A role for the right dorsolateral prefrontal cortex in enhancing regulation of both craving and negative emotions in internet gaming disorder: A randomized trial

Effects of bilateral tDCS over DLPFC on response inhibition, craving, and brain functional connectivity in Internet gaming disorder: A randomized, double-blind, sham-controlled trial with fMRI

Background and aims

Impaired inhibitory control accompanied by enhanced craving is hallmark of addiction. This study investigated the effects of transcranial direct current stimulation (tDCS) on response inhibition and craving in Internet gaming disorder (IGD). We examined the brain changes after tDCS and their correlation with clinical variables.

Methods

Twenty-four males with IGD were allocated randomly to an active or sham tDCS group, and data from 22 participants were included for analysis. Participants self-administered bilateral tDCS over the dorsolateral prefrontal cortex (DLPFC) for 10 sessions. Stop-signal tasks were conducted to measure response inhibition and participants were asked about their cravings for Internet gaming at baseline and post-tDCS. Functional magnetic resonance imaging data were collected at pre- and post-tDCS, and group differences in resting-state functional connectivity (rsFC) changes from the bilateral DLPFC and nucleus accumbens were examined. We explored the relationship between changes in the rsFC and behavioral variables in the active tDCS group.

Results

A significant group-by-time interaction was observed in response inhibition. After tDCS, only the active group showed a decrease in the stop-signal reaction time (SSRT). Although craving decreased, there were no significant group-by-time interactions or group main effects. The anterior cingulate cortex (ACC) showed group differences in post- versus pre-tDCS rsFC from the right DLPFC. The rsFC between the ACC and left middle frontal gyrus was negatively correlated with the SSRT.

Discussion and conclusion

Our study provides preliminary evidence that bilateral tDCS over the DLPFC improves inhibitory control and could serve as a therapeutic approach for IGD.

Comparative efficacy of different interventions on executive function in adolescents with internet use disorder

BACKGROUND

The formation and relapse of Internet use disorder (IUD) are related to the decline in executive function. Previous studies have indicated that exercise intervention and high-definition transcranial direct current stimulation (HD-tDCS) can improve the cognitive abilities of adolescents with IUD. However, the combined intervention's impact on executive function in these adolescents remains unclear. Therefore, this study aims to explore the effects and differences of multimodal exercise, HD-tDCS intervention, and combined intervention on the executive function of adolescents with IUD.

METHODS

Forty-eight adolescents with IUD were randomly assigned to the multimodal exercise group, HD-tDCS intervention group, combined intervention group, and control group. The intervention groups received 4 weeks of moderate-intensity multimodal exercise, HD-tDCS intervention (2 mA, 20min/session, 3 times/week), or combined multimodal exercise with HD-tDCS intervention. The control group received conventional educational learning. Executive function measurements were taken before intervention, after intervention, and 2 weeks post-intervention.

RESULTS

Compared to pre-intervention, different interventions effectively improved the behavioral performance of adolescents with IUD in executive function tasks. In comparison to single interventions, the combined intervention significantly outperformed multimodal exercise and HD-tDCS intervention in influencing the executive function (especially inhibitory control and working memory) in adolescents with IUD.

CONCLUSION

Combined multimodal exercise with HD-tDCS intervention proves to be an effective means of enhancing executive function in adolescents with IUD, particularly contributing to the improvement of explicit behavioral performance related to executive function.

Pharmacological management of gambling disorder: an update of the literature

INTRODUCTION

Gambling disorder (GD) is a mental health condition characterized by persistent and problematic betting behavior. GD generates distress and impairment, and treatment options include psychological and pharmacological interventions.

AREAS COVERED

This narrative review explores existing pharmacological treatments for GD. The following classes of medications were considered: opioid-receptor antagonists (e.g. naltrexone and nalmefene), serotonin reuptake inhibitors (e.g. fluvoxamine, paroxetine, sertraline, escitalopram, and citalopram), glutamatergic agents (e.g. N-acetylcysteine (NAC), acamprosate, and memantine), mood stabilizers (e.g. topiramate, carbamazepine, lithium), and other medications (e.g. modafinil, nefazodone, olanzapine, haloperidol, tolcapone, and bupropion).

EXPERT OPINION

Due to the limitations of the studies reviewed, solid conclusions regarding the optimal choice of pharmacotherapy for individuals with GD are challenging to draw at this time. Despite some medications, such as naltrexone and nalmefene, showing promising results, efficacy has varied across studies. The review highlights current gaps/limitations, including small sample sizes, limited diversity in participant demographics, the need for exploring different gambling subtypes and treatment responses, high placebo response rates, lack of longer-term longitudinal information, limited investigation of neurobiological correlates and co-occurring disorders, and the importance of implementation research. Further research is needed to address these gaps and explore additional medications, as well as interventions like neuromodulation.

Comparisons of clinical subtypes, symptom severity, global functioning, emotional and behavior problems, and CPT test profiles in children and adolescents with ADHD with and without co-occurring internet gaming disorder

OBJECTIVES

This study aims to assess whether the presence of Internet Gaming Disorder (IGD) is associated with disease severity, Attention Deficit Hyperactivity Disorder(ADHD) presentation, emotional problems, behavioral problems, and CPT profile in patients with ADHD.

METHOD

Forty children with IGD and sixty-four patients without IGD were included in the study, all of whom had a diagnosis of ADHD. Comorbid psychiatric disorders were determined using The Kiddie Schedule for Affective Disorders and Schizophrenia (K-SADS). Conners's Parent Rating Scale-Revised Short form (CPRS-RS), The Strengths and Difficulties Questionnaire (SDQ), Internet Gaming Disorder Questionnaire (IGD-20), and MOXO Continuous Performance Test (MOXO d-CPT) were performed on the children, and Clinical Global Impression (CGI), Children's Global Assessment Scale (CGAS), comorbidities and ADHD presentations were evaluated.

RESULTS

The IGD group was found to have the combined presentation of ADHD more commonly, and their CGI, CGAS, SDQ behavior problems subscale, cognitive problems, attention problems, and ADHD index in the CPRS-RS questionnaire were found to be higher (p < 0.05). No differences were found in attention, timing, impulsiveness, and hyperactivity scores in CPT between groups (p > 0.05).

CONCLUSION

Our study has shown that children with both ADHD and IGD had more severe symptoms, more behavioral problems, and differences regarding the prevalence of the ADHD presentations when compared to children having ADHD without IGD. Longitudinal studies with higher sample sizes are required to investigate this possible connection in the context of a cause-effect relationship and draw a conclusion.

Ten years of research on the treatments of internet gaming disorder: A scoping review and directions for future research

Background

Although internet gaming disorder (IGD) has been listed in section III of the DSM-5 for approximately 10 years, the study of treatments for IGD remains in early stages. Nonetheless, a summary of findings to date and discussion of future research needs are warranted.

Methods

The current study reviewed scientific treatment studies with control groups and randomized controlled trials. We summarized the strengths and weaknesses of different treatment strategies and identified gaps in the research literature that may inform the direction of future research efforts.

Results

Sixteen studies were reviewed. Existing treatment studies may be categorized into cognitive behavioural therapy (CBT), pharmacotherapies, non-invasive brain stimulation (NIBS), and others.

Conclusions

CBT is the most widely studied treatment strategy for IGD thus far. Future studies should consider IGD-specific CBT treatment strategies. Medication-based treatment should be implemented with caution. NIBS is promising, and future studies should explore the most efficacious parameters and targets. In addition, studies should consider sex differences in the treatment of IGD.

Treatment effects of therapeutic interventions for gaming disorder: A systematic review and meta-analysis

The prevalence of gaming disorder is assumed to be between 2%-5%. The treatment effect of different therapeutic interventions of gaming disorder has not been studied extensively. This systematic review and meta-analysis sought to identify all intervention studies on gaming disorder with a control group, determine the effect of the interventions, and examine moderators. Studies applying a therapeutic intervention and using an appropriate comparison group were identified by searching electronic databases, previous reviews, and reference lists. Data on type of treatment, name of outcome measurement, symptom level and other study characteristics were extracted and analyzed using meta-analysis and meta-regression. A total of 38 studies and 76 effect sizes, originating from 9524 participants were included. RoB2 and ROBINS-I risk of bias tools were used to assess within-study risk of bias. Correlational hierarchical models with robust variance estimation were fitted to effect size data and yielded a moderate summary estimate. Egger's sandwich test, funnel plot inspections, and other tests were conducted to assess risk of bias between studies. Results indicate that there may be an overall effect of therapeutic interventions for gaming disorder, but confidence in these findings is compromised by small-study effects, possible publication bias, a limited study pool, and a lack of standardization. The field needs more higher quality studies before the evidence-base can support reliable meta-analytic estimates.

Trust in Shared-Space Collaborative Robots: Shedding Light on the Human Brain

BACKGROUND

Industry 4.0 is currently underway allowing for improved manufacturing processes that leverage the collective advantages of human and robot agents. Consideration of trust can improve the quality and safety in such shared-space human-robot collaboration environments.

OBJECTIVE

The use of physiological response to monitor and understand trust is currently limited due to a lack of knowledge on physiological indicators of trust. This study examines neural responses to trust within a shared-workcell human-robot collaboration task as well as discusses the use of granular and multimodal perspectives to study trust.

METHODS

Sixteen sex-balanced participants completed a surface finishing task in collaboration with a UR10 collaborative robot. All participants underwent robot reliability conditions and robot assistance level conditions. Brain activation and connectivity using functional near infrared spectroscopy, subjective responses, and performance were measured throughout the study.

RESULTS

Significantly, increased neural activation was observed in response to faulty robot behavior within the medial and right dorsolateral prefrontal cortex (PFC). A similar trend was observed for the anterior PFC, primary motor cortex, and primary visual cortex. Faulty robot behavior also resulted in reduced functional connectivity strengths throughout the brain.

DISCUSSION

These findings implicate regions in the prefrontal cortex along with specific connectivity patterns as signifiers of distrusting conditions. The neural response may be indicative of how trust is influenced, measured, and manifested for human-robot collaboration that requires active teaming.

APPLICATION

Neuroergonomic response metrics can reveal new perspectives on trust in automation that subjective responses alone are not able to provide.

Brain responses to positive and negative events in individuals with internet gaming disorder during real gaming

Objective

This study sought to investigate brain responses to positive and negative events in individuals with internet gaming disorder (IGD) during real gaming as a direct assessment of the neural features of IGD. This investigation reflects the neural deficits in individuals with IGD while playing games, providing direct and effective targets for prevention and treatment of IGD.

Methods

Thirty subjects with IGD and fifty-two matched recreational game use (RGU) subjects were scanned while playing an online game. Abnormal brain activities during positive and negative events were detected using a general linear model. Functional connectivity (FC) and correlation analyses between neural features and addiction severity were conducted to provide additional support for the underlying neural features.

Results

Compared to the RGU subjects, the IGD subjects exhibited decreased activation in the dorsolateral prefrontal cortex (DLPFC) during positive events and decreased activation in the middle frontal gyrus (MFG), precentral gyrus and postcentral gyrus during negative events. Decreased FC between the DLPFC and putamen during positive events and between the MFG and amygdala during negative events were observed among the IGD subjects. Neural features and addiction severity were significantly correlated.

Conclusions

Individuals with IGD exhibited deficits in regulating game craving, maladaptive habitual gaming behaviors and negative emotions when experiencing positive and negative events during real game-playing compared to RGU gamers. These abnormalities in neural substrates during real gaming provide direct evidence for explaining why individuals with IGD uncontrollably and continuously engage in game playing, despite negative consequences.

Neuroimaging correlates of internet gaming disorder: Can we achieve the promise of translating understandings of brain functioning into clinical advances?

Objectives

Here we aimed to consider the neural factors associated with internet gaming disorder (IGD), as well as the associations between these factors and existing treatments for the disorder.

Methods

A narrative review was conducted.

Results

Pharmacological as well as psychological treatments for IGD may be associated with specific changes in multiple brain areas and circuits. In particular, fronto-striatal and subcortical regions and pathways appear relevant to IGD and its treatment.

Conclusions

Neuroimaging holds promise for identifying specific mechanisms underlying IGD interventions. However, to date, firm conclusions are difficult to draw and more research examining neural mechanisms of empirically supported treatments for IGD is needed.

A systematic review and meta-analysis of risky decision-making in specific domains of problematic use of the internet: Evidence across different decision-making tasks

This systematic review summarizes empirical evidence on risky decision-making (objective risk and ambiguity) in specific domains of problematic use of the internet (PUI) focusing on online addictive behaviors. We conducted a pre-registered (PROSPERO: CRD42020188452) PubMed search for PUI domains: gaming, social-network use, online buying-shopping, online pornography use, and unspecified PUI. We used the Newcastle-Ottawa Scale for quality assessment. Relevant studies were identified only for gaming (n = 19), social-network use (n = 8), unspecified PUI (n = 7), and online gambling (n = 1). The meta-analyses included 25 studies (2498 participants) comparing PUI and control groups regarding decision-making performance under objective risk and ambiguity. Across PUI domains, individuals with PUI compared to control participants showed more disadvantageous decision-making in measures of objective risk (g = -0.42 [-0.69, -0.16], p = .002) but not ambiguity (g = -0.22 [-0.47, -0.04], p = .096). PUI domain and gender were significant moderators. In the risk domain, effects were particularly present in gaming disorder, especially in exclusively male samples. Overall, the paucity of empirical studies in the considered area necessitates further research to identify probable gender- and disorder-specific cognitive relationships.

Effects of Transcranial Electrical Stimulation on Gambling and Gaming: A Systematic Review of Studies on Healthy Controls, Participants with Gambling/Gaming Disorder, and Substance Use Disorder

Gambling disorder (GD) and internet gaming disorder (IGD) are formally recognized behavioral addictions with a rapidly growing prevalence and limited treatment options. Recently, transcranial electrical stimulation (tES) techniques have emerged as potentially promising interventions for improving treatment outcomes by ameliorating cognitive functions implicated in addictive behaviors. To systematize the current state of evidence and better understand whether and how tES can influence gambling and gaming-related cognitive processes, we conducted a PRISMA-guided systematic review of the literature, focusing on tES effects on gaming and gambling in a diverse range of population samples, including healthy participants, participants with GD and IGD, as well as participants with substance abuse addictions. Following the literature search in three bibliographic databases (PubMed, Web of Science, and Scopus), 40 publications were included in this review, with 26 conducted on healthy participants, 6 focusing on GD and IGD patients, and 8 including participants with other addictions. Most of the studies targeted the dorsolateral prefrontal cortex, using transcranial direct current stimulation (tDCS), and assessed the effects on cognition, using gaming and gambling computerized cognitive tasks measuring risk taking and decision making, e.g., balloon analogue risk task, Iowa gambling task, Cambridge gambling task, etc. The results indicated that tES could change gambling and gaming task performances and positively influence GD and IGD symptoms, with 70% of studies showing neuromodulatory effects. However, the results varied considerably depending on the stimulation parameters, sample characteristics, as well as outcome measures used. We discuss the sources of this variability and provide further directions for the use of tES in the context of GD and IGD treatment.

Disrupted resting-state functional connectivity of frontal network in opium use disorder

Opioid use disorder (OUD) as a chronic relapsing disorder is initially driven by dysfunction of brain reward networks and associated with several psychiatric disorders. Resting-state EEG was recorded in 24 healthy participants as well as 31 patients with OUD. Healthy participants do not meet OUD criteria. After pre-processing of the raw EEG, functional connectivity in the frontal network using eLORETA and all networks using graph analysis method were calculated. Patients with OUD had higher electrical neuronal activity compared to healthy participants in higher frequency bands. The statistical analysis revealed that patients with OUD had significantly decreased phase synchronization in β1 and β2 frequency bands compared with the healthy group in the frontal network. Regarding global network topology, we found a significant decrease in the characteristic path length and an increase in global efficiency, clustering coefficient, and transitivity in patients compared with the healthy group. These changes indicated that local specialization and global integration of the brain were disrupted in OUD and it suggests a tendency toward random network configuration of functional brain networks in patients with OUD. Disturbances in EEG-based brain network indices might reflect an altered cortical functional network in OUD. These findings might provide useful biomarkers to understand cortical brain pathology in opium use disorder.

Use of experimental medicine approaches for the development of novel psychiatric treatments based on orexin receptor modulation

Despite progress in understanding the pathological mechanisms underlying psychiatric disorders, translation from animal models into clinical use remains a significant bottleneck. Preclinical studies have implicated the orexin neuropeptide system as a potential target for psychiatric disorders through its role in regulating emotional, cognitive, and behavioral processes. Clinical studies are investigating orexin modulation in addiction and mood disorders. Here we review performance-outcome measures (POMs) arising from experimental medicine research methods which may show promise as markers of efficacy of orexin receptor modulators in humans. POMs provide objective measures of brain function, complementing patient-reported or clinician-observed symptom evaluation, and aid the translation from preclinical to clinical research. Significant challenges include the development, validation, and operationalization of these measures. We suggest that collaborative networks comprising clinical practitioners, academics, individuals working in the pharmaceutical industry, drug regulators, patients, patient advocacy groups, and other relevant stakeholders may provide infrastructure to facilitate validation of experimental medicine approaches in translational research and in the implementation of these approaches in real-world clinical practice.

Potential Biological Markers and Treatment Implications for Binge Eating Disorder and Behavioral Addictions

The reward system is highly relevant to behavioral addictions such as gambling disorder (GD), internet gaming disorder (IGD), and food addiction/binge eating disorder (FA/BED). Among other brain regions, the ventral striatum (VS) has been implicated in reward processing. The main objective of the present state-of-the-art review was to explore in depth the specific role of the VS in GD, IGD and FA/BED, understanding it as a possible biomarker of these conditions. Studies analyzing brain changes following interventions for these disorders, and especially those that had explored possible treatment-related changes in VS, are discussed. More evidence is needed on how existing treatments (both pharmacological and psychobehavioral) for behavioral addictions affect the activation of the VS and related circuitry.

Emotional face expression recognition in problematic Internet use and excessive smartphone use: task-based fMRI study

Growing literature indicates that problematic Internet use (PIU) and excessive smartphone use (ESU) are associated with breakdown of functional brain networks. The effects of PIU&ESU on emotional face expression (EFE) recognition are not well understood, however behavioural investigations and fMRI studies of different addiction forms indicated the impairment of this function. The Facial Emotion Recognition Paradigm was used to probe cortico-limbic responses during EFE recognition. Combined fMRI and psychophysiological analysis were implemented to measure EFE-related functional brain changes in PIU&ESU. Self-reported questionnaires were used to assess PIU&ESU. Positive associations were found between the extent of PIU&ESU and functional connections related to emotional cognitive control and social brain networks. Our findings highlight the involvement of social functioning, especially EFE recognition in PIU&ESU. Therefore, we emphasize that besides the brain's executive and reward systems, the social brain network might be the next candidate to be involved in the pathogenesis of PIU&ESU.

Emotional bias modification weakens game-related compulsivity and reshapes frontostriatal pathways

Addiction is characterized by compulsive engagement despite adverse consequences. Psychobehavioural interventions targeting compulsivity in addictions are relatively rare, particularly for behavioural addictions like internet gaming disorder (IGD). Free from confounding drug-on-brain effects, IGD provides a promising model for understanding neuropsychological processes of addictions. IGD is a global concern in the setting of increasing internet use worldwide. Thus, developing interventions and understanding their mechanisms of action are important. Positive emotional association biases (EABs) towards addiction cues based on reward conditioning may underlie addiction-associated compulsivity. Here, we developed an EAB modification (EABM) protocol and examined whether modifying EABs via cognitive training would alter neurocognitive aspects of addiction-associated compulsivity in IGD. We recruited 90 IGD participants who were randomly assigned to receive EABM or sham training in a 1:1 ratio (clinicaltrials.gov identifier: NCT04068064). The EABM intervention involved six consecutive days of exposure to negative emotional terms linked to gaming stimuli and positive terms linked to non-gaming healthy-alternative stimuli. The sham training involved similar stimuli linked to neutral words. Participants underwent event-related functional MRI while performing a regulation-of-craving task and received several behavioural assessments pretraining and post-training. Primary efficacy measures were changes in gaming-related positive EABs, and compulsive gaming thoughts and behaviours. Behaviourally, EABM (versus sham) training decreased gaming-related positive EABs and compulsive gaming thoughts and behaviours. Neurally, EABM training involved decreased activation in the bilateral dorsal striatum in the regulation-of-craving task and altered left dorsal striatum-centric functional connectivity with ventral prefrontal cortical regions, which correlated with decreases in gaming-related EABs or compulsive gaming thoughts and behaviours. EABM training also implicated activation changes in the right medial frontal gyrus and posterior insula. EABM may reduce compulsive gaming thoughts and behaviours via reshaping functional organization of frontostriatal pathways and insular activity in IGD. The therapeutic potential of EABM should be examined in larger, longer-term studies, as should its application to other addictive disorders.

The World Federation of Societies of Biological Psychiatry guidelines on the assessment and pharmacological treatment of compulsive sexual behaviour disorder

OBJECTIVES

The current guidelines aim to evaluate the role of pharmacological agents in the treatment of patients with compulsive sexual behaviour disorder (CSBD). They are intended for use in clinical practice by clinicians who treat patients with CSBD.

METHODS

An extensive literature search was conducted using the English-language-literature indexed on PubMed and Google Scholar without time limit, supplemented by other sources, including published reviews.

RESULTS

Each treatment recommendation was evaluated with respect to the strength of evidence for its efficacy, safety, tolerability, and feasibility. Psychoeducation and psychotherapy are first-choice treatments and should always be conducted. The type of medication recommended depended mainly on the intensity of CSBD and comorbid sexual and psychiatric disorders. There are few randomised controlled trials. Although no medications carry formal indications for CSBD, selective-serotonin-reuptake-inhibitors and naltrexone currently constitute the most relevant pharmacological treatments for the treatment of CSBD. In cases of CSBD with comorbid paraphilic disorders, hormonal agents may be indicated, and one should refer to previously published guidelines on the treatment of adults with paraphilic disorders. Specific recommendations are also proposed in case of chemsex behaviour associated with CSBD.

CONCLUSIONS

An algorithm is proposed with different levels of treatment for different categories of patients with CSBD.

Advances in problematic usage of the internet research - A narrative review by experts from the European network for problematic usage of the internet

Global concern about problematic usage of the internet (PUI), and its public health and societal costs, continues to grow, sharpened in focus under the privations of the COVID-19 pandemic. This narrative review reports the expert opinions of members of the largest international network of researchers on PUI in the framework of the European Cooperation in Science and Technology (COST) Action (CA 16207), on the scientific progress made and the critical knowledge gaps remaining to be filled as the term of the Action reaches its conclusion. A key advance has been achieving consensus on the clinical definition of various forms of PUI. Based on the overarching public health principles of protecting individuals and the public from harm and promoting the highest attainable standard of health, the World Health Organisation has introduced several new structured diagnoses into the ICD-11, including gambling disorder, gaming disorder, compulsive sexual behaviour disorder, and other unspecified or specified disorders due to addictive behaviours, alongside naming online activity as a diagnostic specifier. These definitions provide for the first time a sound platform for developing systematic networked research into various forms of PUI at global scale. Progress has also been made in areas such as refining and simplifying some of the available assessment instruments, clarifying the underpinning brain-based and social determinants, and building more empirically based etiological models, as a basis for therapeutic intervention, alongside public engagement initiatives. However, important gaps in our knowledge remain to be tackled. Principal among these include a better understanding of the course and evolution of the PUI-related problems, across different age groups, genders and other specific vulnerable groups, reliable methods for early identification of individuals at risk (before PUI becomes disordered), efficacious preventative and therapeutic interventions and ethical health and social policy changes that adequately safeguard human digital rights. The paper concludes with recommendations for achievable research goals, based on longitudinal analysis of a large multinational cohort co-designed with public stakeholders.

Considering gender differences in the study and treatment of internet gaming disorder

BACKGROUND AND AIMS

Internet gaming disorder (IGD) is a multifaceted and complex addictive disorder characterized by poor impulse control and altered reward sensitivities, among other features. IGD is a male-predominant condition, and gender-related differences may contribute importantly to the development and maintenance of, and recovery from, IGD.

METHODS

The current manuscript proposes a framework that incorporates gender-related considerations at different stages of IGD and proposes potential strategies for the prevention and treatment of IGD.

RESULTS

At the development stage, high impulsivity, impaired inhibitory control, and aggressive behaviors have been more frequently observed among males than females, suggesting potential risk factors for the development of IGD. Loneliness and other emotional dysregulation have been more frequently noted among females (than among males) with IGD. At the maintenance stage, males may be more sensitive to gaming-related rewards than females, and acute gaming behaviors may elicit higher cravings among males than among females and thus weaken their inhibitory control. In recovery, females with IGD have reported more negative mood states than males, and females' gaming behaviors have been linked with affective disorders.

DISCUSSIONS

The model proposed here highlights gender-related differences in modulating the behavioral and neural systems that contribute to a three-stage framework of IGD. Additional investigation into gender-related differences in IGD may further advance the field by uncovering complex relationships that may underlie vulnerability and provide insights into the development of gender-specific prevention and treatment strategies.

Exploring Internet gaming disorder: an updated perspective of empirical evidence (from 2016 to 2021)

BACKGROUND AND AIMS

Since the acceptance of Internet gaming disorder (IGD) as a "disorder due to addictive behaviors", research has proliferated exponentially. The present review focuses on the conceptualization of IGD, its diagnosis and assessment, associated factors and existing prevention and treatment plans to address it.

RESULTS AND CONCLUSIONS

The discrepancies between the diagnostic criteria for IGD proposed by the two central diagnostic entities, as well as the questioning of their clinical validity, have generated multiple proposals for the diagnosis and psychometric evaluation of IGD. Likewise, there have been numerous suggestions to prevent this pathology, with the involvement of governments, the gaming industry and health institutions. Finally, multiple treatment plans have been proposed, both pharmacological and psychological, although only the efficacy of cognitive behavioral therapy has been tested. It is essential, therefore, to delve deeper into this disorder by addressing the central limitations of the current literature.

The Effect of Non-Invasive Brain Stimulation on the Downregulation of Negative Emotions: A Meta-Analysis

(1) Background: Emotion regulation (ER) is regarded as a core treatment target for depression and other mental illnesses. In recent years, non-invasive brain stimulation (NIBS) has been extensively used as an intervention for mental illnesses, but there has been no systematic review conducted regarding its effect on emotion regulation. Therefore, we conducted a meta-analysis of the effectiveness of NIBS for emotion regulation; (2) Methods: Systematic searches were conducted in Embase, Web of Science, PubMed, and Cochrane Library. We analyzed the effects of NIBS on tasks assessing emotion regulation using a random-effects model, and further explored the moderating role of the following factors on transcranial direct current stimulation (tDCS) studies by conducting subgroup analyses and meta-regression: target electrode placement, return electrode placement, current intensity, target electrode size, and duration of intervention; (3) Results: A total of 17 studies were included. Our meta-analysis indicated a small but significant effect of NIBS on the downregulation of negative emotions. Separate analyses indicated that repetitive transcranial magnetic stimulation (rTMS) had a medium and significant effect on the downregulation of negative emotions, whereas tDCS had no significant effect. Subgroup analyses showed that the effect of tDCS was moderated by target and return electrode placemen; (4) Conclusions: These results indicate that NIBS had a positive effect on the downregulation of negative emotions. The stimulation protocols should be carefully considered and the underlying mechanisms should be further explored.

Transcranial Direct Current Stimulation of the Dorsolateral Prefrontal Cortex for Treatment of Neuropsychiatric Disorders

Background

The dorsolateral prefrontal cortex (DLPFC) is a key node of the frontal cognitive circuit. It is involved in executive control and many cognitive processes. Abnormal activities of DLPFC are likely associated with many psychiatric diseases. Modulation of DLPFC may have potential beneficial effects in many neural and psychiatric diseases. One of the widely used non-invasive neuromodulation technique is called transcranial direct current stimulation (or tDCS), which is a portable and affordable brain stimulation approach that uses direct electrical currents to modulate brain functions.

Objective

This review aims to discuss the results from the past two decades which have shown that tDCS can relieve clinical symptoms in various neurological and psychiatric diseases.

Methods

Here, we performed searches on PubMed to collect clinical and preclinical studies that using tDCS as neuromodulation technique, DLPFC as the stimulation target in treating neuropsychiatric disorders. We summarized the stimulation sites, stimulation parameters, and the overall effects in these studies.

Results

Overall, tDCS stimulation of DLPFC could alleviate the clinical symptoms of schizophrenia, depression, drug addiction, attention deficit hyperactivity disorder and other mental disorders.

Conclusion

The stimulation parameters used in these studies were different from each other. The lasting effect of stimulation was also not consistent. Nevertheless, DLPFC is a promising target for non-invasive stimulation in many psychiatric disorders. TDCS is a safe and affordable neuromodulation approach that has potential clinical uses. Larger clinical studies will be needed to determine the optimal stimulation parameters in each condition.

Altered effective connectivity from the pregenual anterior cingulate cortex to the laterobasal amygdala mediates the relationship between internet gaming disorder and loneliness

BACKGROUND

Individual with internet gaming disorder (IGD) often experience a high level of loneliness, and neuroimaging studies have demonstrated that amygdala function is associated with both IGD and loneliness. However, the neurobiological basis underlying these relationships remains unclear.

METHODS

In the current study, Granger causal analysis was performed to investigate amygdalar subdivision-based resting-state effective connectivity differences between 111 IGD subjects and 120 matched participants with recreational game use (RGUs). We further correlated neuroimaging findings with clinical measures. Mediation analysis was conducted to explore whether amygdalar subdivision-based effective connectivity mediated the relationship between IGD severity and loneliness.

RESULTS

Compared with RGUs, IGD subjects showed inhibitory effective connections from the left pregenual anterior cingulate cortex (pACC) to the left laterobasal amygdala (LBA) and from the right medial prefrontal cortex (mPFC) to the left LBA, as well as an excitatory effective connection from the left middle prefrontal gyrus (MFG) to the right superficial amygdala. Further analyses demonstrated that the left pACC-left LBA effective connection was negatively correlated with both Internet Addiction Test and UCLA Loneliness scores, and it mediated the relationship between the two.

CONCLUSION

IGD subjects and RGUs showed different connectivity patterns involving amygdalar subdivisions. These findings support a neurobiological mechanism for the relationship between IGD and loneliness, and suggest targets for therapeutic approaches that could be used to treat IGD.

Comparison of frontostriatal circuits in adolescent nicotine addiction and internet gaming disorder

BACKGROUND

Recently, there has been significantly increased participation in online gaming and other addictive behaviors particularly in adolescents. Tendencies to avoid social interaction and become more involved in technology-based activities pose the danger of creating unhealthy addictions. Thus, the presence of relatively immature cognitive control and high risk-taking properties makes adolescence a period of major changes leading to an increased rate of emotional disorders and addiction.

AIMS

The critical roles of frontostriatal circuits in addiction have become the primary focus associated with reward in the striatum and cognitive control in the PFC. Internet gaming disorder (IGD) and nicotine addiction are currently becoming more and more serious.

METHODS

In the light of neuroimaging, the similarity between brain mechanisms causing substance use disorder (SUD) and IGD have been described in previous literature.

RESULTS

In particular, two distinct brain systems affect the way we act accounting for uncharacteristic neural function in addiction: the affective system comprises of the striatum driven by emotional, reward-related, and internal stimuli, and a cognitive system consisting of the prefrontal cortex (PFC) supporting the ventral affective system's actions via inhibitory control.

DISCUSSION AND CONCLUSION

Therefore, as a novel concept, we focused on the implication of frontostriatal circuits in nicotine addiction and IGD by reviewing the main findings from our studies compared to those of others. We hope that all of these neuroimaging findings can lead to effective intervention and treatment for addiction especially during this critical period.

How Theoretical Models Can Inspire Advances in Research and Clinical Practice: The Example of Behavioral Addictions

Abstract. Aims: In this narrative position paper, we will summarize some examples of theoretical models of behavioral addictions. We will then make some suggestions for how theoretical models may inspire both research and clinical practice in the context of behavioral addictions. Results: Current theoretical models typically distinguish between general and specific risk factors. It is commonly argued that based on conditioning processes, affective responses to specific stimuli (cue-reactivity and craving) develop within the course of behavioral addictions. Diminished control over the behavior is reflected in reductions in inhibitory control and executive functioning. Cognitive distortions, attentional biases, and behavior-related expectancies are also considerable mechanisms. Theoretical models have been used to inspire advances not only in research but also in clinical practice. For example, theoretical models have inspired the development of standardized treatment protocols. Conclusions: If theoretical models contributed more consistently to scientific studies, a better understanding of the processes underlying specific mental disorders could be facilitated, which could then promote updates and modifications of the theoretical models and improvements in clinical practice. Close connections and stimulating discussions between theorists and therapists are very important and beneficial for advances over time.

Large-scale network dysfunction in youths with Internet gaming disorder: a meta-analysis of resting-state functional connectivity studies

Internet gaming disorder (IGD) has been defined as a specific behavioral disorder, associated with abnormal interactions among large-scale brain networks. Researchers have sought to identify the network dysfunction in IGD using resting-state functional connectivity (rsFC). However, results across studies have not reached an agreement yet and the mechanism remains unclear. The present research aimed to investigate network dysfunction in IGD through a meta-analysis of rsFC studies. Twenty-two seed-based voxel-wise rsFC studies from 25 publications (594 individuals with IGD and 496 healthy controls) were included. By categorizing seeds into seed-networks based on their location within a prior functional network parcellations, we performed a Multilevel kernel density analysis (MKDA) within each seed-network to identify which brain systems showed abnormal interaction with particular seed-network in individuals with IGD. Compared to healthy control groups, individuals with IGD exhibited significant hypoconnectivity within the default mode network, and enhanced connectivity between the default mode network and insula within the ventral attention network. IGD was also associated with increased connectivity between the ventral attention network and somatomotor regions. Furthermore, the IGD groups showed hyperconnectivity between the limbic network and regions of the frontoparietal network. The results suggest that individuals with IGD show large-scale functional network alteration which underpins their core symptoms including poor emotional competence, cue-reactivity and craving, habitual addictive behaviors and impaired executive control. Whether the compensation mechanism exists in IGD is discussed, and further research is needed. The findings provide a neurocognitive network model of IGD, which may serve as functional biomarkers for IGD and have potentials for development of effective diagnosis and therapeutic interventions.

Can pharmacotherapy improve treatment outcomes in people with co-occurring major depressive and cocaine use disorders?

Introduction: Major depressive disorder (MDD) and cocaine use disorder (CUD) are prevalent and frequently co-occur. When co-occurring, the presence of one disorder typically negatively impacts the prognosis for the other. Given the clinical relevance, we sought to examine pharmacotherapies for co-occurring CUD and MDD. While multiple treatment options have been examined in the treatment of each condition individually, studies exploring pharmacological options for their comorbidity are fewer and not conclusive.Areas Covered: For this review, the authors searched the literature in PubMed using clinical query options for therapies and keywords relating to each condition. Then, they described potentially promising pharmacologic therapeutic options based on shared mechanisms between the two conditions and/or results from individual clinical trials conducted to date.Expert opinion: Medications like stimulants, dopamine (D3) receptors partial agonists or antagonists, antagonists of kappa opioid receptors, topiramate, and ketamine could be promising as there is significant overlap relating to reward deficiency models, antireward pathways, and altered glutamatergic systems. However, the available clinical literature on any one of these types of agents is mixed. Additionally, for some agents there is possible concern related to abuse potential (e.g. ketamine and stimulants).

Impaired Learning From Errors and Punishments and Maladaptive Avoidance-General Mechanisms Underlying Self-Regulation Disorders?

Self-regulation (SR) is an important human function that relates to quality of life in multiple domains including mental health. Previous studies have found important correlates of low SR including impulsivity and poor emotional regulation; however, underpinnings of low SR are incompletely understood. Individuals low in SR frequently engage in maladaptive behaviors (substance abuse, procrastination, etc.) despite negative consequences. This phenomenon suggests that impaired learning from errors and punishments may be important mechanisms underlying low SR. Consistently, previous studies observed impaired error processing in a wide spectrum of individuals with low SR and impaired learning from errors and punishments in SR-related disorders. We also note a possible role for poor emotional regulation and refer to concepts suggesting that engaging in maladaptive behaviors may serve as short term emotion regulation strategies aimed at avoiding or alleviating negative affect. We speculate on transdiagnostic factors underlying poor SR. We propose that impaired error processing (possibly related to striatal functioning) may prevent subjects with low SR from learning from errors and punishments and thus learning better SR skills or tendencies. Additionally, impaired coping in emotionally challenging situations, possibly related to prefrontal-cortical functioning, may lead to maladaptive avoidance. Moreover, maladaptive behaviors may be reinforced by the temporary decreases in negative affect and rewarding values of behaviors. Given existing knowledge gaps, we call for more extensive research and describe possible directions and challenges for future studies.