) in vivo smoking cues and in vivo neutral control cues, and (2) imagery-based negative affect/stress script and a neutral/relaxing control script. Both before and after each cue/script, participants provided subjective reports of smoking-related craving and affective reactions. Heart rate (HR) and skin conductance (SC) responses were also measured. Results indicated that participants reported greater craving and SC in response to smoking versus neutral cues and greater subjective stress in response to the negative affect/stress versus neutral/relaxing script. With respect to gender differences, women evidenced greater craving, stress and arousal ratings and lower valence ratings (greater negative emotion) in response to the negative affect/stressful script. While there were no gender differences in responses to smoking cues, women trended towards higher arousal ratings. Implications of the findings for treatment and tobacco-related morbidity and mortality are discussed.

Does alexithymia explain variation in cue-elicited craving reported by methamphetamine-dependent individuals?

Drug craving is an important motivational phenomenon among addicted individuals, and successful management of craving is essential to both the initiation and maintenance of abstinence. Although craving in response to drug cues is common in drug-dependent individuals, it is not universal. At the present time, it is not known why approximately 20-30% of all addicted persons fail to report appreciable craving in laboratory-based cue reactivity studies. This study examined the possibility that alexithymia, a personality attribute characterized by a difficulty identifying and describing emotions, may contribute to the impoverished cue-elicited craving experienced by some addicts. Specifically, we tested the hypothesis that alexithymia, as measured by the Toronto Alexithymia Scale (TAS), would be inversely related to the magnitude of cue-elicited craving obtained in a cue reactivity protocol. Forty methamphetamine-dependent individuals completed the TAS and provided craving ratings for methamphetamine after presentation of methamphetamine-associated cues. Thirteen participants (32%) reported no methamphetamine cue-elicited craving. Contrary to expectation, TAS factor 1 (a measure of difficulty identifying feelings) scores were positively associated with cue-elicited craving. Thus, the results suggest that increasing difficulty-identifying feelings may be associated with higher cue-elicited craving. Clinical implications for this finding are discussed.

Validation of smoking-related virtual environments for cue exposure therapy

Craving is considered one of the main factors responsible for relapse after smoking cessation. Cue exposure therapy (CET) consists of controlled and repeated exposure to drug-related stimuli in order to extinguish associated responses. The main objective of this study was to assess the validity of 7 virtual reality environments for producing craving in smokers that can be used within the CET paradigm. Forty-six smokers and 44 never-smokers were exposed to 7 complex virtual environments with smoking-related cues that reproduce typical situations in which people smoke, and to a neutral virtual environment without smoking cues. Self-reported subjective craving and psychophysiological measures were recorded during the exposure. All virtual environments with smoking-related cues were able to generate subjective craving in smokers, while no increase was observed for the neutral environment. The most sensitive psychophysiological variable to craving increases was heart rate. The findings provide evidence of the utility of virtual reality for simulating real situations capable of eliciting craving. We also discuss how CET for smoking cessation can be improved through these virtual tools.

Cue-induced craving and physiological reactions in recently and long-abstinent heroin-dependent patients

OBJECTIVE

To understand the different patterns of cue-induced craving and physiological reactions among recently abstinent and long-abstinent heroin-dependent patients.

METHOD

26 healthy adult controls (HC), 29 long-abstinent (more than 1 year, LA), and 26 recently abstinent (less than 1 month, RA) heroin-dependent individuals were exposed to heroin-related and neutral video cues, one video per session, on different days in random order. Self-reported heroin craving by a 10-point visual analog scale (VAS), physiological reactions [skin conductance (SC), muscle electromyography (MEG), skin temperature (TEMP)] and cardiovascular arousal [heart rates (HR), systolic blood pressure (HBP) and diastolic blood pressure (LBP)] were assessed at baseline and after exposure.

RESULTS

Both heroin-abstinent groups showed increased heroin craving, SC, MEG, HR, SBP and LBP after exposure to heroin-related video, compared to the control group and compared to exposure to the neutral video. Except the RA group showed more HR changes, changes of heroin craving, SC, MEG, HR, SBP and LBP after exposure to the heroin cue video were not different between the LA and RA groups.

CONCLUSIONS

Abstinent heroin-dependent patients had elevated craving and physiological reactions after exposure to videos containing heroin-related cues and the cue induced responses still occurred in long-abstinent patients. This phenomenon should be addressed in treatment and recovery services for heroin dependence.

Feasibility of Using Virtual Reality to Assess Nicotine Cue Reactivity During Treatment

Cue reactivity assessments have been widely used to assess craving and attention to cues among cigarette smokers. Cue reactivity has the potential to offer insights into treatment decisions; however, the use of cue reactivity in treatment studies has been limited. This study assessed the feasibility of using a virtual reality-based cue reactivity assessment approach (VR-NCRAS) during treatment. In a clinical smoking cessation treatment study, 46 treatment-seeking nicotine-dependent adult smokers were assessed for cue reactivity at baseline, Week 4, and Week 10 of treatment. Measures of cue reactivity included subjective craving and attention to cues after exposure to two neutral and two smoking cue environments. Overall, feasibility of using VR-NCRAS was demonstrated and these findings support the use of the cue reactivity assessment during treatment, which can inform treatment decisions.

The clinical significance of drug craving

Although drug craving has received considerable research attention over the past several decades, to date there has been no systematic review of the general clinical significance of craving. This paper presents an overview of measurement issues of particular relevance to a consideration of use of craving in clinical settings. The paper then considers the relevance of craving across a broad array of clinical domains, including diagnosis, prognostic utility, craving as an outcome measure, and the potential value of craving as a direct target of intervention. The paper is both descriptive and prescriptive, informed by the current state of the science on craving with recommendations for the definition of craving, assessment practices, future research, and clinical applications. We conclude that craving has considerable utility for diagnosis and as a clinical outcome, and that findings from future research will likely expand the clinical potential of the craving construct in the domains of prognosis and craving as a treatment target.

Smoking cue reactivity across massed extinction trials: negative affect and gender effects

Designing and implementing cue exposure procedures to treat nicotine dependence remains a challenge. This study tested the hypothesis that gender and negative affect (NA) influence changes in smoking urge over time using data from a pilot project testing the feasibility of massed extinction procedures. Forty-three smokers and ex-smokers completed the behavioral laboratory procedures. All participants were over 17 years old, smoked at least 10 cigarettes daily over the last year (or the year prior to quitting) and had expired CO below 10 ppm at the beginning of the ~4-hour session. After informed consent, participants completed 45 min of baseline assessments, and then completed a series of 12 identical, 5-minute exposure trials with inter-trial breaks. Smoking cues included visual, tactile, and olfactory cues with a lit cigarette, in addition to smoking-related motor behaviors without smoking. After each trial, participants reported urge and negative affect (NA). Logistic growth curve models supported the hypothesis that across trials, participants would demonstrate an initial linear increase followed by a decrease in smoking urge (quadratic effect). Data supported hypothesized gender, NA, and gender×NA effects. Significant linear increases in urge were observed among high and low NA males, but not among females in either NA subgroup. A differential quadratic effect showed a significant decrease in urge for the low NA subgroup, but a non-significant decrease in urge in the high NA group. This is the first study to demonstrate gender differences and the effects of NA on the extinction process using a smoking cue exposure paradigm. Results could guide future cue reactivity research and exposure interventions for nicotine dependence.

Reactivity to in vivo marijuana cues among cannabis-dependent adolescents

INTRODUCTION

Cannabis dependence is a common but poorly understood condition in adolescents. Marijuana craving has been posited as a potential contributing factor to continued use and relapse, but relatively few studies have focused on the measurement of craving and reactivity to marijuana cues. The present work sought to explore reactivity to marijuana cues within this age group.

METHODS

Thirty treatment-seeking cannabis-dependent adolescents (age 13-20) completed a cue reactivity session, consisting of exposure to and manipulation of in vivo marijuana cues ("joint" and lighter) and matching neutral cues (pencil and eraser), in counterbalanced order. Subjective craving and physiological reactivity were assessed.

RESULTS

Participants demonstrated increased craving and skin conductance reactivity in response to marijuana cues, relative to neutral cues.

CONCLUSION

In vivo marijuana cues appear to elicit significant subjective and physiological reactivity among treatment-seeking cannabis-dependent adolescents. Further work is needed with a larger sample and with a wider variety of cues.

Counterbalancing in smoking cue research: a critical analysis

INTRODUCTION

Cue exposure research has been used to examine key issues in smoking research, such as predicting relapse, testing new medications, investigating the neurobiology of nicotine dependence, and examining reactivity among smokers with comorbid psychopathologies. Determining the order that cues are presented is one of the most critical steps in the design of these investigations. It is widely assumed that cue exposure studies should counterbalance the order in which smoking and control (neutral) cues are presented. This article examines the premises underlying the use of counterbalancing in experimental research, and it evaluates the degree to which counterbalancing is appropriate in smoking cue exposure studies.

METHODS

We reviewed the available literature on the use of counterbalancing techniques in human smoking cue exposure research.

RESULTS

Many studies counterbalancing order of cues have not provided critical analyses to determine whether this approach was appropriate. Studies that have reported relevant data, however, suggest that order of cue presentation interacts with type of cue (smoking vs. control), which raises concerns about the utility of counterbalancing. Primarily, this concern arises from potential carryover effects, in which exposure to smoking cues affects subsequent responding to neutral cues.

CONCLUSIONS

Cue type by order of cue interactions may compromise the utility of counterbalancing. Unfortunately, there is no obvious alternative that is optimal across studies. Strengths and limitations of several alternative designs are considered, and key questions are identified to advance understanding of the optimal conditions for conducting smoking cue exposure studies.

Evidence for greater cue reactivity among low-dependent vs. high-dependent smokers

INTRODUCTION

Cue reactivity paradigms are well-established laboratory procedures used to examine subjective craving in response to substance-related cues. For smokers, the relationship between nicotine dependence and cue reactivity has not been clearly established. The main aim of the present study was to further examine this relationship.

METHODS

Participants (N=90) were between the ages 18-40 and smoked > or =10 cigarettes per day. Average nicotine dependence (Fagerström Test for Nicotine Dependence; FTND) at baseline was 4.9 (SD=2.1). Participants completed four cue reactivity sessions consisting of two in vivo cues (smoking and neutral) and two affective imagery cues (stressful and relaxed), all counterbalanced. Craving in response to cues was assessed following each cue exposure using the Questionnaire of Smoking Urges-Brief (QSU-B). Differential cue reactivity was operationally defined as the difference in QSU scores between the smoking and neutral cues, and between the stressful and relaxed cues.

RESULTS

Nicotine dependence was significantly and negatively associated with differential cue reactivity scores in regard to hedonic craving (QSU factor 1) for both in vivo and imagery cues, such that those who had low FTND scores demonstrated greater differential cue reactivity than those with higher FTND scores (beta=-.082; p=.037; beta=-.101; p=.023, respectively). Similar trends were found for the Total QSU and for negative reinforcement craving (QSU factor 2), but did not reach statistical significance.

DISCUSSION

Under partially sated conditions, less dependent smokers may be more differentially cue reactive to smoking cues as compared to heavily dependent smokers. These findings offer methodological and interpretative implications for cue reactivity studies.

Identifying specific cues and contexts related to smoking craving for the development of effective virtual environments

Craving is considered the main variable associated with relapse after smoking cessation. Cue Exposure Therapy (CET) consists of controlled and repeated exposure to drug-related cues with the aim of extinguishing craving responses. Some virtual reality (VR) environments, such as virtual bars or parties, have previously shown their efficacy as tools for eliciting smoking craving. However, in order to adapt this technology to smoking cessation interventions, there is a need for more diverse environments that enhance the probability of generalization of extinction in real life. The main objective of this study was to identify frequent situations that produce smoking craving, as well as detecting specific craving cues in those contexts. Participants were 154 smokers who responded to an ad hoc self-administered inventory for assessing craving level in 12 different situations. Results showed that having a drink in a bar/pub at night, after having lunch/dinner in a restaurant and having a coffee in a cafe or after lunch/dinner at home were reported as the most craving-inducing scenarios. Some differences were found with regard to participants' gender, age, and number of cigarettes smoked per day. Females, younger people, and heavier smokers reported higher levels of craving in most situations. In general, the most widely cited specific cues across the contexts were people smoking, having a coffee, being with friends, and having finished eating. These results are discussed with a view to their consideration in the design of valid and reliable VR environments that could be used in the treatment of nicotine addicts who wish to give up smoking.

Effects of dopamine antagonists on drug cue-induced reinstatement of nicotine-seeking behavior in rats

Dopaminergic neurotransmission has been implicated in associative learning processes related to drugs of abuse. However, it is not clear whether blockade of activation of dopamine receptors alters conditioned incentive properties of nicotine-associated cues. Using a response-reinstatement procedure, this study examined the effects of antagonists selective for the D1 and the D2 subtypes of dopamine receptors on cue-induced reinstatement of nicotine-seeking behavior. Male Sprague-Dawley rats were trained in 30 daily 1 h sessions to intravenously self-administer nicotine (0.03 mg/kg/infusion) on a fixed ratio 5 schedule and associate a conditioned stimulus (cue) with each nicotine delivery. After extinction of responding by withholding nicotine (saline substitution) and its cue, the reinstatement tests were conducted following subcutaneous administration of a D1 antagonist SCH23390 (0, 5, 10, 30 microg/kg) or a D2 antagonist eticlopride (0, 5, 10, 30 microg/kg) in different groups of animals. Both SCH23390 and eticlopride significantly attenuated the magnitude of cue-elicited reinstatement of nicotine-seeking responding. These results indicate that activation of dopaminergic D1 and D2 receptors may play a role in mediating the conditioned motivational effects of nicotine-associated cues as measured in the response-reinstatement procedure. These findings suggest that manipulation of dopaminergic neurotransmission at D1 and/or D2 receptors may prove to be a potential target for the development of pharmacotherapy for prevention of environmental nicotine cue-triggered smoking relapse.

Extinction of drug cue reactivity in methamphetamine-dependent individuals

Conditioned responses to drug-related environmental cues (such as craving) play a critical role in relapse to drug use. Animal models demonstrate that repeated exposure to drug-associated cues in the absence of drug administration leads to the extinction of conditioned responses, but the few existing clinical trials focused on extinction of conditioned responses to drug-related cues in drug-dependent individuals show equivocal results. The current study examined drug-related cue reactivity and response extinction in a laboratory setting in methamphetamine-dependent individuals. Methamphetamine cue-elicited craving was extinguished during two sessions of repeated (3) within-session exposures to multi-modal (picture, video, and in-vivo) cues, with no evidence of spontaneous recovery between sessions. A trend was noted for a greater attenuation of response in participants with longer (4-7 day) inter-session intervals. These results indicate that extinction of drug cue conditioned responding occurs in methamphetamine-dependent individuals, offering promise for the development of extinction- based treatment strategies.

Menstrual cycle and cue reactivity in women smokers

INTRODUCTION

Emerging research suggests potential effects of the menstrual cycle on various aspects of smoking behavior in women, but results to date have been mixed. The present study sought to explore the influence of menstrual cycle phase on reactivity to smoking in vivo and stressful imagery cues in a sample of non-treatment-seeking women smokers.

METHODS

Via a within-subjects design, nicotine-dependent women (N = 37) participated in a series of four cue reactivity sessions, each during a distinct biologically verified phase of the menstrual cycle (early follicular [EF], mid-follicular [MF], mid-luteal [ML], and late luteal [LL]). Subjective (Questionnaire of Smoking Urges-Brief; QSU-B) and physiological (skin conductance and heart rate) measures of craving and reactivity were collected and compared across phases.

RESULTS

Subjective reactive craving (QSU-B) to smoking in vivo cues varied significantly across the menstrual cycle (p = .02) and was higher in both EF and MF phases versus ML and LL phases, but this finding was not sustained when controlling for reactivity to neutral cues. Heart rate reactivity to stressful imagery cues (p = .01) and skin conductance reactivity to smoking in vivo cues (p = .05) varied significantly across the menstrual cycle upon controlling for reactivity to neutral cues, with highest reactivity during the MF phase.

DISCUSSION

Menstrual cycle phase may have an effect on reactivity to smoking-related and stressful cues among women smokers. These findings contribute to an expanding literature, suggesting menstrual cycle effects on smoking behaviors in women.

Peer pressure, psychological distress and the urge to smoke

Background:

Psychology and addiction research have found that cigarette smokers react with subjective and automatic responses to stimuli associated with smoking. This study examines the association between the number of cigarettes smokers consume per month and their response to cues derived from peer and psychological distress.

Methods:

We studied 1,220 adult past and current smokers drawn from a national face-to-face interview survey administered in 2004. We defined two types of cues possibly triggering a smoker to have a cigarette: peer cues and psychological cues. We used ordinary least square linear regressions to analyze smoking amount and response to peer and psychological distress cues.

Results:

We found a positive association between amount smoked and cue response: peer cues (1.06, 95%CI: 0.74–1.38) and psychological cues (0.44, 95%CI = 0.17–0.70). Response to psychological cues was lower among male smokers (−1.62, 95%CI = −2.26–−0.98), but response to psychological cues were higher among those who had senior high school level educations (0.96, 95%CI = 0.40–1.53) and who began smoking as a response to their moods (1.25, 95%CI = 0.68–1.82).

Conclusions:

These results suggest that both peer cues and psychological cues increase the possibility of contingent smoking, and should, therefore, be addressed by anti-smoking policies and anti-smoking programs. More specifically, special attention can be paid to help smokers avoid or counter social pressure to smoke and to help smokers resist the use of cigarettes to relieve distress.

Laboratory-based, cue-elicited craving and cue reactivity as predictors of naturally occurring smoking behavior

Cigarette craving, one hallmark sign of nicotine dependence, is often measured in laboratory settings using cue reactivity methods. How lab measures of cue reactivity relate to real world smoking behavior is unclear, particularly among non-treatment seeking smokers. Within a larger study of hormonal effects on cue reactivity (N=78), we examined the predictive relationship of cue reactivity to smoking, each measured in several ways. Results indicated that cue-evoked craving in response to stressful imagery, and to a lesser extent, in vivo smoking cues, significantly predicted smoking behavior during the week following testing. However, this predictive relationship was absent upon controlling for reactivity to neutral cues. Nicotine dependence may moderate the relationship between cue reactivity and actual smoking, such that this predictive relationship is less robust among highly dependent smokers than among smokers low in nicotine dependence. The question of whether cue-elicited craving predicts smoking among smokers not in treatment is best answered with a qualified yes, depending on how craving is manipulated and measured. Our findings highlight important methodological and theoretical considerations for cue reactivity research.

Abnormal pain response in pain-sensitive opiate addicts after prolonged abstinence predicts increased drug craving

RATIONALE

Craving is a primary feature of opiate addiction and is clinically significant because of its potential to trigger opiate use and relapse. Opiate use can also produce abnormal pain perception. We predicted that for opiate addicts (OAs), there may be an association between these two major features of addiction (drug craving and abnormal pain responses).

OBJECTIVES

To examine pain responses in abstinent opiate addicts in comparison with healthy controls using a cold-pressor test (CPT) and investigate the correlations of cue-induced drug craving with pain responses.

MATERIAL AND METHODS

Fifty-four abstinent OAs and 46 healthy subjects participated in the CPT, and the OAs were also exposed to heroin-related cues the day before the pain test. Outcome measures included pain-tolerance time, VAS ratings of pain intensity and distress, and (in the cue-exposure procedure) VAS ratings of heroin craving and anxiety.

RESULTS

In the CPT, abstinent addicts showed shorter pain-tolerance time (85.1 +/- 14.1 s vs. 133.7 +/- 16.7 s, p < 0.05) and higher ratings of pain distress (61 +/- 3.2 vs. 45.6 +/- 3.2, p < 0.01) compared to healthy controls. When we divided the addicts and controls into pain-sensitive (PS) and pain-tolerant (PT) groups by dichotomizing each group in terms of pain-tolerance time, we again found differences between the two PS groups (37.3 +/- 3.5 s vs. 57.4 +/- 5.1 s, p < 0.01 for pain-tolerance time; 66.7 +/- 3.2 vs. 52.4 +/- 3.3, p < 0.01 for distress ratings). For all participants, pain-tolerance time was negatively correlated with VAS ratings for pain intensity and distress. More importantly, the PS addicts reported greater cue-induced craving than the PT addicts (17.8 +/- 2.2 vs. 4.5 +/- 4.2, p < 0.05). For the addict group as a whole, pain distress (the affective aspect of pain) was positively correlated with intensity of cue-induced craving measured on a different day (r = 0.33, p = 0.01).

CONCLUSIONS

A hyperalgesic state persists for at least 5 months in abstinent OAs and is predictive of cue-induced craving. Longitudinal research is needed to clarify the direction of causation between hyperalgesia and opiate addiction.