Brian L. Carter

The effects of depressed mood on smoking cessation: Mediation by postcessation self-efficacy

This study evaluated the relationship between precessation depressed mood and smoking abstinence and assessed the mediation of this effect by postcessation self-efficacy, urges to smoke, nicotine withdrawal, and coping behavior. The sample included 121 smokers previously treated in a randomized controlled trial involving behavior therapy and the nicotine patch. The results showed that precessation depressed mood was inversely related to 6-month abstinence. This effect remained significant after controlling for treatment, possible depression history, baseline smoking rates, and several other demographic factors. Postcessation self-efficacy, at the 2-, 4-, and 8-week postquit assessments, was the strongest mediator of the effects of precessation depressed mood on abstinence, accounting for 32%, 38%, and 48% of the effect of mood on abstinence, respectively.

A Psychometric Evaluation of Cigarette Stimuli Used in a Cue Reactivity Study

Laboratory studies have demonstrated that cigarette smokers react with significant subjective and autonomic responses (e.g., increased craving and increased heart rate) in the presence of stimuli associated with smoking. Although cue reactivity effects are typically robust, a number of methodological considerations make interpretation and design of cue reactivity studies problematic. Previous research has paid scant attention to the psychometric properties of the cigarette cues presented, and standard cues would enhance comparison and synthesis of studies. In the present study, we evaluated 12 cigarette photos (compared with positive, negative, and neutral photos), used in a separate study, for their ability to evoke self-report of craving in both nicotine-deprived and nondeprived smokers. These photos performed as expected, with cigarette pictures evoking significantly higher craving than neutral pictures and deprived smokers showing a trend toward higher craving than nondeprived smokers. The cigarette picture set was evaluated for internal consistency (Cronbachs alpha = .97) as a 12-item scale and further reduced to multiple 2-item scales with reliability estimates ranging from .70 to .93. A cluster analysis of all pictures showed that, when rated for craving, cigarette pictures clustered together, indicating they had distinct properties compared with positive, negative, and neutral pictures. Effect sizes were calculated for each cigarette picture in both deprived and nondeprived smokers. The craving effect sizes ranged from .57 to .98 for nondeprived smokers, and from .61 to .99 for deprived smokers. The analyses suggest these cigarette pictures have excellent psychometric properties for use in future cue reactivity studies.

Assessing reactivity to virtual reality alcohol based cues

The use of virtual reality (VR) programs in behavioral science research has been gaining prominence over the past several years. In the field of substance abuse, VR cue reactivity programs have been successfully tested for feasibility in nicotine and cocaine dependent samples. Seeking to expand VR applications in alcohol cue research, a novel VR alcohol cue reactivity assessment system incorporating visual, auditory, and olfactory stimuli was developed and tested. In a controlled trial, 40 non-treatment-seeking drinkers with alcohol use disorders were exposed to VR alcohol cue environments. Subjective craving, attention to alcohol cues, and level of presence (realism of experience) in VR were assessed across the environments. Overall, subjective craving for alcohol increased across the VR alcohol-related cue environments versus VR neutral cue environments. Participants reported high levels of presence in VR, indicating that the environments were perceived as realistic and compelling. These initial findings support the use of VR based cue reactivity environments for use in alcohol cue-based treatment and research.

The Effects of Smoking Deprivation and Nicotine Administration on Emotional Reactivity

Although converging lines of evidence suggest that nicotine and mood are related at a fundamental biological level, this link has not been reliably demonstrated in laboratory studies. In this study, startle probe methodology was used to examine the effects of nicotine administration and deprivation on emotional processes associated with motivation. Smokers (N = 115) completed four laboratory sessions crossing deprivation (12-hr deprived vs. nondeprived) with nicotine spray (active vs. placebo). Participants viewed affective pictures (positive, negative, neutral) and pictures involving cigarette cues, while startle probes were administered. Deprivation decreased startle responding to cigarette cues, suggesting an activation of appetitive processes. Nicotine administration suppressed overall startle responding during deprivation. In addition, during deprivation, random exposure to negative stimuli over two blocks of trials resulted in decreased adaptation of the startle response, suggesting that some sensitization to negative emotional cues may take place during nicotine withdrawal. These effects are consistent with formulations of addiction, stressing that withdrawal may both increase the reinforcement salience of smoking stimuli and decrease habituation to negative emotional stimuli.

A meta-analytic review of the CYP2A6 genotype and smoking behavior

Individuals who carry variant alleles of the CYP2A6 gene are poor metabolizers of nicotine and are believed to be more sensitive to nicotines aversive effects than those with normal alleles. This sensitivity is hypothesized to exert a protective effect against smoking initiation and lead to lower cigarette consumption among smokers with variant alleles. Although early studies found an association between variant CYP2A6 alleles and smoking behavior, more recent studies have not. A meta-analysis was conducted to help resolve these conflicting results. A literature search produced 11 studies providing information on CYP2A6 genotyping in smokers or nonsmoking control subjects. Participants were classified as smokers (ever-smokers or current smokers) or nonsmokers (former or never-smokers), and as carrying normal CYP2A6 genes or one or more variant alleles. Information regarding cigarette consumption also was included. Effect sizes were calculated from each study and then aggregated into an overall effect size. This analysis failed to find any empirical evidence of a relationship between variant CYP2A6 alleles and smoking status (n=4091) or cigarette consumption (n=1537). Although these results suggest the CYP2A6 gene is not associated with smoking behavior, the use of broad smoking status classifications (e.g., ever- vs. never-smoking), which fail to account for the complex nature of gene expression (e.g., gene-gene interactions), may have obscured the relatively modest genetic influences that might have been present. What role, if any, the CYP2A6 gene plays in smoking behavior will be understood only if future research addresses these methodological concerns.

Reactivity to cannabis cues in virtual reality environments.

Abstract Virtual reality (VR) cue environments have been developed and successfully tested in nicotine, cocaine, and alcohol abusers. Aims in the current article include the development and testing of a novel VR cannabis cue reactivity assessment system. It was hypothesized that subjective craving levels and attention to cannabis cues would be higher in VR environments with cannabis cues compared to VR neutral environments. Twenty nontreatment-seeking current cannabis smokers participated in the VR cue trial. During the VR cue trial, participants were exposed to four virtual environments that contained audio, visual, olfactory, and vibrotactile sensory stimuli. Two VR environments contained cannabis cues that consisted of a party room in which people were smoking cannabis and a room containing cannabis paraphernalia without people. Two VR neutral rooms without cannabis cues consisted of a digital art gallery with nature videos. Subjective craving and attention to cues were significantly higher in the VR cannabis environments compared to the VR neutral environments. These findings indicate that VR cannabis cue reactivity may offer a new technology-based method to advance addiction research and treatment.

What virtual reality research in addictions can tell us about the future of obesity assessment and treatment.

Virtual reality (VR), a system of human-computer interaction that allows researchers and clinicians to immerse people in virtual worlds, is gaining considerable traction as a research, education, and treatment tool. Virtual reality has been used successfully to treat anxiety disorders such as fear of flying and post-traumatic stress disorder, as an aid in stroke rehabilitation, and as a behavior modification aid in the treatment of attention deficit disorder. Virtual reality has also been employed in research on addictive disorders. Given the strong evidence that drug-dependent people are highly prone to use and relapse in the presence of environmental stimuli associated with drug use, VR is an ideal platform from which to study this relationship. Research using VR has shown that drug-dependent people react with strong craving to specific cues (e.g., cigarette packs, liquor bottles) as well as environments or settings (e.g., bar, party) associated with drug use. Virtual reality has also been used to enhance learning and generalization of relapse prevention skills in smokers by reinforcing these skills in lifelike environments. Obesity researchers and treatment professionals, building on the lessons learned from VR research in substance abuse, have the opportunity to adapt these methods for investigating their own research and treatment questions. Virtual reality is ideally suited to investigate the link between food cues and environmental settings with eating behaviors and self-report of hunger. In addition, VR can be used as a treatment tool for enhancing behavior modification goals to support healthy eating habits by reinforcing these goals in life-like situations.

Assessing Craving in Young Adult Smokers Using Virtual Reality

Cigarette smokers, when confronted with cues associated with smoking, evidence strong reactions, including increased craving. These reactions have not been extensively studied in young adult smokers, a group that research suggests may respond differently than adults or adolescent smokers. We used virtual reality, which presents a complex array of smoking cues that may be particularly salient to young adult smokers, and measured self-report of craving. Young adult smokers responded strongly to these cues and, unlike adults, did not return to a baseline of craving following cue exposure, suggesting young adult smokers differ from other smokers in terms of cue responses.

Cue Reactivity in Virtual Reality: The Role of Context

Cigarette smokers in laboratory experiments readily respond to smoking stimuli with increased craving. An alternative to traditional cue-reactivity methods (e.g., exposure to cigarette photos), virtual reality (VR) has been shown to be a viable cue presentation method to elicit and assess cigarette craving within complex virtual environments. However, it remains poorly understood whether contextual cues from the environment contribute to craving increases in addition to specific cues, like cigarettes. This study examined the role of contextual cues in a VR environment to evoke craving. Smokers were exposed to a virtual convenience store devoid of any specific cigarette cues followed by exposure to the same convenience store with specific cigarette cues added. Smokers reported increased craving following exposure to the virtual convenience store without specific cues, and significantly greater craving following the convenience store with cigarette cues added. However, increased craving recorded after the second convenience store may have been due to the pre-exposure to the first convenience store. This study offers evidence that an environmental context where cigarette cues are normally present (but are not), elicits significant craving in the absence of specific cigarette cues. This finding suggests that VR may have stronger ecological validity over traditional cue reactivity exposure methods by exposing smokers to the full range of cigarette-related environmental stimuli, in addition to specific cigarette cues, that smokers typically experience in their daily lives.

Using virtual reality to assess young adult smokers' attention to cues.

Cigarette smokers, when confronted with cues associated with smoking, evidence strong reactions, including increased attentional bias toward those smoking-related cues. These reactions have not been extensively studied in young adult smokers, a group that research suggests may respond differently than adults or adolescent smokers. Furthermore, the impact of olfactory cues, such as cigarette smoke, on attentional bias has not been explored in young adult smokers. In this pilot study, 20 nicotine-dependent young adult smokers were randomized to receive scent cues or no scent cues and were exposed to four virtual reality (VR) rooms containing sensory and social content, including smoking or neutral cues. Participants entered a neutral VR room, followed by two different smoking VR rooms, and closed with the same neutral room. Subjective attention to smoking cues and thoughts about smoking responses were recorded upon exiting each room. Significant increases in attention to cues and thoughts about smoking were found when young adult smokers were exposed to VR smoking environments, but the inclusion of olfactory cues did not result in significantly higher attention to cues or thoughts about smoking. Results suggest that while further research is necessary to understand the impact of olfactory cues, VR appears to be an effective methodology for cue exposure studies exploring attentional bias in young adult smokers.