Addiction, a condition of compulsive behaviour? Neuroimaging and neuropsychological evidence of inhibitory dysregulation

Work engagement, impulsivity and, self-efficacy among Polish workers. Moderating role of impulsivity

The study proposes adding a new component to the Job Demands-Resources Theory, termed 'personal demands'. Impulsivity serves as an illustrative example of personal demands. A cross-sectional questionnaire was conducted and a total of 394 (Female = 59.6%) workers were surveyed. Standardized survey questionnaires were used in the study, i.e. The Utrecht Work Engagement Scale (UWES-9), Life Roles Self-Efficacy Scale (LRSES) and UPPS-P Impulsive Behaviour Scale. The obtained results indicate that Work Engagement correlates negatively with Impulsivity scales (lack of premeditation (r = -.22; p < .001), lack of persistence (r = -.27; p < .001), positive urgency (r = -.12; p, < .01) and negative urgency (r = -.12; p < .01)). In addition, Positive Urgency, moderates the relation between Self-efficacy and Work Engagement, in line with the theory (B = .133; SE = .067; t = 1.98; p < .05; LLCI = .0007; ULCI = 0.2643). This confirmed the fact, that impulsivity should be included in the JDR theory as a 'personal demand'.

Elucidating the molecular symphony: unweaving the transcriptional & epigenetic pathways underlying neuroplasticity in opioid dependence and withdrawal

The persistent use of opioids leads to profound changes in neuroplasticity of the brain, contributing to the emergence and persistence of addiction. However, chronic opioid use disrupts the delicate balance of the reward system in the brain, leading to neuroadaptations that underlie addiction. Chronic cocaine usage leads to synchronized alterations in gene expression, causing modifications in the Nucleus Accumbens (NAc), a vital part of the reward system of the brain. These modifications assist in the development of maladaptive behaviors that resemble addiction. Neuroplasticity in the context of addiction involves changes in synaptic connectivity, neuronal morphology, and molecular signaling pathways. Drug-evoked neuroplasticity in opioid addiction and withdrawal represents a complicated interaction between environmental, genetic, and epigenetic factors. Identifying specific transcriptional and epigenetic targets that can be modulated to restore normal neuroplasticity without disrupting essential physiological processes is a critical consideration. The discussion in this article focuses on the transcriptional aspects of drug-evoked neuroplasticity, emphasizing the role of key transcription factors, including cAMP response element-binding protein (CREB), ΔFosB, NF-kB, Myocyte-enhancing factor 2 (MEF2), Methyl-CpG binding protein 2 (MeCP2), E2F3a, and FOXO3a. These factors regulate gene expression and lead to the neuroadaptive changes observed in addiction and withdrawal. Epigenetic regulation, which involves modifying gene accessibility by controlling these structures, has been identified as a critical component of addiction development. By unraveling these complex molecular processes, this study provides valuable insights that may pave the way for future therapeutic interventions targeting the mechanisms underlying addiction and withdrawal.

A systematic review of treatment for impulsivity and compulsivity

Introduction

The aim of this study was to comprehensively review existing treatments for impulsivity and compulsivity in non-substance addictions, driven by the importance of these factors in addictive disorder development and treatment efficacy.

Methods

A systematic review carried out following PRISMA guidelines identified 14 articles from a total of 764 studies, highlighting the limited literature that is available on psychological treatments for non-substance addictions, in particular studies focusing on impulsivity and compulsivity. The studies were categorized by behavioral addiction type.

Results

For compulsive sexual behavior and problematic pornography use, cognitive-behavioral therapy (CBT) has shown significant improvements in compulsivity. In gambling disorder, interventions like cognitive bias modification and motivational interviewing combined with CBT have been effective in reducing impulsivity. Cognitive-behavioral therapy was advocated for compulsive shopping, although results varied. For problematic internet use, dialectical behavior therapy and acceptance and commitment therapy have been effective in addressing impulsivity. Despite literature supporting CBT for most behavioral addictions, the review noted that some articles indicate that dialectical behavior therapy and acceptance and commitment therapy were also effective for problematic internet use, suggesting different underlying mechanisms for this type of addiction.

Discussion

It also highlighted limitations, including the small number of studies and the lack of standardized assessment measures. Further research is needed to understand underlying mechanisms and develop tailored treatments for impulsivity and compulsivity in non-substance addictions. These findings offer new directions for research and intervention guidelines in behavioral addictions.

Neuropsychological assessment fails to predict relapse among cigarette smokers: A prospective study of neurocognitive abilities

OBJECTIVES

Understanding the factors that lead to relapse is a major challenge for the clinical support of smoking cessation. Neurocognitive abilities such as attention, executive functioning and working memory, are possible predictors of relapse and can be easily assessed in everyday clinical practice. In this prospective longitudinal study, we investigated the relationship between pre-smoking cessation neurocognitive performance and relapse at six months in a sample of patients being treated for their tobacco dependence.

METHODS

130 tobacco consumers were included in the study. They completed a comprehensive neuropsychological and clinical assessment before smoking cessation. The targeted abilities were intelligence, inhibition, shifting, working memory updating, verbal fluency and decision-making.

RESULTS

The rate of tobacco relapse at 6 months was 58%. Logistic regressions were used to assess which variables best explained relapse. None of the neuropsychological tests was a significant predictor of relapse at either 1, 3 or 6 months, either alone, or controlling for other covariates acting as significant predictors of relapse.

CONCLUSIONS

Common neuropsychological tests, even those specifically targeting executive functioning such as inhibition, are not useful predictors of the success of a smoking cessation program in a clinical setting. Other variables, such as motivation to quit smoking or the presence of comorbid depression or anxiety disorders, appear to be more useful predictors of relapse.

Static and dynamic changes of intrinsic brain local connectivity in internet gaming disorder

BACKGROUND

Studies have revealed that intrinsic neural activity varies over time. However, the temporal variability of brain local connectivity in internet gaming disorder (IGD) remains unknown. The purpose of this study was to explore the alterations of static and dynamic intrinsic brain local connectivity in IGD and whether the changes were associated with clinical characteristics of IGD.

METHODS

Resting-state functional magnetic resonance imaging (rs-fMRI) scans were performed on 36 individuals with IGD (IGDs) and 44 healthy controls (HCs) matched for age, gender and years of education. The static regional homogeneity (sReHo) and dynamic ReHo (dReHo) were calculated and compared between two groups to detect the alterations of intrinsic brain local connectivity in IGD. The Internet Addiction Test (IAT) and the Pittsburgh Sleep Quality Index (PSQI) were used to evaluate the severity of online gaming addiction and sleep quality, respectively. Pearson correlation analysis was used to evaluate the relationship between brain regions with altered sReHo and dReHo and IAT and PSQI scores. Receiver operating characteristic (ROC) curve analysis was used to reveal the potential capacity of the sReHo and dReHo metrics to distinguish IGDs from HCs.

RESULTS

Compared with HCs, IGDs showed both increased static and dynamic intrinsic local connectivity in bilateral medial superior frontal gyrus (mSFG), superior frontal gyrus (SFG), and supplementary motor area (SMA). Increased dReHo in the left putamen, pallidum, caudate nucleus and bilateral thalamus were also observed. ROC curve analysis showed that the brain regions with altered sReHo and dReHo could distinguish individuals with IGD from HCs. Moreover, the sReHo values in the left mSFG and SMA as well as dReHo values in the left SMA were positively correlated with IAT scores. The dReHo values in the left caudate nucleus were negatively correlated with PSQI scores.

CONCLUSIONS

These results showed impaired intrinsic local connectivity in frontostriatothalamic circuitry in individuals with IGD, which may provide new insights into the underlying neuropathological mechanisms of IGD. Besides, dynamic changes of intrinsic local connectivity in caudate nucleus may be a potential neurobiological marker linking IGD and sleep quality.

Using event-related potentials to characterize inhibitory control and self-monitoring across impulsive and compulsive phenotypes: a dimensional approach to OCD

OBJECTIVE

"Subsyndromal" obsessive-compulsive disorder symptoms (OCDSs) are common and cause impaired psychosocial functioning. OCDSs are better captured by dimensional models of psychopathology, as opposed to categorical diagnoses. However, such dimensional approaches require a deep understanding of the underlying neurocognitive drivers and impulsive and compulsive traits (ie, neurocognitive phenotypes) across symptoms. This study investigated inhibitory control and self-monitoring across impulsivity, compulsivity, and their interaction in individuals (n = 40) experiencing mild-moderate OCDSs.

METHODS

EEG recording concurrent with the stop-signal task was used to elicit event-related potentials (ERPs) indexing inhibitory control (ie, N2 and P3) and self-monitoring (ie, error-related negativity and correct-related negativity (CRN): negativity following erroneous or correct responses, respectively).

RESULTS

During unsuccessful stopping, individuals high in both impulsivity and compulsivity displayed enhanced N2 amplitude, indicative of conflict between the urge to respond and need to stop (F(3, 33) = 1.48, P < .05, 95% Cl [-0.01, 0.001]). Individuals high in compulsivity and low in impulsivity showed reduced P3 amplitude, consistent with impairments in monitoring failed inhibitory control (F(3, 24) = 2.033, P < .05, 95% CI [-0.002, 0.045]). Following successful stopping, high compulsivity (independent of impulsivity) was associated with lower CRN amplitude, reflecting hypo-monitoring of correct responses (F(4, 32) = 4.76, P < .05, 95% CI [0.01, 0.02]), and with greater OCDS severity (F(3, 36) = 3.32, P < .05, 95% CI [0.03, 0.19]).

CONCLUSION

The current findings provide evidence for differential, ERP-indexed inhibitory control and self-monitoring profiles across impulsive and compulsive phenotypes in OCDSs.

The Dopamine System in Mediating Alcohol Effects in Humans

Brain-imaging studies show that the development and maintenance of alcohol use disorder (AUD) is determined by a complex interaction of different neurotransmitter systems and multiple psychological factors. In this context, the dopaminergic reinforcement system appears to be of fundamental importance. We focus on the excitatory and depressant effects of acute versus chronic alcohol intake and its impact on dopaminergic neurotransmission. Furthermore, we describe alterations in dopaminergic neurotransmission as associated with symptoms of alcohol dependence. We specifically focus on neuroadaptations to chronic alcohol consumption and their effect on central processing of alcohol-associated and reward-related stimuli. Altered reward processing, complex conditioning processes, impaired reinforcement learning, and increased salience attribution to alcohol-associated stimuli enable alcohol cues to drive alcohol seeking and consumption. Finally, we will discuss how the neurobiological and neurochemical mechanisms of alcohol-associated alterations in reward processing and learning can interact with stress, cognition, and emotion processing.

Impact of tobacco smoke constituents on nicotine-seeking behavior in adolescent and adult male rats

INTRODUCTION

Given the rapid increase in teen vaping over recent years it is critical to understand mechanisms underlying addiction and relapse to tobacco use at this age. To evaluate the role of non-nicotine constituents in cigarette smoke, our lab has previously established a model of intravenous self-administration of aqueous cigarette smoke extract (CSE). We now compare the sensitivity of male adolescent and adult rats who have self-administered CSE or nicotine to reinstatement with the pharmacological stressor, yohimbine, with and without cues.

METHODS

Adolescents and adults, aged postnatal day (P) 34 and 84, were tested for the effect of yohimbine (0-2.5 mg/kg) on plasma corticosterone levels to establish a dose that was an effective stressor at both ages. Separate groups of animals were trained to lever press for food before beginning 1-hour drug self-administration sessions for nicotine or CSE (15 μg/kg/infusion nicotine content). Once stable responding was reached, drug was removed, and behavior extinguished. Drug-seeking behavior was reinstated with yohimbine, cues, or a combination of yohimbine and cues.

RESULTS

Although adolescents and adults showed different dose-responses for yohimbine-induced corticosterone release, a dose of 2.5 mg/kg increased stress hormone levels at both ages. Whereas both ages displayed similar responding for CSE and nicotine, adolescents self-administered more CSE and nicotine as compared to adults. Cues and cues + stress reinstated responding to a greater extent in animals that had self-administered CSE, regardless of age.

DISCUSSION

These findings suggest that non-nicotine tobacco smoke constituents influence later but not earlier stages of addiction in both adolescent and adult male rats.

A randomized wait-list controlled trial to investigate the role of cognitive mechanisms in parenting interventions on mothers with substance use disorder

Background

Maternal substance use disorder (SUD) represents a risk condition for quality of parenting and child development. The current literature highlights the need to identify interventions that effectively enhance the quality of parenting and to better understand which mechanisms are involved in the process of change. The present study protocol describes a randomized wait-list controlled trial that aims to examine (1) the efficacy of the Video-feedback Intervention to promote Positive Parenting and Sensitive Discipline (VIPP-SD) in improving the quality of parenting (i.e., sensitive parenting and sensitive discipline) in mothers with SUD, (2) whether the intervention affects parental cognitive mechanisms (i.e., attentional disengagement to infant negative emotions, inhibitory control confronted with children’s affective expression, and parental reflective functioning), and (3) whether changes in these processes act as mechanisms of change, mediating the effect of the VIPP-SD program on quality of parenting. Moreover, the study aims (4) to explore whether the VIPP-SD has an effect on parenting stress and (5) to compare mothers with SUD to low-risk mothers on the outcome measures.

Methods

The study will involve 40 mothers with SUD and 20 low-risk mothers of children aged between 14 months and 6 years old. Mothers in the SUD group will be randomly divided into two groups, one receiving the intervention (SUD experimental group) and one undergoing treatment as usual (SUD control group). All the mothers will be assessed pre-test and post-test. Quality of parenting will be assessed through observed parenting behaviors, whereas parental cognitive mechanisms will be assessed through neuropsychological tasks and self-report measures.

Discussion

The results of the study will reveal whether an intervention that has been proven effective in other at-risk samples is also effective in improving parenting behaviors in the context of SUD. The results will also provide insight into potential cognitive mechanisms involved in the process of change.

Trial registration

ISRCTN registry ISRCTN63070968. Registered on 25 June 2021. Retrospectively registered

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-022-06420-8.

Prelimbic cortex neural encoding dynamically tracks expected outcome value

Animals must modify their behavior based on updated expected outcomes in a changing environment. Prelimbic cortex (PrL) neural encoding during learning predicts, and is necessary for, appropriately altering behavior based on a new expected outcome value following devaluation. We aimed to determine how PrL neural activity encodes reward predictive cues after the expected outcome value of those cues is decreased following conditioned taste aversion. In one post-devaluation session, rats were tested under extinction to determine their ability to alter their behavior to the expected outcome values (i.e., extinction test). In a second post-devaluation session, rats were tested with the newly devalued outcome delivered so that the rats experienced the updated outcome value within the session (i.e., re-exposure test). We found that PrL neural encoding of the cue associated with the devalued reward predicted the ability of rats to suppress behavior in the extinction test session, but not in the re-exposure test session. While all rats were able to successfully devalue the outcome during conditioned taste aversion, a subset of rats continued to consume the devalued outcome in the re-exposure test session. We found differential patterns of PrL neural encoding in the population of rats that did not avoid the devalued outcome during the re-exposure test compared to the rats that successfully avoided the devalued outcome. Our findings suggest that PrL neural encoding dynamically tracks expected outcome values, and differential neural encoding in the PrL to reward predictive cues following expected outcome value changes may contribute to distinct behavioral phenotypes.

Prevalence, demographics, and cognitive dysfunction among methamphetamine-dependent individuals with childhood maltreatment

Previous studies have shown that dependent individuals (DIs) have higher rates of childhood maltreatment and poorer cognitive performance compared with healthy controls. However, little attention has been paid to the cognitive dysfunction of DIs with childhood maltreatment. The purpose of this study was to explore the cognitive deficits of maltreated methamphetamine-dependent individuals (METH-DIs) using a cross-sectional and case-control design. In addition, we aimed to examine the prevalence of childhood maltreatment and the demographic and clinical characteristics of Chinese male METH-DIs. 330 METH-DIs and 143 healthy controls were recruited and completed a detailed questionnaire on demographic and drug-related variables. Childhood abuse data were collected from the Childhood Trauma Questionnaire-Short Form (CTQ-SF). Cognitive function was assessed by the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). The Beck Depression Inventory, Beck Anxiety Inventory, and Visual Analogue Scale (VAS) were used to assess the clinical state of the METH-DIs. 166 of 326 (50.9%) METH-DIs had experienced at least one type of childhood maltreatment. Maltreated METH-DIs were more likely to have a lower level of education (t₃₂₄ = 5.81, p < 0.001), a higher level of depression(t₃₂₄ = －2.68, p < 0.01), and a younger onset age of drug use (t₃₂₄ = 3.58, p < 0.01) than METH-DIs who had no experience of childhood maltreatment. Maltreated METH-DIs also performed worse on the RBANS attention score than METH-DIs who did not experience maltreatment (F_1,324 = 15.41, p < 0.001, partial η² = 0.05). Our findings revealed that some demographic and clinical variables were associated with maltreatment among METH-DIs. Moreover, attention dysfunction was found in maltreated METH-DIs, which conforms to the theory of latent vulnerability.

Assessing the attentional bias of smokers in a virtual reality anti-saccade task using eye tracking

INTRODUCTION

Cognitive biases (among them attentional bias, AB) are considered an important factor in the development, maintenance, and recurrence of addiction. However, traditional paradigms to measure AB have been criticized regarding external validity and methodical issues. Therefore, and because the neurophysiological correlates of anti-saccade tasks are known, we implemented a novel smoking anti-saccade task in virtual reality (VR) to measure AB and inhibitory control in different contexts and with higher ecological validity.

METHODS

Smokers (n = 20) and non-smokers (n = 20) were tested on a classic pro- and anti-saccade task, a VR anti-saccade task and a VR attention fixation task (all containing smoking-related and neutral stimuli) while eye-tracking data was collected. Two VR contexts (park and office room) were applied.

RESULTS

Saccade latencies were significantly higher for the smoking group in the VR anti-saccade task. However, this effect did not differ between smoking-related and neutral stimuli, thus overall no AB was observed. Instead, AB was only present in the park context. Additionally, saccade latencies and error rates were significantly higher in the park context.

CONCLUSIONS

Results indicate impaired inhibitory control in smokers relative to non-smokers. The lack of evidence for a general AB might be due to the lower severity of smoking dependence in the smoking sample. Instead, results suggest context specificity of AB. Implications for smoking cessation interventions in the field of inhibitory control training and attention bias modification are discussed.

Anomalies in global network connectivity associated with early recovery from alcohol dependence: A network transcranial magnetic stimulation and electroencephalography study

Although previous research in alcohol dependent populations identified alterations within local structures of the addiction ‘reward’ circuitry, there is limited research into global features of this network, especially in early recovery. Transcranial magnetic stimulation (TMS) is capable of non‐invasively perturbing the brain network while electroencephalography (EEG) measures the network response. The current study is the first to apply a TMS inhibitory paradigm while utilising network science (graph theory) to quantify network anomalies associated with alcohol dependence. Eleven individuals with alcohol‐dependence (ALD) in early recovery and 16 healthy controls (HC) were administered 75 single pulses and 75 paired‐pulses (inhibitory paradigm) to both the left and right prefrontal cortex (PFC). For each participant, Pearson cross‐correlation was applied to the EEG data and correlation matrices constructed. Global network measures (mean degree, clustering coefficient, local efficiency and global efficiency) were extracted for comparison between groups. Following administration of the inhibitory paired‐pulse TMS to the left PFC, the ALD group exhibited altered mean degree, clustering coefficient, local efficiency and global efficiency compared to HC. Decreases in local efficiency increased the prediction of being in the ALD group, while all network metrics (following paired‐pulse left TMS) were able to adequately discriminate between the groups. In the ALD group, reduced mean degree and global clustering was associated with increased severity of past alcohol use. Our study provides preliminary evidence of altered network topology in patients with alcohol dependence in early recovery. Network anomalies were predictive of high alcohol use and correlated with clinical features of alcohol dependence. Further research using this novel brain mapping technique may identify useful network biomarkers of alcohol dependence and recovery.

Impaired control in addiction involves cognitive distortions and unreliable self-control, not compulsive desires and overwhelmed self-control

Impaired control in addiction involves a characteristic but obscure kind of partial control. Certain aspects of control over drug use are clearly reduced, reflected in difficulty cutting back and relapse. However, other aspects of control are clearly preserved, as reflected in substantial sensitivity to situational incentives-for example, the ability to defer use when needed. This juxtaposition is puzzling, and a clear mechanistically precise understanding of impaired control has yet to emerge. In this article, a Distortion model of impaired control is put forward. The key insight of the model is that the puzzling pattern of partial control seen in addiction can be understood in terms of unreliable control. The model posits large populations of distorted automatic thoughts (e.g., about drugs, one's self, one's circumstances, and one's abilities to cope), coupled with unreliable control over these distorted thoughts. These distorted thoughts, typically gradually and cumulatively, lead to illusion-like misvaluation of costs and benefits of drug use, in turn eventually leading to decisions to use. The model captures an elusive middle ground in addiction in which substantially preserved control over drug use for briefer intervals coexists with difficulty maintaining sobriety over the long-term. Moreover, the model explains a range of clinical findings in addiction that are not easily accommodated on leading alternative views.

Aversive drug cues reduce cigarette craving and increase prefrontal cortex activation during processing of cigarette cues in quitting motivated smokers

Aversive drug cues can be used to support smoking cessation and create awareness of negative health consequences of smoking. Better understanding of the effects of aversive drug cues on craving and the processing of appetitive drug cues in abstinence motivated smokers is important to further improve their use in cessation therapy and smoking-related public health measures. In this study, 38 quitting motivated smokers underwent functional magnetic resonance imaging (fMRI) scanning while performing a novel extended cue-reactivity paradigm. Pictures of cigarettes served as appetitive drug cues, which were preceded by either aversive drug cues (e.g., smokers' leg) or other cues (neutral or alternative reward cues). Participants were instructed to rate their craving for cigarettes after presentation of drug cues. When aversive drug cues preceded the presentation of appetitive drug cues, behavioural craving was reduced and activations in prefrontal (dorsolateral prefrontal cortex) and paralimbic (dorsal anterior cingulate cortex [dACC] and anterior insulae) areas were enhanced. A positive association between behavioural craving reduction and neurofunctional activation changes was shown for the right dACC. Our results suggest that aversive drug cues have an impact on the processing of appetitive drug cues, both on a neurofunctional and a behavioural level. A proposed model states that aversive drug-related cues activate control-associated brain areas (e.g., dACC), leading to increased inhibitory control on reward-associated brain areas (e.g., putamen) and a reduction in subjective cravings.

A Personalized Approach Bias Modification Smartphone App ("SWiPE") to Reduce Alcohol Use: Open-Label Feasibility, Acceptability, and Preliminary Effectiveness Study

Background

Approach bias modification (ApBM), a computerized cognitive intervention that trains people to “avoid” alcohol-related images and “approach” nonalcohol images, reduces the likelihood of relapse when administered during residential alcohol treatment. However, most individuals experiencing alcohol problems do not require, do not seek, or have difficulty accessing residential treatment. Smartphone-delivered ApBM could offer an easily accessible intervention to reduce alcohol consumption that can be personalized (eg, allowing selection of personally relevant alcohol and positive nonalcohol training images) and gamified to optimize engagement.

Objective

We examined the feasibility, acceptability, and preliminary effectiveness of “SWiPE,” a gamified, personalized alcohol ApBM smartphone app, and explored alcohol consumption and craving outcomes in people drinking at hazardous levels or above (Alcohol Use Disorders Identification Test [AUDIT] score ≥8) who wanted to reduce their alcohol use.

Methods

In this open-label trial, frequency and quantity of alcohol consumption, alcohol dependence severity, and craving were measured prior to participants downloading SWiPE. Participants (n=1309) were instructed to complete at least 2 sessions per week for 4 weeks. Recruitment and completion rates were indicators of feasibility. Functionality, aesthetics, and quality ratings were indicators of acceptability. Participants were prompted to report frequency and quantity of alcohol consumption weekly during training and 1 month after training. They completed measures of craving and dependence after 4 weeks of training.

Results

We recruited 1309 participants (mean age 47.0, SD 10.0 years; 758/1309, 57.9% female; mean AUDIT score 21.8, SD 6.5) over 6 months. Participants completed a median of 5 sessions (IQR 2-9); 31.2% (409/1309) completed ≥8 sessions; and 34.8% (455/1309) completed the posttraining survey. Mean Mobile Application Rating Scale scores indicated good acceptability for functionality and aesthetics and fair acceptability for subjective quality. Among those who completed the posttraining assessment, mean past-week drinking days reduced from 5.1 (SD 2.0) pre-training to 4.2 (SD 2.3) in week 4 (t₄₅₄=7.87; P<.001), and mean past-week standard drinks reduced from 32.8 (SD 22.1) to 24.7 (SD 20.1; t₄₅₄=8.58; P<.001). Mean Craving Experience Questionnaire frequency scores reduced from 4.5 (SD 2.0) to 2.8 (SD 1.8; t₄₃₅=19.39; P<.001). Severity of Dependence scores reduced from 7.7 (SD 3.0) to 6.0 (SD 3.2; t₄₃₅=12.44; P<.001). For the 19.4% (254/1309) of participants who completed a 1-month follow-up, mean past-week drinking days and standard drinks were 3.9 (SD 2.5) and 23.9 (SD 20.7), respectively, both significantly lower than at baseline (P<.001).

Conclusions

The findings suggest SWiPE is feasible and acceptable and may be effective at reducing alcohol consumption and craving in a predominantly nontreatment-seeking sample of adult Australians drinking at hazardous levels. SWiPE’s efficacy, relative to a control condition, now needs establishing in a randomized controlled trial. Smartphone-delivered personalized ApBM could be a highly scalable, widely accessible support tool for reducing alcohol use.

Trial Registration

Australian New Zealand Clinical Trials Registry ACTRN12620000638932; https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?ACTRN=12620000638932p

International Registered Report Identifier (IRRID)

RR2-10.2196/21278

The Effects of Combined Physical and Cognitive Training on Inhibitory Control: A Systematic Review and Meta-Analysis

While strong inhibitory control is critical for health and wellbeing, there are no broadly applicable effective behavioural interventions that enhance it. This meta-analysis examined the neurocognitive rationale for combined physical and cognitive training and synthesised the rapidly growing body of evidence examining combined paradigms to enhance inhibitory control. Across the research to date, there was a small positive effect (n studies = 16, n participants = 832) of combined training on improving inhibitory control. Sub-group analyses showed small-moderate positive effects when the physical component of the combined training was moderately intense, as opposed to low or vigorous intensities; moderate positive effects were found in older adults, as compared to adolescents and adults; and healthy individuals and those with vascular cognitive impairment, as compared to ADHD, ASD, mild cognitive impairment and cancer survivors. This is the first meta-analysis to provide evidence that combined physical, specifically when moderately intense, and cognitive training has the capacity to improve inhibitory control, particularly when delivered to healthy individuals and those experiencing age-related decline.

Top-down and bottom-up attentional biases for smoking-related stimuli: Comparing dependent and non-dependent smokers

INTRODUCTION

Substance use causes attentional biases for substance-related stimuli. Both bottom-up (preferential processing) and top-down (inhibitory control) processes are involved in attentional biases. We explored these aspects of attentional bias by using dependent and non-dependent cigarette smokers in order to see whether these two groups would differ in terms of general inhibitory control, bottom-up attentional bias, and top-down attentional biases. This enables us to see whether consumption behaviour would affect these cognitive responses to smoking-related stimuli.

METHODS

Smokers were categorised as either dependent (N = 26) or non-dependent (N = 34) smokers. A further group of non-smokers (N = 32) were recruited to act as controls. Participants then completed a behavioural inhibition task with general stimuli, a smoking-related eye tracking version of the dot-probe task, and an eye-tracking inhibition task with smoking-related stimuli.

RESULTS

Results indicated that dependent smokers had decreased inhibition and increased attentional bias for smoking-related stimuli (and not control stimuli). By contrast, a decreased inhibition for smoking-related stimuli (in comparison to control stimuli) was not observed for non-dependent smokers.

CONCLUSIONS

Preferential processing of substance-related stimuli may indicate usage of a substance, whereas poor inhibitory control for substance-related stimuli may only emerge if dependence develops. The results suggest that how people engage with substance abuse is important for top-down attentional biases.

Advances in understanding meso-cortico-limbic-striatal systems mediating risky reward seeking

The risk of an aversive consequence occurring as the result of a reward-seeking action can have a profound effect on subsequent behavior. Such aversive events can be described as punishers, as they decrease the probability that the same action will be produced again in the future and increase the exploration of less risky alternatives. Punishment can involve the omission of an expected rewarding event ("negative" punishment) or the addition of an unpleasant event ("positive" punishment). Although many individuals adaptively navigate situations associated with the risk of negative or positive punishment, those suffering from substance use disorders or behavioral addictions tend to be less able to curtail addictive behaviors despite the aversive consequences associated with them. Here, we discuss the psychological processes underpinning reward seeking despite the risk of negative and positive punishment and consider how behavioral assays in animals have been employed to provide insights into the neural mechanisms underlying addictive disorders. We then review the critical contributions of dopamine signaling to punishment learning and risky reward seeking, and address the roles of interconnected ventral striatal, cortical, and amygdala regions to these processes. We conclude by discussing the ample opportunities for future study to clarify critical gaps in the literature, particularly as related to delineating neural contributions to distinct phases of the risky decision-making process.

A double-blind sham-controlled phase 1 clinical trial of tDCS of the dorsolateral prefrontal cortex in cocaine inpatients: Craving, sleepiness, and contemplation to change

Impaired inhibitory control accompanied by enhanced salience attributed to drug-related cues, both associated with function of the dorsolateral prefrontal cortex (dlPFC), are hallmarks of drug addiction, contributing to worse symptomatology including craving. dlPFC modulation with transcranial direct current stimulation (tDCS) previously showed craving reduction in inpatients with cocaine use disorder (CUD). Our study aimed at assessing feasibility of a longer tDCS protocol in CUD (15 versus the common five/10 sessions) and replicability of previous results. In a randomized double-blind sham-controlled protocol, 17 inpatients with CUD were assigned to either a real-tDCS (right anodal/left cathodal) or a sham-tDCS condition for 15 sessions. Following the previous report, primary outcome measures were self-reported craving, anxiety, depression, and quality of life. Secondary measures included sleepiness, readiness to change drug use, and affect. We also assessed cognitive function including impulsivity. An 88% retention rate demonstrated feasibility. Partially supporting the previous results, there was a trend for self-reported craving to decrease in the real-tDCS group more than the sham-group, an effect that would reach significance with 15 subjects per group. Quality of life and impulsivity improved over time in treatment in both groups. Daytime sleepiness and readiness to change drug use showed significant Group × Time interactions whereby improvements were noted only in the real-tDCS group. One-month follow-up suggested transient effects of tDCS on sleepiness and craving. These preliminary results suggest the need for including more subjects to show a unique effect of real-tDCS on craving and examine the duration of this effect. After replication in larger sample sizes, increased vigilance and motivation to change drug use in the real-tDCS group may suggest fortification of dlPFC-supported executive functions.

A neural mechanism of the relationship between impulsivity and emotion dysregulation in patients with Internet gaming disorder

Impulsivity and emotion dysregulation have been known to be risk factors for Internet gaming disorder (IGD), but their underlying neural mechanisms are not yet fully understood. Given that the prefrontal cortex has a key role in higher order cognition and addiction, the present study aimed to investigate emotional influences on response inhibition in situations with different cognitive demands. A total of 41 young male adults (20 with and 21 without IGD) were scanned while performing two versions of an emotional go/no-go task with demands on low and high working memory load. Patients with IGD showed a failure in response inhibition and increased activation of widespread brain regions, including prefrontal, motor-sensory, parietal, occipital, insula, and striatal regions across tasks. Among these regions, involvement of the dorsolateral prefrontal cortex and ventral striatum was observed only during the task with high demands on working memory. Moreover, it was also only during the high-load task that interaction between response inhibition and emotional states was observed in the dorsomedial prefrontal cortex, with observations revealing that its alteration in patients with IGD was associated with number of hours spent on Internet gaming. Our findings highlight a failure of response inhibition and dysfunction within the inhibitory control network. The special significance of our study is that dysfunctional dorsomedial prefrontal cortex may mediate abnormal emotional influences on response inhibition in patients with IGD.

Event-related brain response to visual cues in individuals with Internet gaming disorder: relevance to attentional bias and decision-making

This study investigated attentional bias toward game-related cues in Internet gaming disorder (IGD) using electrophysiological markers of late positive potential (LPP) and identifying the sources of LPP. In addition, the association between LPP and decision-making ability was investigated. The IGD (n = 40) and healthy control (HC; n = 39) participants viewed a series of game-related and neutral pictures, while their event-related potentials (ERPs) were recorded. LPPs were calculated as the mean amplitudes between 400 and 700 ms at the centro-parietal (CP3, CP1, Cpz, CP2, and CP4) and parietal (P3, P1, Pz, P2, and P4) electrode sites. The source activations of LPP were estimated using standardized low-resolution brain electromagnetic tomography (sLORETA). In addition, decision-making ability was evaluated by the Cambridge Gambling Task. Higher LPP amplitudes were found for game-related cues in the IGD group than in the HC group. sLORETA showed that the IGD group was more active in the superior and middle temporal gyri, which are involved in social perception, than in the HC group, whereas it was less active in the frontal area. Individuals with IGD have deficits in decision-making ability. In addition, in the HC group, the lower the LPP when looking at the game-related stimuli, the better the quality of decision-making, but not in the IGD group. Enhanced LPP amplitudes are associated with emotional arousal to gaming cues and decision-making deficits in IGD. In addition, source activities suggest that patients with IGD perceive game-related cues as social stimuli. LPP can be used as a neurophysiological marker of IGD.

Anabolic androgenic steroids, antisocial personality traits, aggression and violence

BACKGROUND

Anabolic androgenic steroid (AAS) use is associated with a wide range of adverse physical, psychological and social effects. While some experience few side effects, others might experience severe consequences. Aggression and violence are among the often-cited side effects associated with high-dose AAS use; however, most of the knowledge is generated from subgroups, such as prison populations. A likely hypothesis is that AAS use is associated with aggression and violence, but that these associations are complex and may be mediated by several factors, such as substance use, AAS dependence and personality traits.

METHODS

In the present study, we tested this hypothesis by examining the relations between long-term AAS use and AAS dependence, aggression, interpersonal violence and potential mediating factors in a sample of male AAS exposed and non-exposed weightlifting controls (WLC), using self-report questionnaires. Based upon AAS dependence criteria, a sample of male AAS users and WLC (N = 139) were stratified into three groups: WLC (n = 66), AAS dependents (n = 41) and AAS non-dependents (n = 32).

RESULTS

The results demonstrate that AAS dependents reported significantly higher levels of aggression compared to WLC and AAS non-dependents. While interpersonal violence was reported in all three groups, the highest percentage was found in the AAS dependent group.

CONCLUSION

In summary, our study confirms a link between AAS use, aggression and violence in a weightlifting population. However, the association is foremost seen in AAS dependent users and it seems that antisocial personality traits are an important mediator.

Feasibility and pilot efficacy of cognitive remediation for people in residential substance use treatment

INTRODUCTION

There are high rates of cognitive impairment among people seeking treatment for problematic substance use, which is rarely addressed in treatment programs. The aim of this pilot study was to evaluate the feasibility and outcomes of the neuropsychological and educational approach to cognitive remediation (NEAR) in a residential substance treatment setting.

METHODS

A non-randomised trial conducted between November 2018 and November 2019, compared outcomes for 34 residents who received cognitive remediation (CR) plus treatment as usual (TAU) to 31 residents who received TAU only. Number of groups and attendance, and a measure of client satisfaction assessed feasibility. Cognitive function was assessed at baseline (service admission), and at 2 and 6 months post-admission.

RESULTS

A total of 95 CR groups were delivered over a 36-week time period with a high degree of treatment fidelity and acceptability to participants. Cognitive outcomes improved across both the CR+TAU and TAU groups by 2 months, which was maintained at 6 months for outcomes related to executive functioning. There were no significant differences between the CR+TAU and TAU groups at 2 or 6 months, although a large effect size and confidence intervals indicated a potentially larger change in cognitive flexibility after receiving CR.

DISCUSSION AND CONCLUSIONS

This study contributes to our understanding of the implementation of CR in the alcohol and other drug rehabilitation setting. It is feasible to incorporate the NEAR program in treatment. The small sample size and lower than expected treatment dose likely contributed to the lack of significant findings.

Psychopathic traits, inhibition, and positive and negative emotion: Results from an emotional Go/No-Go task

Difficulty stopping unwanted or inappropriate actions (i.e., inhibitory control) is implicated in antisocial behaviors, which are common in people high in psychopathic traits. Recent research indicates that, for those with antisocial personality, inhibitory control is impaired under negative emotional contexts; however, it is unclear whether this impairment extends to persons with psychopathic traits and to impairments under positive emotional contexts. Identifying some of these distinctions can point to therapeutics that target negative emotion specifically or emotion dysregulation broadly. We sought to identify unique relationships between distinct facets of psychopathy and inhibitory control in the context of positive, negative, and neutral stimuli. Using a community sample (N = 117), event-related potentials were recorded during an emotional-linguistic Go/No-Go task. Results indicated distinct cognition-emotion relationships for each psychopathy facet. Higher interpersonal facet scores related to reciprocal interference between cognition and emotion. Higher callous affect facet scores related to reduced inhibitory and emotional processing, except when stimuli were most engaging (emotional No-Go trials). Higher erratic lifestyle facet scores related to increased effort required to process both emotion and inhibition cues. Finally, higher antisocial facet scores related to poorer behavioral inhibition overall. This research challenges the theoretical accounts of psychopathy focused on specific deficits in negative emotion, such as fearlessness, while offering some support for theories related to attentional dysfunction. Results also highlight the importance of facet-level theorizing, as results varied by facet. This study may inform efforts to reduce disinhibited behaviors, particularly in emotional contexts, among those high in certain psychopathic traits.

Prisoners of Addictive Cues: Biobehavioral Markers of Overweight and Obese Adults with Food Addiction

Obesity is associated with food and eating addiction (FA), but the biobehavioral markers of this condition are poorly understood. To characterize FA, we recruited 18 healthy controls and overweight/obese adults with (n = 31) and without (n = 17) FA (H-C, FAOB, NFAOB, respectively) to assess alpha brain asymmetry at rest using electroencephalogram; event-related potentials following exposure to high-calorie food (HCF), low-calorie food (LCF), and nonfood (NF) images in a Stroop paradigm; reaction time reflective of the Stroop bias; and symptoms of depression and disordered eating behavior. The FAOB group had the greatest emotional and uncontrollable eating, depressive, and binge-eating symptoms. The FAOB group displayed lower resting left alpha brain asymmetry than that of the NFAOB group. Differently from the other groups, the FAOB group presented attenuated Stroop bias following exposure to HCF relative to NF images, as well as a lower late positive potential component (LPPb; 450-495 ms) in both frontal and occipital regions. In the total cohort, a correlation was found between the Stroop bias and the LPPb amplitude. These results point to biobehavioral hypervigilance in response to addictive food triggers in overweight/obese adults with FA. This resembles other addictive disorders but is absent in overweight/obesity without FA.

Alcohol-related context modulates neural correlates of inhibitory control in alcohol dependent patients: Preliminary data from an fMRI study using an alcohol-related Go/NoGo-task

Alcohol use disorder (AUD) is characterized by both impaired inhibitory control and heightened cue reactivity, including enhanced craving and drinking urges in response to alcohol-related stimuli. The interaction between these two mechanisms is thought to be crucial in the maintenance of addiction and relapse. The present study used a newly developed alcohol-related Go/NoGo-task to investigate how exposure to alcohol-related cues affects neural processing of inhibitory control in subjects with AUD. Functional magnetic resonance imaging (fMRI) was recorded during performance of a Go/NoGo task, which incorporated alcohol-related and neutral stimuli as Go and NoGo trials in abstinent AUD patients and healthy controls (HC). AUD patients exhibited increased activation of a fronto-striatal-parietal network during successful response inhibition relative to HC. Within the AUD group, activation for alcohol-related (relative to neutral) inhibition was enhanced in regions including bilateral anterior cingulate cortex (ACC), right medial frontal and precentral gyri, and right putamen. Activation differences in the right ACC increased with subjective craving. These preliminary findings suggest that AUD patients need to recruit enhanced neuronal resources for successful inhibition. In parts of the inhibitory network, this hyperactivation is enhanced when inhibition takes place in an alcohol-related context. Activation in the ACC increased stronger in patients experiencing high craving, possibly because of an enhanced conflict. The task introduced here thus allows to investigate neural processing of alcohol-related inhibition in an AUD sample. The preliminary results suggest that exposure to alcohol-related cues intensifies the demand on an already challenged inhibitory system in recently abstinent patients with AUD.

Prefrontal cortical and nucleus accumbens contributions to discriminative conditioned suppression of reward-seeking

Fear can potently inhibit ongoing behavior, including reward-seeking, yet the neural circuits that underlie such suppression remain to be clarified. Prior studies have demonstrated that distinct subregions of the rodent medial prefrontal cortex (mPFC) differentially affect fear behavior, whereby fear expression is promoted by the more dorsal prelimbic cortex (PL) and inhibited by the more ventral infralimbic cortex (IL). These mPFC regions project to subregions of the nucleus accumbens, the core (NAcC) and shell (NAcS), that differentially contribute to reward-seeking as well as affective processes that may be relevant to fear expression. Here, we investigated how these mPFC and NAc subregions contribute to discriminative fear conditioning, assessed by conditioned suppression of reward-seeking. Bilateral inactivation of the NAcS or PL reduced the expression of conditioned suppression to a shock-associated CS+, whereas NAcC inactivation reduced reward-seeking without affecting suppression. IL inactivation caused a general reduction in conditioned suppression following discriminative conditioning, but not when using a single-stimulus design. Pharmacological disconnection of the PL → NAcS pathway revealed that this projection mediates conditioned suppression. These data add to a growing literature implicating discrete cortico-striatal pathways in the suppression of reward-seeking in response to aversive stimuli. Dysfunction within related structures may contribute to aberrant patterns of behavior in psychiatric illnesses including substance use disorders.

Effect of the mobile phone-related background on inhibitory control of problematic mobile phone use: An event-related potentials study

The present study aims to provide electrophysiological evidence for deficient inhibitory control in problematic mobile phone use and to investigate whether reduced inhibition is more pronounced during exposure to a mobile phone related background cue. A screen scale of smartphone addiction was completed by 227 college students, and finally an experimental group and a control group consisting of 20 problematic mobile phone users and 19 controls were included in the study. Event-related potentials were recorded during a backgrounded Go/NoGo task performed by those two groups, in which either a frequent Go signal (letter "M") or a rare NoGo signal (letter "W") was superimposed on three different background cues: neutral, mobile phone application-related and mobile phone using-related pictures. Results showed that problematic mobile phone users performed more commission errors than controls following mobile phone application background. Furthermore, problematic mobile phone users displayed a weaker NoGo P3 amplitude than controls on the mobile phone application background. The result might suggest that there is no general impairment of inhibitory control in problematic mobile phone use. The deficient inhibitory control on behavioral and psychophysiological level appeared merely in the mobile phone-related background. Such deficient stimuli-specific inhibitory control appears at the late stage of inhibitory control. Prevention programs should be designed to curtail exposure to the mobile phone-related stimulus and enhance cognitive control of potential problematic mobile phone users.

Personalized Approach Bias Modification Smartphone App ("SWIPE") to Reduce Alcohol Use Among People Drinking at Hazardous or Harmful Levels: Protocol for an Open-Label Feasibility Study

Background

Alcohol accounts for 5.1% of the global burden of disease and injury, and approximately 1 in 10 people worldwide develop an alcohol use disorder. Approach bias modification (ABM) is a computerized cognitive training intervention in which patients are trained to “avoid” alcohol-related images and “approach” neutral or positive images. ABM has been shown to reduce alcohol relapse rates when delivered in residential settings (eg, withdrawal management or rehabilitation). However, many people who drink at hazardous or harmful levels do not require residential treatment or choose not to access it (eg, owing to its cost, duration, inconvenience, or concerns about privacy). Smartphone app–delivered ABM could offer a free, convenient intervention to reduce cravings and consumption that is accessible regardless of time and place, and during periods when support is most needed. Importantly, an ABM app could also easily be personalized (eg, allowing participants to select personally relevant images as training stimuli) and gamified (eg, by rewarding participants for the speed and accuracy of responses) to encourage engagement and training completion.

Objective

We aim to test the feasibility and acceptability of “SWIPE,” a gamified, personalized alcohol ABM smartphone app, assess its preliminary effectiveness, and explore in which populations the app shows the strongest indicators of effectiveness.

Methods

We aim to recruit 500 people who drink alcohol at hazardous or harmful levels (Alcohol Use Disorders Identification Test score≥8) and who wish to reduce their drinking. Recruitment will be conducted through social media and websites. The participants’ intended alcohol use goal (reduction or abstinence), motivation to change their consumption, and confidence to change their consumption will be measured prior to training. Participants will be instructed to download the SWIPE app and complete at least 2 ABM sessions per week for 4 weeks. Recruitment and completion rates will be used to assess feasibility. Four weeks after downloading SWIPE, participants will be asked to rate SWIPE’s functionality, esthetics, and quality to assess acceptability. Alcohol consumption, craving, and dependence will be measured prior to commencing the first session of ABM and 4 weeks later to assess whether these variables change significantly over the course of ABM.

Results

We expect to commence recruitment in August 2020 and complete data collection in March 2021.

Conclusions

This will be the first study to test the feasibility, acceptability, and preliminary effectiveness of a personalized, gamified ABM intervention smartphone app for hazardous or harmful drinkers. Results will inform further improvements to the app, as well as the design of a statistically powered randomized controlled trial to test its efficacy relative to a control condition. Ultimately, we hope that SWIPE will extend the benefits of ABM to the millions of individuals who consume alcohol at hazardous levels and wish to reduce their use but cannot or choose not to access treatment.

Trial Registration

Australian New Zealand Clinical Trials Registry (ANZCTR) ACTRN12620000638932p; https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?ACTRN=12620000638932p

International Registered Report Identifier (IRRID)

PRR1-10.2196/21278

Alpha-tACS effect on inhibitory control and feasibility of administration in community outpatient substance use treatment

BACKGROUND

Deficits in inhibitory control (IC) and distress tolerance (DT) are associated with substance use disorders (SUD) and post-treatment return to substance use. Transcranial alternating current stimulation (tACS) modulates the neural oscillations that are associated with the cognitive and affective mechanisms contributing to IC and DT. The aims of the current study were to examine the feasibility and acceptability of administering tACS in a community-based SUD treatment setting, and to test the effect of alpha-tACS on IC and DT.

METHOD

A double-blind, randomized, active sham-controlled trial of treatment-seeking adults with a SUD (N = 30, Mean_age = 43.2 years, 70.0% male). Participants attended two sessions and completed computerized inhibitory control and distress tolerance tasks while receiving tACS targeting the bilateral dorsolateral prefrontal cortex (DLPFC). Participants received sham-tACS and were then randomized to receive sham-, alpha-, or gamma-tACS within 2-3 days.

RESULTS

Treatment retention was 87%. Participant self-reported belief of having received tACS and mean side effect intensity ratings did not differ across conditions, with all side effect ratings in the absent to mild range. There was a large (d = 0.83) and significant effect of alpha-tACS on inhibitory control compared to sham-tACS (β = 1.78, SE = 0.65, 95 % CI: 0.41, 3.14, p<0.01). There were no significant effects of condition on distress tolerance.

CONCLUSIONS

To our knowledge, this is the first study of tACS in adults with a SUD. Our findings provide preliminary evidence for recruitment, retention, and administration feasibility of tACS in a community-based substance use treatment program and a beneficial effect of alpha-tACS on inhibitory control.

Nucleus Accumbens as a Novel Target for Deep Brain Stimulation in the Treatment of Addiction: A Hypothesis on the Neurochemical and Morphological Basis

Addiction is a major cause of mortality and morbidity. Apart from psychotropic substances, alcohol and nicotine remain the common addictive materials responsible for the majority of deaths. Conventional conservative therapies are beneficial to certain populations, but the majority may require interventional treatments such as deep brain stimulation (DBS) in view of increasing mortality from drug abuse in recent years. We present a brief review on a novel neuromodulation target of the nucleus accumbens (NA) and its promising role in the management of addiction. The three stages of the addiction cycle are known to be mediated by dopaminergic pathways located in the mesolimbic dopamine system with connections to dorsal striatum, extended amygdala, cingulate gyrus, orbitofrontal cortex, prefrontal cortex, and ventral tegmental area. Recent advanced neuroimaging in humans and several animal studies demonstrated NA to be a vital anatomical area modulating this network. DBS of NA in animals reduced addictive behavior to alcohol, cocaine, and other narcotics significantly. The accidental observation that DBS of NA for psychiatric illnesses induced relief from addiction to alcohol and smoking has encouraged further research of late. Bilateral NA ablative surgery had shown nonrelapse in more than 50% of cases. Small series of patients have benefited so far from DBS of NA, but larger numbers are required to provide evidence-based treatment. The modulation of dopaminergic pathways through DBS of NA as a valid treatment for addiction is substantiated extensively by animal studies and also in a few clinical studies. However, this needs to be validated by a well-structured, multicenter controlled study in a large group of patients suffering from substance abuse.

Basal ganglia volume and shape in anorexia nervosa

Background

Reward-centred models have proposed that anomalies in the basal ganglia circuitry that underlies reward learning and habit formation perpetuate anorexia nervosa (AN). The present study aimed to investigate the volume and shape of key basal ganglia regions, including the bilateral caudate, putamen, nucleus accumbens (NAcc), and globus pallidus in AN.

Methods

The present study combined data from two existing studies resulting in a sample size of 46 women with AN and 56 age-matched healthy comparison (HC) women. Group differences in volume and shape of the regions of interest were examined. Within the AN group, the impact of eating disorder characteristics on volume and shape of the basal ganglia regions were also explored.

Results

The shape analyses revealed inward deformations in the left caudate, right NAcc, and bilateral ventral and internus globus pallidus, and outward deformations in the right middle and posterior globus pallidus in the AN group.

Conclusions

The present findings appear to fit with the theoretical models suggesting that there are alterations in the basal ganglia regions associated with habit formation and reward processing in AN. Further investigation of structural and functional connectivity of these regions in AN as well as their role in recovery would be of interest.

Persistence of value-modulated attentional capture is associated with risky alcohol use

BACKGROUND

This study examined how risky patterns of alcohol use might be related to the persistence of learned attentional capture during reversal of stimulus-reward contingencies.

METHODS

Participants were 122 healthy adults (mean age 21 years, 66% female) who completed an assessment including a visual search task to measure value-modulated attentional capture, with a reversal phase following a period of initial training. The assessment also included questions about alcohol use.

RESULTS

Overall, attentional capture was greater for distractors associated with high reward than for those associated with low reward, replicating previous findings of value-modulated attentional capture. When stimulus-reward contingencies were reversed, a higher persistence of learned attentional capture was associated with risky patterns of alcohol use.

CONCLUSION

This result highlights how value-modulated attentional capture may persist and is associated with risky alcohol use in a non-clinical sample. Future research (potentially with clinical samples of heavy drinkers) aimed towards understanding the mechanisms that drive these reversal deficits, and their relation to other compulsive behaviours, may provide important insights into the development and maintenance of addictive behaviours.

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.

Growth Mindset Can Reduce the Adverse Effect of Substance Use on Adolescent Reasoning

The present study examined the relationship between substance use and reasoning in adolescents, and further investigated the modulation role of growth mindset on this relationship. A total of 1759 adolescents in China with substance use experience were investigated. The results showed that substance use (smoking, drinking, and illicit drug use) was negatively correlated with reasoning (r = -0.24 ∼-0.39, p < 0.01) and growth mindset (r = -0.18 ∼-0.32, p < 0.01). Regression analysis revealed that after controlling for the background variables (i.e., age, family annual income, and parents' educational level), only illicit drug use was the significant predictor of reasoning (β = -0.325, t = -14.28, p < 0.001). The interaction effect between growth mindset and illicit drug use was also a significant predictor of reasoning (β = -0.067, t = -2.92, p = 0.004), indicating growth mindset modulated the relationship between illicit drug use and reasoning ability. Further analysis found that the negative correlation between frequency of illicit drug use and reasoning in high growth mindset group was weaker than that of low growth mindset group (F _{( 3 , 1733 )} = 332.51, p < 0.001, f ² = 0.22). This suggests that growth mindset plays a significant moderating role in the relationship between substance use and reasoning. Overall, substance use has adverse effect on adolescent reasoning, however, growth mindset could reduce this adverse effect.

Naltrexone differentially modulates the neural correlates of motor impulse control in abstinent alcohol-dependent and polysubstance-dependent individuals

Identifying key neural substrates in addiction disorders for targeted drug development remains a major challenge for clinical neuroscience. One emerging target is the opioid system, where substance-dependent populations demonstrate prefrontal opioid dysregulation that predicts impulsivity and relapse. This may suggest that disturbances to the prefrontal opioid system could confer a risk for relapse in addiction due to weakened 'top-down' control over impulsive behaviour. Naltrexone is currently licensed for alcohol dependence and is also used clinically for impulse control disorders. Using a go/no-go (GNG) task, we examined the effects of acute naltrexone on the neural correlates of successful motor impulse control in abstinent alcoholics (AUD), abstinent polysubstance-dependent (poly-SUD) individuals and controls during a randomised double blind placebo controlled fMRI study. In the absence of any differences on GNG task performance, the AUD group showed a significantly greater BOLD response compared to the control group in lateral and medial prefrontal regions during both placebo and naltrexone treatments; effects that were positively correlated with alcohol abstinence. There was also a dissociation in the positive modulating effects of naltrexone in the orbitofrontal cortex (OFC) and anterior insula cortex (AIC) of the AUD and poly-SUD groups respectively. Self-reported trait impulsivity in the poly-SUD group also predicted the effect of naltrexone in the AIC. These results suggest that acute naltrexone differentially amplifies neural responses within two distinct regions of a salience network during successful motor impulse control in abstinent AUD and poly-SUD groups, which are predicted by trait impulsivity in the poly-SUD group.

Structural brain characteristics of anabolic-androgenic steroid dependence in men

AIM

To identify differences in brain morphology between dependent and non-dependent male anabolic-androgenic steroid (AAS) users.

DESIGN

This study used cross-sectional data from a longitudinal study on male weightlifters.

PARTICIPANTS

Oslo University Hospital, Norway.

SETTING

Eighty-one AAS users were divided into two groups; AAS-dependent (n = 43) and AAS-non-dependent (n = 38).

MEASUREMENTS

Neuroanatomical volumes and cerebral cortical thickness were estimated based on magnetic resonance imaging (MRI) using FreeSurfer. Background and health information were obtained using a semi-structured interview. AAS-dependence was evaluated in a standardized clinical interview using a version of the Structured Clinical Interview for DSM-IV, adapted to apply to AAS-dependence.

FINDINGS

Compared with non-dependent users, dependent users had significantly thinner cortex in three clusters of the right hemisphere and in five clusters of the left hemisphere, including frontal, temporal, parietal and occipital regions. Profound differences were seen in frontal regions (left pars orbitalis, cluster-wise P < 0.001, right superior frontal, cluster-wise P < 0.001), as has been observed in other dependencies. Group differences were also seen when excluding participants with previous or current non-AAS drug abuse (left pre-central, cluster-wise P < 0.001, left pars orbitalis, cluster-wise P = 0.010).

CONCLUSION

Male dependent anabolic-androgenic steroid users appear to have thinner cortex in widespread regions, specifically in pre-frontal areas involved in inhibitory control and emotional regulation, compared with non-dependent anabolic-androgenic steroid users.

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.

Dysregulation as a correlate of cannabis use and problem use

OBJECTIVE

Cannabis users with a dysregulatory risk factor may be particularly vulnerable to engaging in more frequent and problematic cannabis use. Contemporary models of dysregulated behavior suggest that dysregulation emerges due to distinct mechanisms. The current study seeks to examine the dysregulatory correlates of cannabis involvement, including working memory capacity, delay discounting, impulsivity, and reward sensitivity.

METHOD

Participants were 104 non-treatment seeking frequent cannabis users (the average participant used cannabis 71% of the days/past 60 days [SD = 22%], with an average of two uses per day [SD = 1.2]). Mean age was 21.3 (SD = 4.3); 36.5% were female. Working memory was assessed via the Trail-Making Test-B and the Digit Span subtests of the WAIS-III, delay discounting was assessed via a computer-based task, trait impulsivity was self-reported via the Barratt Impulsiveness Scale, and reward sensitivity was self-reported via the Reward Dependence Scale and the Snaith-Hamilton Pleasure Scale.

RESULTS

Structural equation modeling estimated the associations between different facets of dysregulation and cannabis involvement. Results suggest that poor working memory capacity and high trait impulsivity were associated with both use and problem use. Greater delay discounting was associated with problem use, but not with frequency of use. Low reward sensitivity was associated with more frequent cannabis use, but not with problem use.

CONCLUSIONS

Results confirm that the dysregulatory correlates of cannabis involvement consist of multiple dimensions of functioning. Prospective studies that assess the multidimensional structure of dysregulation and cannabis involvement are needed in order to disaggregate the dysregulatory antecedents and consequences of cannabis involvement.

Learning to resist the urge: a double-blind, randomized controlled trial investigating alcohol-specific inhibition training in abstinent patients with alcohol use disorder

Background

Alcohol use disorder (AUD) leads to a significant individual and societal burden. To achieve higher therapy success rates, therapeutic interventions still need to be improved. Most current neuroscientific conceptualizations of AUD focus on the imbalance between an enhanced automatic reaction to alcohol cues and impaired inhibition. Complementary to traditional relapse prevention strategies, novel computerized training interventions aim to directly alter these processes. This study tests a computerized alcohol-specific inhibition training in a large clinical sample and investigates its effects on behavioral, experimental and neurophysiological outcomes. It also analyzes whether variations in inhibition difficulty and/or endogenous cortisol levels during training impact these effects.

Methods

This is a double-blind, randomized controlled trial (RCT) with 246 inpatients with AUD participating. After baseline assessment, participants are randomly assigned to one of three computerized Go-NoGo-based inhibition training interventions (two alcohol-specific versions with different Go/NoGo ratios, or neutral control training) and one of two intervention times (morning/afternoon), resulting in six study arms. All patients perform six training sessions within 2 weeks. Endogenous cortisol is measured in 80 patients before and after the first training session. Inhibitory control and implicit associations towards alcohol are assessed pre and post training, at which point electroencephalography (EEG) is additionally measured in 60 patients. Patients’ alcohol consumption and relevant psychological constructs (e.g., craving, self-efficacy, treatment motivation) are measured at discharge and at 3-, 6- and 12-month follow-ups. Fifty healthy participants are assessed (20 with EEG) at one time point as a healthy control group.

Discussion

This study investigates the effects of a computerized, alcohol-specific inhibition training for the first time in patients with AUD. Results should give insight into the effectiveness of this potential add-on to standard AUD treatment, including proximal and distal measures and effects on behavioral, experimental and neurophysiological measures. Information about working mechanisms and potential optimizations of this training are gathered through variations regarding difficulty of inhibition training and training time. This study may thus contribute to a deepened understanding of AUD and the improvement of its evidence-based treatment.

Trial registration

ClinicalTrials.gov, ID: NCT02968537. Registered on 18 November 2016.

Electronic supplementary material

The online version of this article (10.1186/s13063-019-3505-2) contains supplementary material, which is available to authorized users.

Deficient Functioning of Frontostriatal Circuits During the Resolution of Cognitive Conflict in Cannabis-Using Youth

OBJECTIVE

Disturbances in self-regulatory control are involved in the initiation and maintenance of addiction, including cannabis use disorder. In adults, long-term cannabis use is associated with disturbances in frontostriatal circuits during tasks that require the engagement of self-regulatory control, including the resolution of cognitive conflict. Understudied are the behavioral and neural correlates of these processes earlier in the course of cannabis use disentangled from effects of long-term use. The present study investigated the functioning of frontostriatal circuits during the resolution of cognitive conflict in cannabis-using youth.

METHOD

Functional magnetic resonance imaging data were acquired from 28 cannabis-using youth and 32 age-matched healthy participants during the performance of a Simon task. General linear modeling was used to compare patterns of brain activation during correct responses to conflict stimuli across groups. Psychophysiologic interaction analyses were used to examine conflict-related frontostriatal connectivity across groups. Associations of frontostriatal activation and connectivity with cannabis use measures were explored.

RESULTS

Decreased conflict-related activity was detected in cannabis-using versus healthy control youth in frontostriatal regions, including the ventromedial prefrontal cortex, striatum, pallidum, and thalamus. Frontostriatal connectivity did not differ across groups, but negative connectivity between the ventromedial prefrontal cortex and striatum was detected in the 2 groups.

CONCLUSION

These findings are consistent with previous reports of cannabis-associated disturbances in frontostriatal circuits in adults and point to the specific influence of cannabis on neurodevelopmental changes in youth. Future studies should examine whether frontostriatal functioning is a reliable marker of cannabis use disorder severity and a potential target for circuit-based interventions.

Cell-type and projection-specific dopaminergic encoding of aversive stimuli in addiction

Drug addiction is a major public health concern across the world for which there are limited treatment options. In order to develop new therapies to correct the behavioral deficits that result from repeated drug use, we need to understand the neural circuit dysfunction that underlies the pathophysiology of the disorder. Because the initial reinforcing effects of drugs are dependent on increases in dopamine in reward-related brain regions such as the mesolimbic dopamine pathway, a large focus of addiction research has centered on the dysregulation of this system and its control of positive reinforcement and motivation. However, in addition to the processing of positive, rewarding stimuli, there are clear deficits in the encoding and valuation of information about potential negative outcomes and how they control decision making and motivation. Further, aversive stimuli can motivate or suppress behavior depending on the context in which they are encountered. We propose a model where rewarding and aversive information guides the execution of specific motivated actions through mesocortical and mesolimbic dopamine acting on D1- and D2- receptor containing neuronal populations. Volitional drug exposure alters the processing of rewarding and aversive stimuli through remodeling of these dopaminergic circuits, causing maladaptive drug seeking, self-administration in the face of negative consequences, and drug craving. Together, this review discusses the dysfunction of the circuits controlling different types of aversive learning as well as how these guide specific discrete behaviors, and provides a conceptual framework for how they should be considered in preclinical addiction models.

Brain response features during forced break could predict subsequent recovery in internet gaming disorder: A longitudinal study

Although internet gaming disorder (IGD) is associated with negative health measures, individuals may recover without professional intervention. Exploring neural features associated with natural recovery may provide insights into how best to promote health among people with IGD. Seventy-nine IGD subjects were scanned when they were performing cue-craving tasks before and after gaming was interrupted with a forced break. After one year, 20 individuals no longer met IGD criteria and were considered recovered. We compared brain responses in cue-craving tasks between these 20 recovered IGD subjects and 20 matched IGD subjects still meeting criteria at one year (persistent IGD). Recovered IGD subjects showed lower dorsolateral prefrontal cortex (DLPFC) activation than persistent IGD subjects to gaming cues at both pre- and post-gaming times. Significant group-by-time interactions were found in the bilateral DLPFC and insula, and these involved relatively decreased DLPFC and increased insula activation in the persistent IGD group during the forced break. Relatively decreased DLPFC activity and increased insula activity in response to gaming cues following recent gaming may underlie persistence of gaming. These findings suggest that executive control and interoceptive processing warrant additional study in understanding recovery from IGD.

Compulsivity in Alcohol Use Disorder and Obsessive Compulsive Disorder: Implications for Neuromodulation

Alcohol use Disorder (AUD) is one of the leading causes of morbidity and mortality worldwide. The progression of the disorder is associated with the development of compulsive alcohol use, which in turn contributes to the high relapse rate and poor longer term functioning reported in most patients, even with treatment. While the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) defines AUD by a cluster of symptoms, parsing its heterogeneous phenotype by domains of behavior such as compulsivity may be a critical step to improve outcomes of this condition. Still, neurobiological underpinnings of compulsivity need to be fully elucidated in AUD in order to better design targeted treatment strategies. In this manuscript, we review and discuss findings supporting common mechanisms between AUD and OCD, dissecting the construct of compulsivity and focusing specifically on characteristic disruptions in habit learning and cognitive control in the two disorders. Finally, neuromodulatory interventions are proposed as a probe to test compulsivity as key pathophysiologic feature of AUD, and as a potential therapy for the subgroup of individuals with compulsive alcohol use, i.e., the more resistant stage of the disorder. This transdiagnostic approach may help to destigmatize the disorder, and suggest potential treatment targets across different conditions.