Cigarette Cravings, Impulsivity, and the Brain

Examining the dynamics of tobacco dependence and psychosocial influences: A random intercept-latent transition analysis

Current literature on tobacco dependence often overlooks the nuanced interplay between individual and psychosocial factors over time. This study employed Random Intercept-Latent Transition Analysis to examine the progression of tobacco dependence among established smokers, focusing on how demographic variables and psychosocial influences impact transitions between dependence levels. Data from the Population Assessment of Tobacco and Health Study across three waves (n = 12,823; 45.3% female) were analyzed. Four latent classes were identified: Stable Low Dependence, Increasing Dependence, Worsening Dependence, and Stable High Dependence. Younger individuals and Hispanic populations were more likely to progress to higher dependence levels, with family and peer influences linked to worsening dependence. These findings highlight the need for personalized, culturally sensitive interventions that address specific stages of tobacco dependence, informing more effective tobacco control strategies that consider both individual and contextual factors.

Evaluating the Impact of Motivational Enhancement Therapy on Tobacco Cessation in Schizophrenia: A Comprehensive Review

Tobacco use is markedly prevalent among individuals with schizophrenia, presenting significant challenges to their physical health and psychiatric treatment. This comprehensive review evaluates the impact of motivational enhancement therapy (MET) on tobacco cessation in this population. Schizophrenia, a chronic mental disorder characterized by symptoms such as delusions and hallucinations, is frequently accompanied by high rates of smoking, which exacerbates health risks and complicates treatment regimens. MET, a client-centered approach rooted in motivational interviewing, aims to enhance intrinsic motivation for behavior change through empathetic and non-confrontational therapeutic sessions. This review synthesizes evidence from clinical studies on MET's effectiveness in promoting smoking cessation among individuals with schizophrenia. The review highlights the therapy's strengths, including its adaptability and client-focused nature, which are particularly beneficial for addressing the unique challenges faced by this population. It also discusses the broader health benefits of smoking cessation, such as improved physical health and enhanced efficacy of psychiatric medications. Despite promising results, the review identifies limitations and challenges in applying MET, such as potential barriers to implementation and the need for further research. In conclusion, MET offers a valuable intervention for tobacco cessation in individuals with schizophrenia, with the potential to significantly improve health outcomes and quality of life. Future research should focus on optimizing MET strategies and exploring their broader impacts on this vulnerable population.

Modulation of High-Frequency rTMS on Reward Circuitry in Individuals with Nicotine Dependence: A Preliminary fMRI Study

Although previous studies have shown that repetitive transcranial magnetic stimulation (rTMS) can ameliorate addictive behaviors and cravings, the underlying neural mechanisms remain unclear. This study aimed to investigate the effect of high-frequency rTMS with the left dorsolateral prefrontal cortex (L-DLPFC) as a target region on smoking addiction in nicotine-dependent individuals by detecting the change of spontaneous brain activity in the reward circuitry. We recruited 17 nicotine-dependence participants, who completed 10 sessions of 10 Hz rTMS over a 2-week period and underwent evaluation of several dependence-related scales, and resting-state fMRI scan before and after the treatment. Functional connectivity (FC) analysis was conducted with reward-related brain regions as seeds, including ventral tegmental area, bilateral nucleus accumbens (NAc), bilateral DLPFC, and bilateral amygdala. We found that, after the treatment, individuals showed reduced nicotine dependence, alleviated tobacco withdrawal symptoms, and diminished smoking cravings. The right NAc showed increased FC with right fusiform gyrus, inferior temporal gyrus (ITG), calcarine fissure and surrounding cortex, superior occipital gyrus (SOG), lingual gyrus, and bilateral cuneus. No significant FC changes were observed in other seed regions. Moreover, the changes in FC between the right NAc and the right ITG as well as SOG before and after rTMS were negatively correlated with changes in smoking scale scores. Our findings suggest that high-frequency L-DLPFC-rTMS reduces nicotine dependence and improves tobacco withdrawal symptoms, and the dysfunctional connectivity in reward circuitry may be the underlying neural mechanism for nicotine addiction and its therapeutic target.

Efficacy and safety of non-invasive brain stimulation techniques for the treatment of nicotine addiction: A systematic review of randomized controlled trials

Non-Invasive Brain Stimulation (NIBS) techniques seem to be effective in treating tobacco use disorder. We aimed to analyze what kinds of protocols are used to treat nicotine addiction in term of cessation and/or reduction and to evaluate the long-term effects of NIBS techniques. We searched PubMed, Scopus, and Web of Science for papers published, with combinations of the following search terms: "Non-invasive brain stimulation OR TMS OR transcranial magnetic stimulation OR tDCS OR transcranial direct current stimulation OR transcranial electrical stimulation OR TES AND Nicotine addiction". We conducted a preliminary search, which revealed papers on the topic. Articles were included in the review according to the following inclusion criteria: English language, publication in peer reviewed journals, articles about studies performed on non-invasive brain stimulations techniques, and RCT studies. Studies involving clinical populations with organic or psychiatric diseases were excluded. We found 280 articles. Of these, at the first screening and conducted by title and abstract, 63 studies were excluded after duplicates were removed (118). After the second screening conducted by full-text examination, 45 articles were excluded. Ten studies met the inclusion criteria and were included in the review. The clinical benefits of NIBS, including the fast onset and minor side effects, showed that this kind of treatment could be helpful in patients with a long history of smoking in terms of cessation and abstinence rates.

Patients with episodic migraine without aura have an increased rate of delayed discounting

OBJECTIVE

This study aimed to explore decision-making impulsivity and its neural mechanisms in patients with episodic migraine without aura (EMoA).

BACKGROUND

Previous evidence indicates increased impulsivity and altered reward processing in patients with chronic migraine and medication overuse; however, whether the same holds true for those with EMoA is unclear.

METHODS

Patients newly diagnosed with EMoA (n = 51) and healthy controls (HC, n = 45) were recruited. All participants completed delay discounting task, cognitive assessments, a questionnaire for headache profile, and resting-state function magnetic resonance imaging scans. Resting-state functional connectivity (RSFC) between the regions of interest and the entire brain was explored.

RESULTS

Patients with EMoA showed a steeper subjective discount rate than HCs (F = 4.74, p = .032), which was positively related to a history of migraines (r = .742, p < .001). RSFC among the ventral striatum (vSTR), ventromedial prefrontal cortex, and occipital cortex was lower in patients with EMoA than in control groups, which was correlated with history (r' = .294, p = .036) and subjective discount rate (r' = .380, p = .006). Additionally, discounting rates and RSFC between the vSTR and occipital regions were significantly abnormal in the triptan group than the non-triptan group. Mediating effect analysis indicated a significant mediating effect in the change in RSFC between the vSTR and occipital status, history of triptan use, and subjective discount rate.

CONCLUSION

This study further elucidated that an increase in delayed discounting rate exists in patients with EMoA and is related to the abnormality of the value processing network.

Electrophysiological signature of the interplay between habits and inhibition in response to smoking-related cues in individuals with a smoking habit: An event-related potential study

The rigid, stimulus-bound nature of drug seeking that characterizes substance use disorder (SUD) has been related to a dysregulation of motivational and early attentional reflexive and inhibitory reflective systems. However, the mechanisms by which these systems are engaged by drug-paired conditioned stimuli (CSs) when they promote the enactment of seeking habits in individuals with a SUD have not been elucidated. The present study aimed behaviourally and electrophysiologically to characterize the nature of the interaction between the reflexive and reflective systems recruited by CSs in individuals with a smoking habit. We measured the behavioural performance and associated event-related potentials (ERPs) of 20 individuals with a smoking habit and 20 controls, who never smoked regularly, in a modified Go/NoGo task during which smoking-related CSs, appetitive and neutral pictures, presented either in first or third-person visual perspective were displayed 250 ms before the Go/NoGo cue. We show that smoking-related cues selectively influence early incentive motivation-related attention bias (N2 after picture onset), motor readiness and behavioural inhibition (Go-P3, NoGo-P3 and Pc) of individuals with a smoking habit only when presented from a first-person visual perspective. These data together identify the neural signature of the aberrant engagement of the reflexive and reflective systems during the recruitment of an incentive habit by CSs presented as if they had been response-produced, that is, as conditioned reinforcers.

TOBACCO USE DISORDER AND DUAL DISORDERS Joint statement by the Spanish Psychiatry Society and the Spanish Dual Disorders Society

Tobacco Use Disorder (TUD) is a health problem of the first order in the world population, affecting a vulnerable population, such as people with other mental disorders, whose morbidity and mortality are increased as a result.

Relationship between smoking, narcissism, and impulsiveness among young women

Although the connection between smoking and individual differences has been recently recognized, the relationship between narcissistic personality traits and cigarette smoking has received less attention. The notion that personality traits can be associated with addictive behavior is influential in clinical practice. However, questions remain about specific interactions between smoking and personality characteristics that need empirical support to substantiate this hypothesis. This study thus identifies narcissistic and impulsive personality traits as precursors of smoking in a sample of tattooed individuals. In a cross-sectional study (N = 120), personality traits were assessed in young women (aged 18–35 years) using the narcissistic personality inventory and the Barratt Impulsivity Scale (BIS-11). The current study, using the regression analysis, has clearly demonstrated that young women who smoke have different personality characteristics as compared with women who do not smoke.

Gray matter volumes of the insula and anterior cingulate cortex and their dysfunctional roles in cigarette smoking

The salience network, including the insula and anterior cingulate cortex (ACC), has been implicated in nicotine addiction. Structural imaging studies have reported diminished insula and ACC gray matter volumes (GMVs) in smokers as compared to nonsmokers. However, it remains unclear how insula and ACC GMVs may relate to years of smoking, addiction severity, or behavioral traits known to dispose individuals to smoking. Here, with a dataset curated from the Human Connectome Project and voxel-based morphometry, we replicated the findings of smaller GMVs of the insula and medial prefrontal cortex, including the dorsal ACC and supplementary motor area (dACC/SMA), in (70 heavy < 209 light < 209 never) smokers matched in age, sex, and average daily num ber of drinks. The GMVs of the insula or dACC/SMA were not significantly correlated with years of smoking or Fagerstrom Test for Nicotine Dependence (FTND) scores. Heavy relative to never smokers demonstrated higher externalizing and internalizing scores, as evaluated by the NIH Emotion. In heavy smokers, the dACC/SMA but not insula GMV was positively correlated with both externalizing and internalizing scores. The findings together confirm volumetric changes in the salience network in heavy smokers and suggest potentially distinct dysfunctional roles of the insula and dACC/SMA in chronic smoking.

Maternal Urinary Cotinine Concentrations During Pregnancy Predict Infant BMI Trajectory After Birth: Analysis of 89617 Mother-Infant Pairs in the Japan Environment and Children's Study

BACKGROUND

Clinical or epidemiological conclusions remain undecided on the direct effects of active and second-hand smoking during pregnancy on childhood obesity. Urinary cotinine (UC) concentration, an accurate and quantitative marker for smoking, may elucidate the dose-dependent relationship between smoking during pregnancy and childhood obesity. To analyze the relationship between UC concentration and smoking questionnaire (SQ) classes for active and second-hand smoking in pregnant mothers and trajectory of infant Kaup index (body mass index: BMI).

METHODS

This multicenter prospective cohort study was conducted using a list-wise complete set of 35829 among 89617 mother-infant singleton pairs, recruited between 2011 and 2014, in the Japan Environment and Children's Study (JECS). Pairs were categorized according to UC levels (1 to 4 classes) or SQ (0 to 4 classes).

RESULTS

Maternal BMI at delivery was the highest in UC class 4 (highest). Maternal and paternal education of ≥16 years and annual household income were lowest in UC class 4. Infant BMI was lower at birth, but trends in BMI and ΔBMI were higher from six to 36 months step-wise in the UC classes. The above tendency was observed in the list-wise complete dataset but was emphasized after multiple imputations and corrections of cofounders. UC concentration in five SQ classes largely fluctuated, and the relationship between SQ classes and trends in BMI and ΔBMI was not statistically significant.

CONCLUSION

Infants from high UC mothers had a low BMI at birth, increasing from six to 36 months of age. UC concentrations, but not smoking questionnaire classes, predict infant BMI trajectory, suggesting that active and second-hand smoking affect child obesity in a dose-dependent manner.

Translation and psychometric validation of the Persian version of the Questionnaire on Smoking Urges for assessment of craving to smoke among university students

Background

Even though tobacco is one of the most preventable causes of death worldwide, it endangers more than 8 million people yearly. In this context, meta-analyses suggest that a significant part of the general Iranian population over 15 years of age smoke and that there is a need for good screening tools for smoking cravings and urges in Iran. The present study reported the translation and investigated the psychometric properties (i.e., factor structure, validity, and reliability) of the Persian version of the Questionnaire on Smoking Urges (QSU) with 12 items in the Iranian context.

Method

The translation process and content validity of the items were examined entirely in an expert panel using the Content Validity Index. The total sample of participants in which the translated version was tested consisted of 392 (172 female, 220 male, M_age = 22.31 years, SD = 2.90) university students who answered the QSU 12-item at the start of their participation in smoking cessation interventions. The QSU 12-item was firstly translated, then piloted using a subsample of 150 university students and finally validity and reliability of the instrument were investigated using a subsample of 242 participants. We tested the proposed models in the literature, that is, a 1-factor solution and a 2-factor solution with six items on each factor (Factor 1: desire/intention to smoke; Factor 2: relief of negative affect or withdrawal symptoms and anticipation of positive outcome). At last, we tested differences across differences in QSU-scores across different subgroups of individuals based on their demographics.

Results

The results suggested that, in contrast to past studies, a modified 2-factor model, using five items for Factor 1 and 7 items for Factor 2, was the best fitting model (CFI = .95, RMSEA = .09, CI = 90%). Additionally, the QSU 12-item Persian version showed good convergent and divergent validity, internal consistency (Factor 1 = .94, Factor 2 = .97), ICC (average measure ICC = .95, CI = 95%, F_{(391, 4301)} = 20.54, p < .001), concurrent validity (r = .71, p < .01), and discriminant validity (r = −.04, p > .05). Finally, subgroups based on gender, marital status, (un)employment, and educational level did not differed in their responses to the QSU 12-item.

Conclusion

The Persian version of the QSU 12-item has satisfactory psychometric properties and, with a slight modification, it can be considered as a reliable and valid method to estimate smoking urges in the Iranian population. Moreover, the QSU 12-item seems appropriate to measure urge for smoking among groups of individuals with different sociodemographic backgrounds. Importantly, the QSU 12-item differentiates individuals’ desire and intention to smoke from their anticipated relief of negative affect or withdrawal symptoms, which can be important for personalizing interventions targeting individuals who want to quit smoking.

Individual Determinants of Rest-Break Behavior in Occupational Settings

Aims: Work breaks improve well-being, productivity, and health. The aim of this study was to investigate the individual determinants of rest-break behavior during work using the theory of planned behavior (TPB). Methods: The association between attitude, control, and subjective norm and rest-break intention (i.e., taking rest breaks regularly), and rest-break behavior (average number of rest breaks/workhour) was analyzed with stepwise linear regression in a cross-sectional design. The study participants included 109 clerical employees, and 215 nurses. Results: Attitude and control were positively associated with rest-break intention. Intention and control were positively associated with rest-break behavior. The effect of intention was moderated by occupation, with intention being more weakly associated with rest-break behavior in nurses who had less behavioral control. Conclusions: Job control is the major predictor of rest-break behavior, with attitudes playing a minor role, and social norm playing no role. To increase rest-break behavior, a greater extent of job control is necessary.

Brain-Computer Interfaces, Open-Source, and Democratizing the Future of Augmented Consciousness

Accessibility, adaptability, and transparency of Brain-Computer Interface (BCI) tools and the data they collect will likely impact how we collectively navigate a new digital age. This discussion reviews some of the diverse and transdisciplinary applications of BCI technology and draws speculative inferences about the ways in which BCI tools, combined with machine learning (ML) algorithms may shape the future. BCIs come with substantial ethical and risk considerations, and it is argued that open source principles may help us navigate complex dilemmas by encouraging experimentation and making developments public as we build safeguards into this new paradigm. Bringing open-source principles of adaptability and transparency to BCI tools can help democratize the technology, permitting more voices to contribute to the conversation of what a BCI-driven future should look like. Open-source BCI tools and access to raw data, in contrast to black-box algorithms and limited access to summary data, are critical facets enabling artists, DIYers, researchers and other domain experts to participate in the conversation about how to study and augment human consciousness. Looking forward to a future in which augmented and virtual reality become integral parts of daily life, BCIs will likely play an increasingly important role in creating closed-loop feedback for generative content. Brain-computer interfaces are uniquely situated to provide artificial intelligence (AI) algorithms the necessary data for determining the decoding and timing of content delivery. The extent to which these algorithms are open-source may be critical to examine them for integrity, implicit bias, and conflicts of interest.

Inhibitory Control and Craving in Dual Disorders and Recurrent Substance Use. Preliminary Findings

Objective: In Dual Disorders (DD), which involves the co-occurrence of a disorder in substance use and a mental disorder, recurrent struggles with addictive behavior are frequent. Neuropsychological knowledge concerning the profile of inhibitory control and the irresistible urge to use substances (craving) within the DD patient group may contribute to the prevention of this recurrent addictive behavior. Methods: Inhibitory control and craving were assessed in 25 patients with DD and 25 healthy controls (HC). Inhibitory control tasks (Go/No-go task and Stop Signal Task) were performed combined with brain measurements (Event Related Potentials) mapping inhibitory control. Moreover, implicit and explicit measures concerning craving were administered. Statistical DD and HC comparisons, correlational and regression analyses on exploratory base were conducted. Results: DD patients committed more inhibitory control errors than HC when confronted with (alcohol) consumption-related picture stimuli. Furthermore, patients with DD showed higher levels of implicit and explicit craving. The number of inhibitory control errors was positively related to levels of implicit and explicit craving. Moreover, explicit craving and impulsivity (as a dimension of inhibitory control) predicted the severity of addictive behavior. Event Related Potential analyses did not show differences in inhibitory control-associated brain activity between DD patients and HC; both groups showed reduction of P300 amplitudes in response to alcohol pictures. Conclusions: Impulsivity and craving are elevated in DD patients and show predictive value for the severity of addictive behavior. One's level of impulsive action tendency may trigger less effort to control (recurrent) substance use. The findings may contribute to existing DD treatment indications by the promotion of impulse control training via "stop-think-act" methods for DD patients.

Neuroanatomical Correlates of Impulsive Choices and Risky Decision Making in Young Chronic Tobacco Smokers: A Voxel-Based Morphometry Study

Introduction: Impairments in the multifaceted neuropsychological construct of cognitive impulsivity are a main feature of chronic tobacco smokers. According to the literature, these cognitive impairments are relevant for the initiation and maintenance of the smoking behavior. However, the neuroanatomical correlates of cognitive impulsivity in chronic smokers remain under-investigated. Methods: A sample of 28 chronic smokers (mean age = 28 years) not affected by polysubstance dependence and 24 matched non-smoker controls was recruited. Voxel Based Morphometry (VBM) was employed to assess Gray Matter (GM) volume differences between smokers and non-smokers. The relationships between GM volume and behavioral manifestations of impulsive choices (5 trial adjusting delay discounting task, ADT-5) and risky decision making (Cambridge Gambling Task, CGT) were also investigated. Results: VBM results revealed GM volume reductions in cortical and striatal brain regions of chronic smokers compared to non-smokers. Additionally, smokers showed heightened impulsive choices (p < 0.01, Cohen's f = 0.50) and a riskier decision- making process (p < 0.01, Cohen's f = 0.40) compared to non-smokers. GM volume reductions in the left Anterior Cingulate Cortex (ACC) correlated with impaired impulsive and risky choices, while GM volume reductions in the left Ventrolateral Prefrontal Cortex (VLPFC) and Caudate correlated with heightened impulsive choices. Reduced GM volume in the left VLPFC correlated with younger age at smoking initiation (mean = 16 years). Conclusion: Smokers displayed significant GM volume reductions and related cognitive impulsivity impairments compared to non-smoker individuals. Longitudinal studies would be required to assess whether these impairments underline neurocognitive endophenotypes or if they are a consequence of tobacco exposure on the adolescent brain.

Response to nicotine following overnight smoking abstinence during short-term progesterone treatment in women

Preclinical and clinical literature suggest that sex hormones impact tobacco use behaviors in women. The goal of this double-blind crossover laboratory study was to examine the effect of oral exogenous progesterone (200 mg twice per day) versus placebo on nicotine response using measures of motor speed and cognitive function in women following overnight smoking abstinence. We hypothesized that increased progesterone would blunt the nicotine response whereby producing less change in motor speed and cognition in response to nicotine exposure. Female smokers, age 18-35, were randomized to participate in two 9-day crossover testing weeks. Participants completed a lab session following overnight abstinence where they were administered nicotine nasal spray and asked to complete measures of immediate memory (IMT), delayed memory (DMT), word recall (WR), and finger tapping speed (FT). After the first 9-day testing week, participants resumed smoking and returned the following month to complete the identical lab session in the crossover condition. Forty-seven women were included in this analysis (n = 47). We found no differences in the magnitude of response for IMT, DMT, and WR between conditions. For FT, women had a blunted response to nicotine during the placebo condition. When examining the association between hormone levels and relative performance, we found increases in DMT, WR, and FT but decreases in IMT during the progesterone condition. We observed differences between progesterone versus placebo in relative change in some measures of nicotine response following overnight abstinence. Future studies are needed to further characterize this response. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

A fractionated analysis of hot and cool self-regulation in cigarette smokers from different socioeconomic backgrounds

Smoking cigarettes and low socioeconomic status (SES) are both related to impaired cognition. However, it is unknown whether people of lower SES, who comprise most tobacco smokers worldwide, are more susceptible to cognitive impairment associated with smoking. In this non-randomized, cross-sectional study we investigated the effects of cigarette smoking, SES and their interaction on dissociable executive or “cool” and “hot” measures of behavioural self-regulation. Participants (n = 80) were selected among young physically and mentally healthy smokers and non-smokers who had graduated high school and were from different SES backgrounds. Cool self-regulation was measured by executive function tasks that tap inhibition, updating, shifting, dual tasking, planning, access to long-term memory (semantic fluency), and working memory capacity. Hot measures assessed self-reported impulsivity, delay discounting and risk taking. Exposure to tobacco (cotinine, exhaled carbon monoxide, tobacco dependence, cigarette consumption) was assessed to determine to what extent it mediated the cognitive effects of smoking. Nicotine abstinence and its acute effects were controlled, as were sex, age, schooling, and psychiatric symptoms despite the fact that smokers and non-smokers were selected as being as similar as possible in these demographic characteristics. Lower SES (less years of parental schooling) was associated with worse performance on tasks that measured all cool domains except dual tasking and fluency, while smoking status was related to impaired delayed discounting and impulsivity (hot domains), effects that were not mediated by tobacco exposure. Smoking and SES, however, did not interact. In short, impaired performance in measures of most cool skills was associated with SES irrespective of smoking status; in contrast, regardless of SES, smokers showed specific impairment in hot self-regulation domains (more difficulty resisting immediate temptations and weighing future consequences of actions). Possible explanations for the lack of mediation of tobacco exposure on hot skills of smokers are discussed.

Increased Connectivity Between the Nucleus Accumbens and the Default Mode Network in Patients With Schizophrenia During Cigarette Cravings

Objective: Compared to the general population, tobacco smoking cessation rates are lower in populations with schizophrenia. Unfortunately, the potential neurophysiologic mechanisms underlying these low cessation rates in schizophrenia have been seldom studied using functional neuroimaging. Recently, it has been shown that tobacco cravings are increased in smokers with schizophrenia compared to smokers with no comorbid psychiatric disorder. Given the critical role of the brain reward system in the neurobiology of addiction, we sought to examine the functional connectivity of core regions of this system in smokers with schizophrenia during the viewing of appetitive smoking cues. Methods: Smokers with (n = 18) and without (n = 24) schizophrenia were scanned using functional magnetic resonance imaging while viewing appetitive cigarette images. Functional connectivity analyses were performed using the bilateral nucleus accumbens as the seed regions. Results: Smokers with schizophrenia and smokers with no psychiatric comorbidity did not differ in subjective cravings in response to appetitive smoking cues. However, in smokers with schizophrenia relative to control smokers, we found an increased connectivity between the nucleus accumbens and regions involved in the default mode network (e.g., middle temporal gyrus and precuneus), which are involved in self-referential processes. Moreover, a positive correlation was observed between the left nucleus accumbens and left middle temporal gyrus connectivity and cigarette cravings across both groups of smokers. Conclusions: These results highlight a key role of the nucleus accumbens in cigarette craving in schizophrenia and suggest that the subjective valuation of cigarette cues is increased in this population. Similar neurofunctional studies on cravings for other psychoactive substances in schizophrenia are warranted.

Neural correlates of appetitive extinction in humans

Appetitive extinction receives attention as an important model for the treatment of psychiatric disorders. However, in humans, its underlying neural correlates remain unknown. To close this gap, we investigated appetitive acquisition and extinction with fMRI in a 2-day monetary incentive delay paradigm. During appetitive conditioning, one stimulus (CS+) was paired with monetary reward, while another stimulus (CS−) was never rewarded. Twenty-four hours later, subjects underwent extinction, in which neither CS was reinforced. Appetitive conditioning elicited stronger skin conductance responses to the CS+ as compared with the CS−. Regarding subjective ratings, the CS+ was rated more pleasant and arousing than the CS− after conditioning. Furthermore, fMRI-results (CS+ − CS−) showed activation of the reward circuitry including amygdala, midbrain and striatal areas. During extinction, conditioned responses were successfully extinguished. In the early phase of extinction, we found a significant activation of the caudate, the hippocampus, the dorsal and ventral anterior cingulate cortex (dACC and vACC). In the late phase, we found significant activation of the nucleus accumbens (NAcc) and the amygdala. Correlational analyses with subjective ratings linked extinction success to the vACC and the NAcc, while associating the dACC with reduced extinction. The results reveal neural correlates of appetitive extinction in humans and extend assumptions from models for human extinction learning.

Cigarette Use and Striatal Dopamine D2/3 Receptors: Possible Role in the Link between Smoking and Nicotine Dependence

BACKGROUND

Cigarette smoking induces dopamine release in the striatum, and smoking- or nicotine-induced ventral striatal dopamine release is correlated with nicotine dependence. Smokers also exhibit lower dopamine D2/3 receptor availability in the dorsal striatum than nonsmokers. Negative correlations of striatal dopamine D2/3 receptor availability with smoking exposure and nicotine dependence, therefore, might be expected but have not been tested.

METHODS

Twenty smokers had positron emission tomography scans with [¹⁸F]fallypride to measure dopamine D2/3 receptor availability in ventral and dorsal regions of the striatum and provided self-report measures of recent and lifetime smoking and of nicotine dependence.

RESULTS

As reported before, lifetime smoking was correlated with nicotine dependence. New findings were that ventral striatal dopamine D2/3 receptor availability was negatively correlated with recent and lifetime smoking and also with nicotine dependence.

CONCLUSION

The results suggest an effect of smoking on ventral striatal D2/3 dopamine receptors that may contribute to nicotine dependence.

Increased ventro-medial prefrontal activations in schizophrenia smokers during cigarette cravings

BACKGROUND

Highly prevalent in schizophrenia, tobacco smoking substantially increases the risk of cardiac-related death. Compared to the general population, tobacco smoking cessation rates are lower in schizophrenia. Unfortunately, the reasons for these low cessation rates remain poorly understood. Recently, it has been shown that tobacco cravings are increased in schizophrenia smokers compared to smokers with no comorbid psychiatric disorder. In view of these results, we sought to examine - for the first time - the neurophysiologic responses elicited by cigarette cues in schizophrenia smokers. We hypothesized that cigarettes cues would elicit increased activations in brain regions involved in drug cravings in schizophrenia smokers relative to control smokers.

METHODS

Smokers with (n=18) and without (n=24) schizophrenia (DSM-IV criteria) were scanned using functional magnetic resonance imaging (fMRI) while viewing appetitive cigarette images.

RESULTS

Schizophrenia smokers and smokers with no psychiatric comorbidity did not differ in subjective cravings in response to appetitive smoking cues. However, in schizophrenia smokers relative to control smokers, we found that appetitive cigarette cues triggered increased activations of the bilateral ventro-medial prefrontal cortex, a core region of the brain reward system. Moreover, a negative correlation was observed between cigarette cravings and activations of the right ventro-medial prefrontal cortex in schizophrenia smokers.

DISCUSSION

The current results highlight a key role of the brain reward system in cigarette craving in schizophrenia, and suggest that the neurophysiologic mechanisms involved in the regulation of cue-induced cigarette craving are impaired in this population.

Neuroscience of drug craving for addiction medicine: From circuits to therapies

Drug craving is a dynamic neurocognitive emotional-motivational response to a wide range of cues, from internal to external environments and from drug-related to stressful or affective events. The subjective feeling of craving, as an appetitive or compulsive state, could be considered a part of this multidimensional process, with modules in different levels of consciousness and embodiment. The neural correspondence of this dynamic and complex phenomenon may be productively investigated in relation to regional, small-scale networks, large-scale networks, and brain states. Within cognitive neuroscience, this approach has provided a long list of neural and cognitive targets for craving modulations with different cognitive, electrical, or pharmacological interventions. There are new opportunities to integrate different approaches for carving management from environmental, behavioral, psychosocial, cognitive, and neural perspectives. By using cognitive neuroscience models that treat drug craving as a dynamic and multidimensional process, these approaches may yield more effective interventions for addiction medicine.