Neural correlates of response inhibition and cigarette smoking in late adolescence

Neurogenetic underpinnings of nicotine use severity: Integrating the brain transcriptomes and GWAS variants via network approaches

Our study focused on human brain transcriptomes and the genetic risks of cigarettes per day (CPD) to investigate the neurogenetic mechanisms of individual variation in nicotine use severity. We constructed whole-brain and intramodular region-specific coexpression networks using BrainSpan's transcriptomes, and the genomewide association studies identified risk variants of CPD, confirmed the associations between CPD and each gene set in the region-specific subnetworks using an independent dataset, and conducted bioinformatic analyses. Eight brain-region-specific coexpression subnetworks were identified in association with CPD: amygdala, hippocampus, medial prefrontal cortex (MPFC), orbitofrontal cortex (OPFC), dorsolateral prefrontal cortex, striatum, mediodorsal nucleus of the thalamus (MDTHAL), and primary motor cortex (M1C). Each gene set in the eight subnetworks was associated with CPD. We also identified three hub proteins encoded by GRIN2A in the amygdala, PMCA2 in the hippocampus, MPFC, OPFC, striatum, and MDTHAL, and SV2B in M1C. Intriguingly, the pancreatic secretion pathway appeared in all the significant protein interaction subnetworks, suggesting pleiotropic effects between cigarette smoking and pancreatic diseases. The three hub proteins and genes are implicated in stress response, drug memory, calcium homeostasis, and inhibitory control. These findings provide novel evidence of the neurogenetic underpinnings of smoking severity.

Knowledge of smoking and influencing factors among school-going adolescents in Timor-Leste

OBJECTIVES

Knowledge of smoking is a protective factor for adolescent smoking. This study is the first to examine sociodemographic and lifestyle factors associated with adolescents' knowledge of smoking in Timor-Leste. It is also a pioneering investigation into the ways in which exposure to anti-tobacco messages and health warnings on cigarette packages, and involvement in smoking-related education at schools and home mediate the relationship between school grade levels and smoking knowledge.

METHODS

Data were obtained from the Global Youth Tobacco Survey Timor-Leste. Ordered logistic regressions were used to examine the associations between knowledge of smoking and sociodemographic, and lifestyle factors. Structural equation modelling was utilized to explore the mediating effects.

RESULTS

Adolescents were less likely to have high knowledge of smoking if they were lower-secondary students, were males, had unemployed parents and had no closest friends who smoked. The relationship between grade levels and smoking knowledge was partly mediated by awareness of anti-tobacco messages on mass media, school education about the dangers of smoking and family discussion about smoking.

CONCLUSIONS

Sociodemographic and lifestyle factors play an important role in determining knowledge of smoking among adolescents. To some extent, awareness-, education- and family-related variables explain how grade levels affect smoking knowledge.

Brain modular connectivity interactions can predict proactive inhibition in smokers when facing smoking cues

Proactive inhibition is a critical ability for smokers who seek to moderate or quit smoking. It allows them to pre-emptively refrain from seeking and using nicotine products, especially when facing salient smoking cues in daily life. Nevertheless, there is limited knowledge on the impact of salient cues on behavioural and neural aspects of proactive inhibition, especially in smokers with nicotine withdrawal. Here, we seek to bridge this gap. To this end, we recruited 26 smokers to complete a stop-signal anticipant task (SSAT) in two separate sessions: once in the neutral cue condition and once in the smoking cue condition. We used graph-based modularity analysis to identify the modular structures of proactive inhibition-related network during the SSAT and further investigated how the interactions within and between these modules could be modulated by different proactive inhibition demands and salient smoking cues. Findings pointed to three stable brain modules involved in the dynamical processes of proactive inhibition: the sensorimotor network (SMN), cognitive control network (CCN) and default-mode network (DMN). With the increase in demands, functional connectivity increased within the SMN, CCN and between SMN-CCN and decreased within the DMN and between SMN-DMN and CCN-DMN. Salient smoking cues disturbed the effective dynamic interactions of brain modules. The profiles for those functional interactions successfully predicted the behavioural performance of proactive inhibition in abstinent smokers. These findings advance our understanding of the neural mechanisms of proactive inhibition from a large-scale network perspective. They can shed light on developing specific interventions for abstinent smokers.

People with tobacco use disorder exhibit more prefrontal activity during preparatory control but reduced anterior cingulate activity during reactive control

Reduced inhibitory control and a hypersensitivity to reward are key deficits in drug dependents; however, they tend to be studied in isolation. Here, we seek to understand the neural processes underlying control over reward and how this is different in people with a tobacco use disorder (pTUD). A novel variant of the monetary incentive delay task was performed by pTUD (n = 20) and non-smokers (n = 20), where we added a stop-signal component such that participants had to inhibit prepotent responses to earn a larger monetary reward. Brain activity was recorded using functional magnetic resonance imaging (fMRI). We estimated stop signal reaction times (SSRTs), an indicator of impulsivity, and correlated these with brain activity. Inhibitory accuracy scores did not differ between the control group and pTUD. However, pTUD had slower SSRTs, suggesting that they may find it harder to inhibit responses. Brain data revealed that pTUD had greater preparatory control activity in the middle frontal gyrus and inferior frontal gyrus prior to successful inhibitions over reward. In contrast, non-smokers had greater reactive control associated with more activity in the anterior cingulate cortex during these successful inhibitions. SSRT-brain activity correlations revealed that pTUD engaged more control-related prefrontal brain regions when SSRTs are slower. Overall, while the inhibition accuracy scores were similar between groups, differential neural processes and strategies were used to successfully inhibit a prepotent response. The findings suggest that increasing preparatory control in pTUD may be one possible treatment target in order to increase inhibitory control over reward.

Altered resting-state electroencephalography microstate characteristics in young male smokers

The development of nicotine addiction was associated with the abnormalities of intrinsic functional networks during the resting state in young adult smokers. As a whole-brain imaging approach, EEG microstate analysis treated multichannel EEG recordings as a series of quasi-steady microscopic states which were related to the resting-state networks (RSNs) found by fMRI. The aim of this study was to examine whether the resting-state EEG microstate analysis may provide novel insights into the abnormal temporal properties of intrinsic brain activities in young smokers. We used 64-channel resting-state EEG datasets to investigate alterations in microstate characteristics between twenty-five young smokers and 25 age- and gender-matched non-smoking controls. Four classic EEG microstates (microstate A, B, C, and D) were obtained, and the four temporal parameters of each microstate were extracted, i.e., duration, occurrence, coverage, and transition probabilities. Compared with non-smoking controls, young smokers showed decreased occurrence of microstate C and increased duration of microstate D. Furthermore, both the duration and coverage of microstate D were significantly negatively correlated with Fagerstrom Test of Nicotine Dependence (FTND) in young smoker group. The complex changes in the microstate time-domain parameters might correspond to the abnormalities of RSNs in analyses of FC measured with fMRI in the previous studies and indicate the altered specific brain functions in young smokers. Microstate D could be potentially represented as a selective biomarker for predicting the dependence degree of adolescent smokers on cigarettes. These results suggested that EEG microstate analysis might detect the deviant functions of large-scale cortical activities in young smokers and provide a new perspective for the study of brain networks of adolescent smokers.

Chronic tobacco smoking, impaired reward-based decision-making, and role of insular cortex: A comparison between early-onset smokers and late-onset smokers

INTRODUCTION

The literature suggests that tobacco smoking may have a neurotoxic effect on the developing adolescent brain. Particularly, it may impair the decision-making process of early-onset smokers (<16 years), by rendering them more prone to impulsive and risky choices toward rewards, and therefore more prone to smoking relapses, in comparison to late-onset smokers (≥16 years). However, no study has ever investigated reward-based decision-making and structural brain differences between early-onset smokers and late-onset smokers.

METHODS

Computerized measures of reward-based decision-making [Cambridge Gambling Task (CGT); 5-trials adjusting delay discounting task (ADT-5)] were administered to 11 early-onset smokers (mean age at regular smoking initiation = 13.2 years), 17 late-onset smokers (mean age at regular smoking initiation = 18.0 years), and 24 non-smoker controls. Voxel-based morphometry (VBM) was utilized to investigate the gray matter (GM) and white matter (WM) volume differences in fronto-cortical and striatal brain regions between early-onset smokers, late-onset smokers, and non-smokers.

RESULTS

Early-onset smokers displayed a riskier decision-making behavior in comparison to non-smokers as assessed by the CGT (p < 0.01, Cohen's f = 0.48). However, no significant differences (p > 0.05) in reward-based decision-making were detected between early-onset smokers and late-onset smokers. VBM results revealed early-onset smokers to present lower GM volume in the bilateral anterior insular cortex (AI) in comparison to late-onset smokers and lower WM volume in the right AI in comparison to late-onset smokers.

CONCLUSION

Impairments in reward-based decision-making may not be affected by tobacco smoking initiation during early adolescence. Instead, lower GM and WM volume in the AI of early-onset smokers may underline a vulnerability to develop compulsive tobacco seeking and smoking behavior during adulthood.

Effects of substance misuse on inhibitory control in patients with attention-deficit/hyperactivity disorder

Patients with attention‐deficit/hyperactivity disorder (ADHD) are often diagnosed with comorbid substance misuse (SM), which is associated with poor treatment efficacy. Although literature indicates similar inhibitory control deficits in both conditions, it is unclear whether SM in ADHD exaggerates pre‐existing deficits, with additive or distinct impairments in patients. Our aim was to examine SM effects on inhibitory control in ADHD. Behavioural and functional magnetic resonance imaging (fMRI) data from a stop‐signal task were compared across ADHD patients with and without SM (ADHD + SM and ADHD‐only, respectively) and controls (n = 33/group; 79 males, mean age 18.02 ± 2.45). To limit substance use disorder (SUD) trait effects, groups were matched for parental SUD. Overall, we found worse performance for ADHD‐only and/or ADHD + SM compared with controls but no difference between the ADHD groups. Moreover, the ADHD groups showed decreased frontostriatal and frontoparietal activity during successful and failed stop trials. There were no differences between the ADHD groups in superior frontal nodes, but there was more decreased activation in temporal/parietal nodes in ADHD‐only compared with ADHD + SM. During go‐trials, ADHD + SM showed decreased activation in inferior frontal nodes compared with ADHD‐only and controls. Findings during response inhibition showed deficits in inhibition and attentional processes for ADHD patients with and without SM. Despite no evidence for SM effects during response inhibition, results during go‐trials suggest distinct effects on nodes that are associated with several executive functions. Future studies should investigate whether distinct deficits in ADHD + SM relate to poor treatment results and can direct development of distinct ADHD treatment strategies for these patients.

Neural substrates of deficient cognitive control in individuals with severe internet gaming disorder

BACKGROUND AND AIMS

Internet gaming disorder (IGD) is rapidly becoming a worldwide health concern. The prefrontal-subcortical model of self-regulation emphasizes that an impaired prefrontal cognitive control system and an overwhelming subcortical reward-seeking system are both crucial factors in health problems, including addiction. This study focused on the cognitive control system of IGD, aiming to investigate whether cognitive control is altered and the underlying neural correlates in college students with IGD.

METHODS

Thirty college students with IGD and twenty-five matched healthy controls were asked to complete a stop-signal task that measures cognitive control while being monitored by functional magnetic resonance imaging (fMRI).

RESULTS

Compared to the controls, only the college students with severe IGD, rather than those with mild IGD, had deficient brain activity involved in inhibitory control and response execution (specifically, the inferior frontal gyrus, anterior cingulate cortex and primary motor cortex); this result implies that cognitive control deficits are closely linked to addiction severity in individuals with IGD. Regarding performance monitoring function, college students with IGD exhibited unabated behavioral and brain activity, as did the control group.

CONCLUSIONS

Combined with our previous finding that the subcortical reward system was enhanced in individuals with IGD, the present findings extend the prefrontal-subcortical model of self-regulation from the perspective of IGD in a college student population and thus provide useful insight for the effective prevention and treatment of IGD.

Subtypes of inhibitory and reward activation associated with substance use variation in adolescence: A latent profile analysis of brain imaging data

The present study identified subgroups based on inhibitory and reward activation, two key neural functions involved in risk-taking behavior, and then tested the extent to which subgroup differences varied by age, sex, behavioral and familial risk, and substance use. Participants were 145 young adults (18-21 years old; 40.0% female) from the Michigan Longitudinal Study. Latent profile analysis (LPA) was used to establish subgroups using task-based brain activations. Demographic and substance use differences between subgroups were then examined in logistic regression analyses. Whole-brain task activations during a functional magnetic resonance imaging go/no-go task and monetary incentive delay task were used to identify beta weights as input for LPA modeling. A four-class model showed the best fit with the data. Subgroups were categorized as: (1) low inhibitory activation/moderate reward activation (39.7%), (2) moderate inhibitory activation/low reward activation (22.7%), (3) moderate inhibitory activation/high reward activation (25.2%), and (4) high inhibitory activation/high reward activation (12.4%). Compared with the other subgroups, Class 2 was older, less likely to have parental alcohol use disorder, and had less alcohol use. Class 4 was the youngest and had greater marijuana use. Classes 1 and 3 did not differ significantly from the other subgroups. These findings demonstrate that LPA applied to brain activations can be used to identify distinct neural profiles that may explain heterogeneity in substance use outcomes and may inform more targeted substance use prevention and intervention efforts.

Bidirectional links between adolescent brain function and substance use moderated by cognitive control

BACKGROUND

No clear consensus exists as to whether neurodevelopmental abnormalities among substance users reflect predisposing neural risk factors, neurotoxic effects of substances, or both. Using a longitudinal design, we examined developmental patterns of the bidirectional links between neural mechanisms and substance use throughout adolescence.

METHOD

167 adolescents (aged 13-14 years at Time 1, 53% male) were assessed annually four times. Risk-related neural processing was assessed by blood-oxygen-level-dependent responses in the insula during a lottery choice task, cognitive control by behavioral performance during the Multi-Source Interference Task, and substance use by adolescents' self-reported cigarette, alcohol, and marijuana use.

RESULTS

Latent change score modeling indicated that greater substance use predicted increased insula activation during risk processing, but the effects of insula activation on changes in substance use were not significant. The coupling effect from substance use to insula activation was particularly strong for adolescents with low cognitive control, which supports the theorized moderating role of cognitive control.

CONCLUSIONS

Our results elucidate how substance use may alter brain development to be biased toward maladaptive decision-making, particularly among adolescents with poor cognitive control. Furthermore, the current findings underscore that cognitive control may be an important target in the prevention and treatment of adolescent substance use given its moderating role in the neuroadaptive effects of substance use on brain development.

Environmental Tobacco Smoke Exposure and Brain Functioning Associated with Smoking Cue-Reactivity and Inhibitory Control in Nonsmoking Adolescents

INTRODUCTION

Despite its well-established negative effects, environmental tobacco smoke (ETS) exposure remains highly prevalent worldwide. ETS exposure is associated with a wide range of physical and mental health-related problems among youth, including an increased likelihood to develop nicotine dependence. Up till now, neurocognitive effects of ETS exposure are largely unknown, while such effects could explain the role of ETS exposure in the development of nicotine dependence. Therefore, this preregistered study investigated the role of current ETS exposure in brain functioning associated with smoking cue-reactivity and inhibitory control.

METHOD

Concurrent with functional magnetic resonance imaging, nonsmoking adolescents aged 14-18 years (N = 51) performed a smoking cue-reactivity task, assessing brain functioning to smoking cues, and a Go/NoGo task measuring inhibitory control. ETS exposure was measured using a self-report questionnaire and biochemically verified.

RESULTS

No significant associations were observed between current ETS exposure and brain functioning associated with smoking cue-reactivity and inhibitory control.

CONCLUSION

These findings suggest that low-to-moderate levels of current ETS exposure are not associated with increased salience of smoking cues or deficits in inhibitory control in nonsmoking adolescents. Longitudinal research is needed to further clarify the exact effect of lifetime ETS exposure on brain functioning, as well as research focusing on the effects of higher levels of ETS exposure.

Molecular and neuronal mechanisms underlying the effects of adolescent nicotine exposure on anxiety and mood disorders

Tobacco addiction is highly co-morbid with a variety of mental health conditions, including schizophrenia, mood and anxiety disorders. Nicotine, the primary psychoactive compound in tobacco-related products is known to functionally modulate brain circuits that are disturbed in these disorders. Nicotine can potently regulate the transmission of various neurochemicals, including dopamine (DA), γ-amino-butyric acid (GABA) and glutamate, within various mesocorticolimbic structures, such as the ventral tegmental area (VTA), nucleus accumbens (NAc) and prefrontal cortex (PFC), all of which show pathologies in these disorders. Many neuropsychiatric diseases have etiological origins during neurodevelopment, typically occurring during vulnerable periods of adolescent or pre-natal brain development. During these neurodevelopmental periods, exposure to extrinsic drug insults can induce enduring and long-term pathophysiological sequelae that ultimately increase the risk of developing chronic mental health disorders in later life. These vulnerability factors are of growing concern given rising rates of adolescent nicotine exposure via traditional tobacco use and the increasing use of alternative nicotine delivery formats such as vaping and e-cigarettes. A large body of clinical and pre-clinical evidence points to an important role for adolescent exposure to nicotine and increased vulnerability to developing mood and anxiety disorders in later life. This review will examine current clinical and pre-clinical evidence that pinpoints specific mechanisms within the mesocorticolimbic circuitry and molecular biomarkers linked to the association between adolescent nicotine exposure and increased risk of developing mood and anxiety-related disorders. This article is part of the special issue on 'Vulnerabilities to Substance Abuse'.

Adolescent Substance Use and the Brain: Behavioral, Cognitive and Neuroimaging Correlates

Adolescence is an important ontogenetic period that is characterized by behaviors such as enhanced novelty-seeking, impulsivity, and reward preference, which can give rise to an increased risk for substance use. While substance use rates in adolescence are generally on a decline, the current rates combined with emerging trends, such as increases in e-cigarette use, remain a significant public health concern. In this review, we focus on the neurobiological divergences associated with adolescent substance use, derived from a cross-sectional, retrospective, and longitudinal studies, and highlight how the use of these substances during adolescence may relate to behavioral and neuroimaging-based outcomes. Identifying and understanding the associations between adolescent substance use and changes in cognition, mental health, and future substance use risk may assist our understanding of the consequences of drug exposure during this critical window.

A temporal chronnectomic framework: Cigarette smoking preserved the prefrontal dysfunction in schizophrenia

The widespread cigarette smoking behavior in schizophrenia is generally attributed to its alleviation of patients' symptomatology by the self-medication hypothesis. The prefrontal cortex (PFC), which predominantly supports orchestrating thoughts and actions, might underlie the biological underpinnings of smoking behavior in schizophrenia. However, few studies have focused on the impact of smoking on the prefrontal function in schizophrenia. This study assumed that smoking-related alterations on the prefrontal dynamics of information integration (chronnectome) were different between healthy control (HC) and schizophrenia patient (SP). We recruited SP smokers (N = 22)/nonsmokers (N = 27) and HC smokers (N = 22)/nonsmokers (N = 21) who underwent resting-state functional magnetic resonance imaging (rsfMRI) with a total of 240 volumes (lasting for 480 s). We employed a chronnectomic density analysis on the rsfMRI signal by using a sliding-window method. We examined the interaction effect between smoking status and diagnosis utilizing two-way analysis of covariance under permutation test. Whereas disease-related reduced effects were found on the bilateral dorsolateral PFC chronnectomic density, no smoking effect was observed. As regards interaction effect, a smoking-related reduced effect was found on the right dorsolateral PFC chronnectomic density in HC, while a smoking-related increased effect was observed in SP. Nevertheless, post-hoc analysis revealed significant group difference between SP smokers and HC nonsmokers. Therefore, these results indicated a smoking-related preservation effect on disrupted prefrontal dynamics in schizophrenia that cannot restore it to normal levels. The novel findings yield a prefrontal-based chronnectome framework to elaborate upon the self-medication hypothesis in schizophrenia.

Multimodal Neuroimaging Differences in Nicotine Abstinent Smokers Versus Satiated Smokers

INTRODUCTION

Research on cigarette smokers suggests cognitive and behavioral impairments. However, much remains unclear how the functional neurobiology of smokers is influenced by nicotine state. Therefore, we sought to determine which state, be it acute nicotine abstinence or satiety, would yield the most robust differences compared with nonsmokers when assessing neurobiological markers of nicotine dependence.

METHODS

Smokers (N = 15) and sociodemographically matched nonsmokers (N = 15) were scanned twice using a repeated-measures design. Smokers were scanned after a 24-hour nicotine abstinence and immediately after smoking their usual brand cigarette. The neuroimaging battery included a stop-signal task of response inhibition and pseudocontinuous arterial spin labeling to measure cerebral blood flow (CBF). Whole-brain voxel-wise analyses of covariance were carried out on stop success and stop fail Stop-Signal Task contrasts and CBF maps to assess differences among nonsmokers, abstinent smokers, and satiated smokers. Cluster correction was performed using AFNI's 3dClustSim to achieve a significance of p < .05.

RESULTS

Smokers exhibited higher brain activation in bilateral inferior frontal gyrus, a brain region known to be involved in inhibitory control, during successful response inhibitions relative to nonsmokers. This effect was significantly higher during nicotine abstinence relative to satiety. Smokers also exhibited lower CBF in the bilateral inferior frontal gyrus than nonsmokers. These hypoperfusions were not different between abstinence and satiety.

CONCLUSIONS

These findings converge on alterations in smokers in prefrontal circuits known to be critical for inhibitory control. These effects are present, even when smokers are satiated, but the neural activity required to achieve performance equal to controls is increased when smokers are in acute abstinence.

IMPLICATIONS

Our multimodal neuroimaging study gives neurobiological insights into the cognitive demands of maintaining abstinence and suggests targets for assessing the efficacy of therapeutic interventions.

12 h Abstinence-Induced ERP Changes in Young Smokers: Electrophysiological Evidence From a Go/NoGo Study

Decreased inhibition control ability and increased craving may be the most important causes of relapsing in smoking. Although inhibition control defects in young smokers were investigated, the effects of short-term abstinence on inhibition control in young smokers were still unclear. Thirty young smokers participated in the present study. The EEG signals during the Go/NoGo task were recorded in both satiety and 12 h abstinence conditions. The task performances were observed and compared between the two conditions. Event-related potential (ERP) analysis was used to investigate changes in N200 and P300 amplitude and latency induced by 12 h of abstinence. After 12 h of abstinence, the latency of N200 was prolonged in young smokers. No significant changes were found in the number of NoGo errors and the response time of Go in young smokers after 12 h of abstinence. Correlation analysis showed that the N200 latency of abstinence condition was significantly correlated with the number of NoGo errors and the response time of Go in the abstinence condition. The present findings may improve the understanding of the effect of short-term abstinence in young smokers. We suggested that the latency of N200 may be associated with inefficient inhibitory control of the abstinence condition in young smokers. Our results may contribute new insights into the neural mechanism of nicotine abstinence in young smokers.

Temporal dynamic changes of intrinsic brain activity in schizophrenia with cigarette smoking

Mounting evidence from multimodal neuroimaging studies has supported a neurobiological basis for schizophrenia-nicotine dependence comorbidity. However, this evidence comes exclusively from studies measuring static intrinsic activity/connectivity of the brain, while the dynamic effects of this comorbidity remain poorly understood. The current study therefore sought to examine whether temporal dynamic intrinsic brain activity interacted with diagnosis (schizophrenics vs. healthy controls) and smoking status (smokers vs. non-smokers). We used a mixed sample design and included the following four groups: i) schizophrenic smokers (n = 22), ii) schizophrenic non-smokers (n = 27), iii) healthy control smokers (n = 22), and iv) healthy control non-smokers (n = 21). All subjects underwent functional magnetic resonance imaging during the resting state. The temporal variability in intrinsic brain activity among the four groups was compared using a novel dynamic amplitude of low-frequency fluctuation (dALFF) method. A significant main effect of diagnosis was found in the left superior parietal gyrus (SPG; F_{(1, 88)} = 142.1, P < 0.0001). Moreover, the dALFF strength in the SPG was positively correlated with disease duration in patients with schizophrenia (Rho₍₄₆₎ = 0.43, P = 0.002). In addition, a significant interaction between diagnosis and smoking status was observed in the left dorsolateral prefrontal cortex (DLPFC; F_{(1, 88)} = 7.39, P = 0.008), which was consistent with the self-medication hypothesis. Together, this study has demonstrated for the first time that nicotine restores dynamic intrinsic brain activity in the left DLPFC in patients with schizophrenia. This interaction may be a clinical neuromarker for increased comorbid smoking in schizophrenia.

Meta-analysis of aberrant post-error slowing in substance use disorder: implications for behavioral adaptation and self-control

Individual with substance use disorders have well-recognized impairments in cognitive control, including in behavioral adaptation after mistakes. One way in which this impairment manifests is via diminished post-error slowing, the increase in reaction time following a task-related error that is posited to reflect cautionary or corrective behavior. Yet, in the substance use disorder literature, findings with regard to post-error slowing have been inconsistent, and thus could benefit from quantitative integration. Here, we conducted a meta-analysis of case-control studies examining post-error slowing in addiction. Twelve studies with 15 unique comparisons were identified, comprising 567 substance users and 384 healthy controls across three broad types of inhibitory control paradigms (go-no/go, conflict resolution, and stop signal tasks, respectively). Results of the random-effects meta-analysis revealed a moderate group difference across all studies (Cohen's d = 0.31), such that the individuals with substance use disorder had diminished post-error slowing compared with controls. Despite this omnibus effect, there was also large variability in the magnitude of the effects, explained in part by differences between studies in task complexity. These findings suggest that post-error slowing may serve as a promising and easy-to-implement measure of cognitive control impairment in substance use disorder, with potential links to aberrant brain function in cognitive control areas such as the anterior cingulate cortex.

The relationship between nicotine and psychosis

Cigarette smoking is strongly associated with psychotic disorders such as schizophrenia. For several decades it was assumed that the relationship could be explained by reverse causation; that smoking was secondary to the illness itself, either through self-medication or a process of institutionalization, or was entirely explained by confounding by cannabis use or social factors. However, studies have exposed that such hypotheses cannot fully explain the association, and more recently a bidirectional relationship has been proposed wherein cigarette smoking may be causally related to risk of psychosis, possibly via a shared genetic liability to smoking and psychosis. We review the evidence for these candidate explanations, using findings from the latest epidemiological, neuroimaging, genetic and preclinical work.

Emotion dysregulation and body mass index: The explanatory role of emotional eating among adult smokers

There is limited understanding of the relationship between emotion dysregulation and weight gain among smokers, although available data suggest there are potential relationships that may be of clinical importance. The present study explored a potential mechanism in the relationship between emotion dysregulation and body mass index (BMI). Specifically, the current study examined the indirect effects of emotional eating on the association between emotion dysregulation and BMI among smokers. Participants included 136 (52.2% female; M_age = 42.25, SD = 11.24) adults who were treatment-seeking smokers. Primary analysis included one regression-based model, wherein emotion dysregulation served as the predictor, emotional eating as the intermediary variable, and BMI as the criterion variable. Covariates were age and gender. Results indicated that emotional dysregulation was significantly associated with BMI through emotional eating (a*b = 0.02, SE = 0.01, CI_95% = 0.002, 0.042). The current findings provide initial empirical evidence that greater reported levels of emotion dysregulation may be associated with greater reported levels of emotional eating, which in turn, may be related to higher BMI.

Brain Function Network and Young Adult Smokers: A Graph Theory Analysis Study

Cigarette smoking is associated with abnormalities in the widespread inter-regional functional connectivity of the brain. However, few studies focused on the abnormalities in the topological organization of brain functional networks in young smokers. In the current study, resting-state functional magnetic resonance images were acquired from 30 young male smokers and 32 age-, gender-, and education-matched healthy male nonsmokers. A functional network was constructed by calculating the Pearson correlation coefficients among 246 subregions in the human Brainnetome Atlas. The topological parameters were compared between smokers and nonsmokers. The results showed that the functional network of both young smokers and nonsmokers had small-world topology. Compared to nonsmokers, young smokers exhibited a decreased clustering coefficient (C_p) and local network efficiency (E_local). C_p and E_local were negatively correlated with the duration of cigarette use. In addition, increased nodal efficiency (E_nodal) was mainly located in the prefrontal cortex (PFC), cingulate gyrus, insula, and caudate. Decreased connectivities among the PFC, cingulate gyrus, insula, basal ganglia (of specific node), and thalamus were also observed. In sum, we revealed the abnormal topological organization of brain functional networks in young smokers, which may improve our understanding of the neural mechanism of young smokers from a brain functional network topological organization perspective.

Striato-cortical tracts predict 12-h abstinence-induced lapse in smokers

Striatal circuit dysfunction is implicated in smoking behaviors and lapses during abstinence attempts. However, little is known about whether the structural connectivity of striatal tracts can be used to predict abstinence-induced craving and lapses. The tract strengths of striatal circuits were compared in 53 male nicotine-dependent cigarette smokers and 58 matched nonsmokers, using seed-based classification by diffusion tensor imaging (DTI) probabilistic tractography with 10 a priori target masks. A 12-h abstinence procedure was then employed, after which 31 individuals abstained and 22 lapsed. Linear regression and binary logistic regression was conducted to test whether the tract strength of frontostriatal circuits was associated with craving changes in abstainers and predicted lapse in smokers. Compared with nonsmokers, in the left hemisphere, smokers showed weaker tract strength in striatum-medial orbitofrontal cortex (mOFC), striatum-ventral lateral prefrontal cortex (vlPFC), striatum-inferior frontal gyrus (IFG) and striatum-posterior cingulate cortex (PCC) (Bonferroni corrected, p < 0.05/20 = 0.0025). In abstainers, the abstinence-induced increases in craving were associated with the tract strength of the left striatum-mOFC and striatum-vlPFC. The tract strength of left striatum-dorsolateral PFC (dlPFC) predicted lapse in smokers with an accuracy of 68.3%. These results provide system-level insights into the weaker tract strength of frontostriatal circuits in male smokers and their potential roles as neuroimaging markers for abstinence-induced craving and risk of lapse. Future studies in female smokers are needed to determine if this generalizes across genders.

Early life adversity and health-risk behaviors: proposed psychological and neural mechanisms

Early life adversity (ELA) is associated with poorer health in adulthood, an association explained, at least in part, by increased engagement in health-risk behaviors (HRBs). In this review, we make the case that ELA influences brain development in ways that increase the likelihood of engaging in HRBs. We argue that ELA alters neural circuitry underpinning cognitive control as well as emotional processing, including networks involved in processing threat and reward. These neural changes are associated psychologically and behaviorally with heightened emotional reactivity, blunted reward responsivity, poorer emotion regulation, and greater delay discounting. We then demonstrate that these adaptations to ELA are associated with an increased risk of smoking cigarettes, drinking alcohol, and eating high-fat, high-sugar foods. Furthermore, we explore how HRBs affect the brain in ways that reinforce addiction and further explain clustering of HRBs.

Differential Activation of the Left and Right Cerebral Hemispheres of Individuals Who Use or are Dependent on Drugs of Abuse

Introduction:

The left and right cerebral hemispheres are not equivalent in performance of cognitive functions associated with risk factors of drug abuse, nor is their development equivalently affected by drugs of abuse. The question addressed here is whether drugs of abuse affect cognitive function as assessed by brain activation, in particular related to impulsivity, and/or whether weaker brain activation associated with impulsivity increases the risk of drug abuse.

Methodology:

Using PubMed and key words, articles were selected that addressed brain activation in individuals who used or abused one of the psychoactive drugs. Findings are summarized.

Results:

For each of the drugs, hypoactivation was found. In some cases this reduced activation was reported predominantly for the right or both hemispheres. There were fewer reports for the left hemisphere.

Discussion and Conclusion:

Rarely do authors focus on why only one or the other hemisphere is affected or why specific structures are affected. Neurobiological differences between the hemispheres and among various brain structures could provide clues to the specific effect of drugs. Increased attention to this gap in research will give additional insights into the etiology of drug abuse and provide direction for treatment.

Prediction of the Effect of Sleep Deprivation on Response Inhibition via Machine Learning on Structural Magnetic Resonance Imaging Data

Sleep deprivation (SD) impairs the ability of response inhibition. However, few studies have explored the quantitative prediction of performance impairment using Magnetic Resonance Imaging (MRI) data. In this study, structural MRI data were used to predict the change in response inhibition performance (ΔSSRT) measured by a stop-signal task (SST) after 24 h of SD in 52 normal young subjects. For each subject, T1-weighted MRI data were acquired and the gray matter (GM) volumes were calculated using voxel-based morphometry (VBM) analysis. First, the regions in which GM volumes correlated with ΔSSRT were explored. Then, features were extracted from these regions and the prediction process was performed using a linear regression model with four-fold cross-validation. We found that the GM volumes of the left middle frontal gyrus (L_MFG), pars opercularis of right inferior frontal gyrus (R_IFG), pars triangularis of left inferior frontal gyrus, pars opercularis of right rolandic area, left supplementary motor area (L_SMA), left hippocampus, right lingual gyrus, right postcentral gyrus and left middle temporal gyrus (L_MTG) could predict the ΔSSRT with a low mean square error of 0.0039 ± 0.0011 and a high Pearson’s correlation coefficient between the predicted and actual values of 0.948 ± 0.0503. In conclusion, our results demonstrated that a linear combination of structural MRI data could accurately predict the change in response inhibition performance after SD. Further studies with larger sample sizes and more comprehensive sample may be necessary to validate these findings.

Central Neural Correlates During Inhibitory Control in Lifelong Premature Ejaculation Patients

Lifelong premature ejaculation (LPE) is a common male sexual dysfunction. Lack of active control for rapid ejaculation brought great distress to sexual harmony and even fertility. Previous neurophysiology studies revealed an ejaculation-related control mechanism in the brain. However, it remains unclear whether this inhibitory network is altered in LPE patients. The present study investigated the central inhibitory network function of LPE patients by using stop signal task (SST)-related functional magnetic resonance imaging (fMRI) and resting-state functional connectivity (FC) analysis. The results showed no difference in task-related behavioral performance or neural activation during response inhibition between LPE patients and controls. However, LPE patients showed a significantly different correlation pattern between the stop signal reaction time (SSRT) and left inferior frontal gyrus (IFG) activation during successful inhibition, in which a typical negative correlation between SSRT and the activation was completely disappeared in patients. In addition, using the left IFG as a seed, patients showed weaker FC between the seed and two areas (left dentate nucleus (DN) and right frontal pole) compared with controls. These data suggest that LPE patients have an abnormal brain control network, which may contribute to the reduced central control of rapid ejaculation. This study provides new insights into the neural mechanism of LPE involving the central inhibitory network, which may offer an underlying intervention target for future treatment.

Positive and Negative Affect and Adolescent Adjustment: Moderation Effects of Prefrontal Functioning

We examined whether cognitive control moderates the effects of emotion on adolescent internalizing and externalizing symptomatology in a longitudinal study of 138 adolescents. Self-reported positive affect (PA) and negative affect and behavioral and neural indicators of cognitive control, indexed by performance and prefrontal hemodynamic response during a cognitive interference task, were collected at Time 1. Self-reported internalizing and externalizing symptomatology were collected at Time 1 and Time 2 (1 year later). Results indicated that higher PA predicted decreases in externalizing symptomatology, but only for adolescents with poor neural cognitive control. No moderation effects were found for behavioral cognitive control. Findings imply the beneficial effects of PA on the development of externalizing problems among adolescents with poor prefrontal functioning.

Anterior insula activation during inhibition to smoking cues is associated with ability to maintain tobacco abstinence

Relapse to smoking after initial abstinence is a major clinical challenge with significant public health consequences. At the brain and behavioral level, those who relapse to tobacco smoking have both greater cue-reactivity and lower inhibitory control than those who remain abstinent. Little is known about neural activation during inhibitory control tasks in the presence of drug-related cues. In the current study, tobacco smokers (SMK; n = 22) and non-smoking controls (CON; n = 19) completed a Go/NoGo task involving smoking cues during a functional magnetic resonance imaging (fMRI) scan. Following the scan session, smokers were required to quit smoking, and maintenance of abstinence was evaluated as part of a 12-week smoking cessation trial. We evaluated pre-cessation brain activity during NoGo trials in smokers who were versus were not able to quit smoking. We then compared fMRI and inhibitory control measures between smokers and non-smokers. We did not find differences between SMK and CON in performance or activation to smoking or neutral cues. However, compared to SMK who relapsed, SMK who attained biochemically-validated abstinence at the end of the smoking cessation trial had greater neural activation in the anterior insula during NoGo trials specifically with smoking-related cues. Results indicate that within SMK, decreased inhibitory control activation during direct exposure to drug-related stimuli may be a marker of difficulty quitting and relapse vulnerability.

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Smokers and controls showed no differences in performance or activation to smoking or neutral cues.

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Abstinent smokers compared to relapsers had greater activation in the insula during NoGo trials with smoking-related cues.

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Within smokers, decreased NoGo activation during exposure to drug-related cues may be a marker of relapse vulnerability.

Perceptions of the Harm and Addictiveness of Conventional Cigarette Smoking Among Adolescent E-Cigarette Users

PURPOSE

Although existing evidence indicates that e-cigarette use is a risk factor for cigarette smoking initiation, mechanisms of this association are not yet known. E-cigarette users perceive e-cigarette use to be less harmful relative to conventional cigarettes, but their absolute perceptions of addictiveness of conventional cigarette smoking are unknown. This study examines how e-cigarette users compare with nonusers (non-e-cigarette users/nonconventional cigarette smokers), conventional cigarette smokers, and dual users on perceptions of harm and the addictiveness of conventional cigarette smoking and on other known predictors of cigarette smoking such as peer smoking, influence of antismoking ads, and risk-taking propensity.

METHODS

National samples of 8th- and 10th-grade students from 2014 and 2015 (N = 14,151) were obtained from the Monitoring the Future Study. Multivariate logistic regression models were used to examine relationships between adolescent smoking status and perceptions of harm and the addictiveness of conventional cigarette smoking while controlling for potential confounders.

RESULTS

E-cigarette users had lower perceptions of the addictiveness of conventional cigarette smoking compared with nonusers but higher than cigarette smokers and dual users. E-cigarette users reported lower influence by antismoking ads, more conventional cigarette-smoking peers, and greater risk-taking propensity than nonusers. E-cigarette users and cigarette smokers did not differ in their perceived harm of conventional cigarette smoking or in their risk-taking propensity.

CONCLUSIONS

E-cigarette users' attitudes and perceptions regarding conventional cigarette smoking may leave them vulnerable to becoming conventional cigarette smokers. Future studies should explore the prospective relationship between smoking-related perceptions of conventional cigarette smoking among e-cigarette users and the onset of cigarette smoking.

The extended evolutionary synthesis and addiction: the price we pay for adaptability

Humans are more likely to become addicted and to stay addicted than are other animals. This chapter is a neurobiological and molecular review of addiction and the cooccurring traits and psychiatric disorders from the perspective of the Extended Evolutionary Synthesis (EES). Addiction is an example of pleiotropy as many common haplotypes that are associated with individual differences in vulnerability to substance dependence express a variety of important brain-based phenotypes such as neuroadaptive processes. The neurochemical mechanisms of addiction are shared with behavioral flexibility and the ability to innovate, which are hallmark features of our species. The dopaminergic system provides a link between addiction and the cooccurring traits and psychiatric disorders evident in the shared genetic profile. A hypofunctioning dopaminergic system is also a common characteristic feature of addiction and the cooccurring traits and psychiatric disorders. Epigenetics allows for environmental factors to create lasting and heritable phenotypic changes enabling rapid adaptation to an environment. Addiction "high-jacks" this system as well as the neurochemical mechanisms that control flexibility and innovation and is, thus, the price we pay for adaptability.

Cognitive avoidance and aversive cues related to tobacco in male smokers

BACKGROUND

Treatment using aversive conditioning has been suggested for smoking cessation. The efficacy of this method is thought to be associated with cognitive avoidance. We compare differences in avoidance traits and patterns of associated brain activation in response to cues that induce cravings versus aversion between smokers and non-smokers.

METHODS

Fifteen smokers and fifteen non-smokers completed cue reactivity tasks while undergoing functional magnetic resonance imaging (fMRI) to examine brain responses to craving-inducing cues (Cr) and aversion-inducing cues (Av). Participant avoidant traits were also assessed.

RESULTS

Activation of the left frontal subcallosal gyrus in response to Cr was greater in smokers than in non-smokers. Smokers showed less activation in the right temporal lobe in response to Av than did non-smokers. Brain activation in response to Cr in the left frontal subcallosal gyrus was positively correlated with Fagerstrom Test for Nicotine Dependence (FTND) scores in smokers. Brain activation in response to Av in the right temporal lobe was negatively correlated with the Korean Version of the Cognitive Avoidance Questionnaire (KCAQ) scores in non-smokers.

CONCLUSIONS

Cognitive avoidance in smokers during aversive stimulation might result in sustaining addictive behaviors. On the other hand, non-smokers may be able to emotionally confront the adverse effects of smoking.

Intra-regional and inter-regional abnormalities and cognitive control deficits in young adult smokers

Tobacco use during later adolescence and young adulthood may cause serious neurophysiological changes; rationally, it is extremely important to study the relationship between brain dysfunction and behavioral performances in young adult smokers. Previous resting state studies investigated the neural mechanisms in smokers. Unfortunately, few studies focused on spontaneous activity differences between young adult smokers and nonsmokers from both intra-regional and inter-regional levels, less is known about the association between resting state abnormalities and behavioral deficits. Therefore, we used fractional amplitude of low frequency fluctuation (fALFF) and resting state functional connectivity (RSFC) to investigate the resting state spontaneous activity differences between young adult smokers and nonsmokers. A correlation analysis was carried out to assess the relationship between neuroimaging findings and clinical information (pack-years, cigarette dependence, age of onset and craving score) as well as cognitive control deficits measured by the Stroop task. Consistent with previous addiction findings, our results revealed the resting state abnormalities within frontostriatal circuits, i.e., enhanced spontaneous activity of the caudate and reduced functional strength between the caudate and anterior cingulate cortex (ACC) in young adult smokers. Moreover, the fALFF values of the caudate were correlated with craving and RSFC strength between the caudate and ACC was associated with the cognitive control impairments in young adult smokers. Our findings could lead to a better understanding of intrinsic functional architecture of baseline brain activity in young smokers by providing regional and brain circuit spontaneous neuronal activity properties as well as their association with cognitive control impairments.

The neural mechanism underpinning balance calibration between action inhibition and activation initiated by reward motivation

In everyday life, it is often the case that in some situations we are motivated and want not only to speed up our actions but also to avoid mistakes—for example, ballgames. How our brain works at that moment to resolve the situations and react properly has created an active research field. Previous findings indicated that maintaining a balance between withholding and executing an action are highly dynamic and involve many executive control processes. This fMRI study was set up to investigate how motivation affects these balancing processes. With manipulation of prospective rewards in a stop-signal task where both the proactive and reactive control were equally emphasized, our behavioral results replicated previous findings. The fMRI findings backed up the behavioral results. We found motivation effects in the anterior caudate and pre-SMA for action inhibition. The former works to register motivation status, the latter works to transform motivation into action inhibition control. Together with the results of connectivity analysis, our study also suggests a hierarchical relationship between functional roles of pre-SMA and right inferior frontal gyrus during action inhibition. While the pre-SMA acts to accommodate higher-order factors, such as motivation, for action control, the right inferior frontal cortex acts to participate in the execution of action inhibition. This study pinned down a neural mechanism that integrates reward motivation into action inhibition control.

Neural Correlates of Response Inhibition in Adolescents Prospectively Predict Regular Tobacco Smoking

Inhibitory deficits have been widely reported in addiction; however, it remains unclear whether such deficits represent a determinant or a consequence of substance use. Here we show, using a prospective longitudinal design, that developmental abnormalities in the neural correlates of response inhibition in adolescents increase the risk for subsequent cigarette smoking. Reduced No-Go P3 amplitude, delayed latency of Go P3 peak, and reduced synchrony of neuronal oscillations at age 14 prospectively predicted regular smoking at age 18. The present findings suggest that functional brain correlates of response inhibition represent a developmental marker of risk for future substance abuse.

Reward-related frontostriatal activity and smoking behavior among adolescents in treatment for smoking cessation

BACKGROUND

Tobacco use is often initiated during adolescence and continued into adulthood despite desires to quit. A better understanding of the neural correlates of abstinence from smoking in adolescents may inform more effective smoking cessation interventions. Neural reward systems are implicated in tobacco use disorder, and adolescent smokers have shown reduced reward-related ventral striatal activation related to increased smoking.

METHODS

The current study evaluated nondrug reward anticipation in adolescent smokers using a monetary incentive delay task in fMRI pre- and post- smoking cessation treatment (n=14). This study tested how changes in neural responses to reward anticipation pre- to post-treatment were related to reduced smoking. An exploratory analysis in a larger sample of adolescents with only pre-treatment fMRI (n=28) evaluated how neural responses to reward anticipation were related to behavioral inhibition and behavioral activation scales.

RESULTS

Adolescent smokers showed pre- to post-treatment increases in reward anticipation-related activity in the bilateral nucleus accumbens and insula, and medial prefrontal cortex, and greater increases in reward anticipation-related activity were correlated with larger percent days of smoking abstinence during treatment.

CONCLUSIONS

These findings suggest that reduced smoking during smoking cessation treatment is associated with a "recovery of function" in frontostriatal responses to nondrug reward anticipation in adolescent smokers, although comparison with a developmental control group of adolescent nonsmokers is warranted.

Age and impulsive behavior in drug addiction: A review of past research and future directions

Impulsive behavior is implicated in the initiation, maintenance, and relapse of drug-seeking behaviors involved in drug addiction. Research shows that changes in impulsive behavior across the lifespan contribute to drug use and addiction. The goal of this review is to examine existing research on the relationship between impulsive behavior and drug use across the lifespan and to recommend directions for future research. Three domains of impulsive behavior are explored in this review: impulsive behavior-related personality traits, delay discounting, and prepotent response inhibition. First, we present previous research on these three domains of impulsive behavior and drug use across developmental stages. Then, we discuss how changes in impulsive behavior across the lifespan are implicated in the progression of drug use and addiction. Finally, we discuss the relatively limited attention given to middle-to-older adults in the current literature, consider the validity of the measures used to assess impulsive behavior in middle-to-older adulthood, and suggest recommendations for future research.

Executive functioning and substance use in adolescence: Neurobiological and behavioral perspectives

The current review is guided by the theoretical perspective that emphasizes the regulating role of executive functioning (Carver et al., 2009) and presents studies that elucidate the ways that executive functioning (inhibition and working memory) explain individual differences in adolescent substance use independently or by regulating the reactive system (reward and punishment sensitivity). Behavioral studies indicate that main effects of executive functioning on adolescent substance use are often nonsignificant or weak in effect sizes. In contrast, emerging evidence suggests consistent and stronger regulating effects of executive functioning over reward and punishment sensitivity. Functional neuroimaging studies reveal significant associations between executive functioning task-related hemodynamic responses and substance use with strong effect sizes. There is also direct evidence from studies testing statistical interactions of the regulating effects of EF-related brain activation, and indirect evidence in studies examining functional connectivity, temporal discounting, and reinforced control. We note key future directions and ways to address limitations in existing work.

Developmental toxicity of nicotine: A transdisciplinary synthesis and implications for emerging tobacco products

While the health risks associated with adult cigarette smoking have been well described, effects of nicotine exposure during periods of developmental vulnerability are often overlooked. Using MEDLINE and PubMed literature searches, books, reports and expert opinion, a transdisciplinary group of scientists reviewed human and animal research on the health effects of exposure to nicotine during pregnancy and adolescence. A synthesis of this research supports that nicotine contributes critically to adverse effects of gestational tobacco exposure, including reduced pulmonary function, auditory processing defects, impaired infant cardiorespiratory function, and may contribute to cognitive and behavioral deficits in later life. Nicotine exposure during adolescence is associated with deficits in working memory, attention, and auditory processing, as well as increased impulsivity and anxiety. Finally, recent animal studies suggest that nicotine has a priming effect that increases addiction liability for other drugs. The evidence that nicotine adversely affects fetal and adolescent development is sufficient to warrant public health measures to protect pregnant women, children, and adolescents from nicotine exposure.

Intra-individual changes in Stroop-related activations linked to cigarette abstinence in adolescent tobacco smokers: Preliminary findings

BACKGROUND

Adolescence is a crucial time for initiation of tobacco-smoking. Developing more effective treatment interventions for tobacco-smoking in youth is therefore critical to reduce smoking rates in both adolescent and adult populations. Elucidation of the neural mechanisms of successful behavioral change (abstinence) will allow for improvement of therapies based on known brain mechanisms.

METHODS

Twenty-one adolescent tobacco-smokers (14-19 years) participated in functional magnetic resonance imaging (fMRI) during performance of a cognitive control (Stroop) task prior to randomization to smoking cessation treatment (trial of combined nicotine replacement therapy/placebo and contingency management for attendance/abstinence; NCT01145001). Fourteen adolescents also participated in fMRI scanning following completion of the six-week trial. fMRI data were analyzed using random-effects models in SPM12. Paired t-tests were used to identify group-level changes (main effect of treatment exposure) in neural functional responses. Regression models were used to identify individual-level changes associated with treatment-outcomes (percent days abstinent, maximum days of consecutive abstinence).

RESULTS

Main effects of Stroop task performance (contrast of incongruent versus congruent trials) were seen across a priori ROIs at both pre- and post-treatment (pFWE<0.05). At the group-level, no changes in neural responses were found following treatment. However, intra-individual reductions in Stroop-related activity (within the insula and anterior cingulate) were positively associated with measures of smoking abstinence during treatment (pFWE<0.05).

CONCLUSIONS

Abstinence from tobacco during smoking cessation treatment among adolescents is associated with cognitive-control related reductions in neural activity within specific regions (anterior cingulate, insula), suggesting that increases in cognitive efficiency may underlie optimal treatment responses in this population.

Etiological theories of addiction: A comprehensive update on neurobiological, genetic and behavioural vulnerability

Currently, about 246 million people around the world have used an illicit drug. The reasons for this use are multiple: e.g. to augment the sensation of pleasure or to reduce the withdrawal and other aversive effects of a given substance. This raises the problem of addiction, which remains a disease of modern society. This review offers a comprehensive update of the different theories about the etiology of addictive behaviors with emphasis on the neurobiological, environmental, psychopathological, behavioural and genetic aspects of addictions, discussed from an evolutionary perspective. The main conclusion of this review is that vulnerability to drug addiction suggests an interaction between many brain systems (including the reward, decision-making, serotonergic, oxytocin, interoceptive insula, CRF, norepinephrine, dynorphin/KOR, orexin and vasopressin systems), genetic predisposition, sociocultural context, impulsivity and drugs types. Further advances in biological and psychological science are needed to address the problems of addiction at its roots.

Interventions for prevention and treatment of tobacco smoking in school-aged children and adolescents: A systematic review and meta-analysis

OBJECTIVES

To determine the effectiveness of primary health care relevant interventions to prevent and treat tobacco smoking in school-aged children and adolescents.

METHODS

This systematic review considered studies included in a prior review. We adapted and updated the search to April 2015. Titles, abstracts and full-text articles were reviewed in duplicate; data extraction and quality assessments were performed by one reviewer and verified by another. Meta-analyses and pre-specified sub-group analyses were performed when possible. PROSPERO #CRD42015019051.

RESULTS

After screening 2118 records, we included nine randomized controlled trials. The mostly moderate quality evidence suggested targeted behavioral interventions can prevent smoking and assist with cessation. Meta-analysis showed intervention participants were 18% less likely to report having initiated smoking at the end of intervention relative to controls (Risk Ratio 0.82; 95% confidence interval 0.72, 0.94); the absolute effect is 1.92% for smoking initiation, Number Needed to Treat is 52 (95% confidence interval 33, 161). For cessation, meta-analysis showed intervention participants were 34% more likely to report having quit smoking at the end of intervention relative to controls (Risk Ratio 1.34; 95% confidence interval 1.05, 1.69); the absolute effect is 7.98% for cessation, Number Needed to Treat is 13 (95% confidence interval 6, 77). Treatment harms were not mentioned in the literature and no data were available to assess long-term effectiveness.

CONCLUSION

Primary care relevant behavioral interventions improve smoking outcomes for children and youth. The evidence on key components is limited by heterogeneity in methodology and intervention strategy. Future trials should target tailored prevention or treatment approaches, establish uniform definition and measurement of smoking, isolate optimal intervention components, and include long-term follow-up.

Annual Research Review: On the developmental neuropsychology of substance use disorders

BACKGROUND

Adolescence represents a period of development during which critical biological, as well as social and cognitive, changes occur that are necessary for the transition into adulthood. A number of researchers have suggested that the pattern of normative brain changes that occurs during this period not only predisposes adolescents to engage in risk behaviours, such as experimentation with drugs, but that they additionally make the adolescent brain more vulnerable to the direct pharmacological impact of substances of abuse. The neural circuits that we examine in this review involve cortico-basal-ganglia/limbic networks implicated in the processing of rewards, emotion regulation, and the control of behaviour, emotion and cognition.

FINDINGS AND CONCLUSIONS

We identify certain neurocognitive and personality/comorbidity-based risk factors for the onset of substance misuse during adolescence, and summarise the evidence suggesting that these risk factors may be further impacted by the direct effect of drugs on the underlying neural circuits implicated in substance misuse vulnerability.

Risk-taking and risky decision-making in Internet gaming disorder: Implications regarding online gaming in the setting of negative consequences

Individuals with Internet gaming disorder (IGD) continue gaming despite adverse consequences. However, the precise mechanism underlying this behavior remains unknown. In this study, data from 20 IGD subjects and 16 otherwise comparable healthy control subjects (HCs) were recorded and compared when they were undergoing risk-taking and risky decision-making during functional magnetic resonance imaging (fMRI). During risk-taking and as compared to HCs, IGD subjects selected more risk-disadvantageous trials and demonstrated less activation of the anterior cingulate, posterior cingulate and middle temporal gyrus. During risky decision-making and as compared to HCs, IGD subjects showed shorter response times and less activations of the inferior frontal and superior temporal gyri. Taken together, data suggest that IGD subjects show impaired executive control in selecting risk-disadvantageous choices, and they make risky decisions more hastily and with less recruitment of regions implicated in impulse control. These results suggest a possible neurobiological underpinning for why IGD subjects may exhibit poor control over their game-seeking behaviors even when encountering negative consequences and provide possible therapeutic targets for interventions in this population.