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Aims: To identify subgroups of people with internet gaming disorder (IGD) based on addiction‐related resting‐state functional connectivity and how these subgroups show different clinical correlates and responses to treatment. Design: Secondary analysis of two functional magnetic resonance imaging (fMRI) data sets. Setting: Zhejiang province and Beijing, China. Participants: One hundred and sixty‐nine IGD and 147 control subjects. Measurements k‐Means algorithmic and support‐vector machine‐learning approaches were used to identify subgroups of IGD subjects. These groups were examined with respect to assessments of craving, behavioral activation and inhibition, emotional regulation, cue–reactivity and guessing‐related measures. Findings Two groups of subjects with IGD were identified and defined by distinct patterns of connectivity in brain networks previously implicated in addictions: subgroup 1 ('craving‐related subgroup') and subgroup 2 ('mixed psychological subgroup'). Clustering IGD on this basis enabled the development of diagnostic classifiers with high sensitivity and specificity for IGD subgroups in 10‐fold validation (n = 218) and out‐of‐sample replication (n = 98) data sets. Subgroup 1 is characterized by high craving scores, cue–reactivity during fMRI and responsiveness to a craving behavioral intervention therapy. Subgroup 2 is characterized by high craving, behavioral inhibition and activations scores, non‐adaptive emotion‐regulation strategies and guessing‐task fMRI measures. Subgroups 1 and 2 showed largely opposite functional–connectivity patterns in overlapping networks. Conclusions: There appear to be two subgroups of people with internet gaming disorder, each associated with differing patterns of brain functional connectivity and distinct clinical symptom profiles and gender compositions. [ABSTRACT FROM AUTHOR]

Alterations in brain connectivity have been implicated in internet gaming disorder (IGD). However, little is known about alterations in whole-brain connectivity and their associations with long-term treatment outcomes. Here, we used a relatively new analytic approach, intrinsic connectivity distribution (ICD) analysis, to examine brain connectivity in 74 IGD participants and 41 matched healthy controls (HCs) and conducted post hoc seed-based resting-state functional connectivity (rsFC) analyses based on the ICD findings. We also examined how these findings related to outcomes involving a craving behavioral intervention (CBI) for IGD. IGD participants showed less whole-brain connectivity in the left angular gyrus and ventromedial prefrontal cortex (vmPFC) compared with HC participants. Seed-based rsFC analyses revealed that the left angular gyrus in the IGD group showed less connectivity with areas involved in the default-mode network and greater connectivity with areas in the salience and executive control networks. CBI was associated with improved connectivity within regions in the default-mode network and regions across the default-mode and salience networks. ICD-identified connectivity differences in the left angular gyrus and vmPFC were related to changes in craving and severity of addiction 6 months after the intervention. The findings suggest that IGD is associated with alterations in brain connectivity that may be sensitive to interventions. Thus, the findings have implications for understanding mechanisms underlying CBI effects and for further treatment development. [ABSTRACT FROM AUTHOR]

Aims: To estimate the aggregated effect sizes of reward‐related decision‐making deficits in internet gaming disorder (IGD) and to explore potential moderators on the variability of effect sizes across studies. Design Review of peer‐reviewed studies comparing reward‐related decision‐making performance between IGD and control participants identified via PubMed, Web of Science and ProQuest databases. Random‐effects modeling was conducted using Hedge's g as the effect size (ES). The effects of decision‐making situation, valence, sample type, testing environment, IGD severity and self‐reported impulsivity on decision‐making differences were examined by moderator analyses. Setting: No restrictions on location. Participants: Twenty‐four studies (20 independent samples) were included in the meta‐analysis, resulting in 604 IGD and 641 control participants and 35 ESs. Measures Reward‐related decision‐making differences between IGD and control groups. Findings The overall ES for decision‐making deficits in IGD was small (g = −0.45, P < 0.01). The effects were comparable across risky, ambiguous and inter‐temporal decision‐making. Larger aggregate ESs were identified for pure‐gain and mixed compared with pure‐loss decision‐making. Studies based on clinical and community samples showed similar effects. No significant difference between behavioral studies and those with extra measurements was observed. Decision‐making alterations were not closely associated with IGD severity or self‐reported impulsivity differences at the study level. Conclusions: Internet gaming disorder appears to be consistently associated with reward‐related decision‐making deficits. [ABSTRACT FROM AUTHOR]

Internet gaming disorder (IGD), a worldwide mental health issue, has been widely studied using neuroimaging techniques during the last decade. Although dysfunctions in resting‐state functional connectivity have been reported in IGD, mapping relationships from abnormal connectivity patterns to behavioral measures have not been fully investigated. Connectome‐based predictive modeling (CPM)—a recently developed machine‐learning approach—has been used to examine potential neural mechanisms in addictions and other psychiatric disorders. To identify the resting‐state connections associated with IGD, we modified the CPM approach by replacing its core learning algorithm with a support vector machine. Resting‐state functional magnetic resonance imaging (fMRI) data were acquired in 72 individuals with IGD and 41 healthy comparison participants. The modified CPM was conducted with respect to classification and regression. A comparison of whole‐brain and network‐based analyses showed that the default‐mode network (DMN) is the most informative network in predicting IGD both in classification (individual identification accuracy = 78.76%) and regression (correspondence between predicted and actual psychometric scale score: r = 0.44, P < 0.001). To facilitate the characterization of the aberrant resting‐state activity in the DMN, the identified networks have been mapped into a three‐subsystem division of the DMN. Results suggest that individual differences in DMN function at rest could advance our understanding of IGD and variability in disorder etiology and intervention outcomes. [ABSTRACT FROM AUTHOR]

Understanding the neural mechanisms underlying Internet gaming disorder (IGD) is essential for the condition's diagnosis and treatment. Nevertheless, the pathological mechanisms of IGD remain elusive at present. Hence, we employed multi-voxel pattern analysis (MVPA) and spectral dynamic causal modeling (spDCM) to explore this issue. Resting-state fMRI data were collected from 103 IGD subjects (male = 57) and 99 well-matched recreational game users (RGUs, male = 51). Regional homogeneity was calculated as the feature for MVPA based on the support vector machine (SVM) with leave-one- out cross-validation. Mean time series data extracted from the brain regions in accordance with the MVPA results were used for further spDCM analysis. Results display a high accuracy of 82.67% (sensitivity of 83.50% and specificity of 81.82%) in the classification of the two groups. The most discriminative brain regions that contributed to the classification were the bilateral parahippocampal gyrus (PG), right anterior cingulate cortex (ACC), and middle frontal gyrus (MFG). Significant correlations were found between addiction severity (IAT and DSM scores) and the ReHo values of the brain regions that contributed to the classification. Moreover, the results of spDCM showed that compared with RGU, IGD showed decreased effective connectivity from the left PG to the right MFG and from the right PG to the ACC and decreased self-connection in the right PG. These results show that the weakening of the PG and its connection with the prefrontal cortex, including the ACC and MFG, may be an underlying mechanism of IGD. [ABSTRACT FROM AUTHOR]

Psychobehavioral intervention is an effective treatment of Internet addiction, including Internet gaming disorder (IGD). However, the neural mechanisms underlying its efficacy remain unclear. Cortical-ventral striatum (VS) circuitry is a common target of psychobehavioral interventions in drug addiction, and cortical-VS dysfunction has been reported in IGD; hence, the primary aim of the study was to investigate how the VS circuitry responds to psychobehavioral interventions in IGD. In a cross-sectional study, we examined resting-state functional connectivity of the VS in 74 IGD subjects (IGDs) and 41 healthy controls (HCs). In a follow-up craving behavioral intervention (CBI) study, of the 74 IGD subjects, 20 IGD subjects received CBI (CBI+) and 16 IGD subjects did not (CBI-). All participants were scanned twice with similar time interval to assess the effects of CBI. IGD subjects showed greater resting-state functional connectivity of the VS to left inferior parietal lobule (lIPL), right inferior frontal gyrus and left middle frontal gyrus, in positive association with the severity of IGD. Moreover, compared with CBI-, CBI+ showed significantly greater decrease in VS-lIPL connectivity, along with amelioration in addiction severity following the intervention. These findings demonstrated that functional connectivity between VS and lIPL, each presumably mediating gaming craving and attentional bias, may be a potential biomarker of the efficacy of psychobehavioral intervention. These results also suggested that non-invasive techniques such as transcranial magnetic or direct current stimulation targeting the VS-IPL circuitry may be used in the treatment of Internet gaming disorders. [ABSTRACT FROM AUTHOR]

Cue-induced brain reactivity has been suggested to be a fundamental and important mechanism explaining the development, maintenance, and relapse of addiction, including Internet gaming disorder (IGD). Altered activity in addiction-related brain regions has been found during cue-reactivity in IGD using functional magnetic resonance imaging (fMRI), but less is known regarding the alterations of coordinated whole brain activity patterns in IGD. To investigate the activity of temporally coherent, large-scale functional brain networks (FNs) during cue-reactivity in IGD, independent component analysis was applied to fMRI data from 29 male subjects with IGD and 23 matched healthy controls (HC) performing a cue-reactivity task involving Internet gaming stimuli (i.e., game cues) and general Internet surfing-related stimuli (i.e., control cues). Four FNs were identified that were related to the response to game cues relative to control cues and that showed altered engagement/disengagement in IGD compared with HC. These FNs included temporo-occipital and temporo-insula networks associated with sensory processing, a frontoparietal network involved in memory and executive functioning, and a dorsal-limbic network implicated in reward and motivation processing. Within IGD, game versus control engagement of the temporo-occipital and frontoparietal networks were positively correlated with IGD severity. Similarly, disengagement of temporo-insula network was negatively correlated with higher game-craving. These findings are consistent with altered cue-reactivity brain regions reported in substance-related addictions, providing evidence that IGD may represent a type of addiction. The identification of the networks might shed light on the mechanisms of the cue-induced craving and addictive Internet gaming behaviors. [ABSTRACT FROM AUTHOR]

Internet gaming disorder (IGD) is characterized by cognitive and emotional deficits. Previous studies have reported the co-occurrence of IGD and depression. However, extant brain imaging research has largely focused on cognitive deficits in IGD. Few studies have addressed the comorbidity between IGD and depression symptoms and underlying neural mechanisms. Here, we systematically investigated this issue by combining a longitudinal survey study, a cross-sectional resting-state functional connectivity (rsFC) study and an intervention study. Autoregressive cross-lagged modeling on a longitudinal dataset of college students showed that IGD severity and depression are reciprocally predictive. At the neural level, individuals with IGD exhibited enhanced rsFC between the left amygdala and right dorsolateral prefrontal cortex (DLPFC), inferior frontal and precentral gyrus, compared with control participants, and the amygdala-frontoparietal connectivity at the baseline negatively predicted reduction in depression symptoms following a psychotherapy intervention. Further, following the intervention, individuals with IGD showed decreased connectivity between the left amygdala and left middle frontal and precentral gyrus, as compared with the non-intervention group. These findings together suggest that IGD may be closely associated with depression; aberrant rsFC between emotion and executive control networks may underlie depression and represent a therapeutic target in individuals with IGD. [ABSTRACT FROM AUTHOR]

Studies conducted in drug addiction suggest a transition in processing of drug-related cues from the ventral to the dorsal component of the striatum. However, this process has not been studied in a behavioral addiction. Assessment of this process in a non-drug addiction can provide insight into the pathophysiology of both substance and behavioral addictions. Thirty-nine male Internet gaming disorder (IGD) subjects and 23 male matched healthy controls (HCs) participated in functional magnetic resonance imaging during performance of a cue-reactivity task involving alternating presentation of Internet gaming-related stimuli (game cues) and general Internet surfing-related stimuli (control cues). Cue-induced neural activations in the ventral and dorsal striatum (DS) were compared between IGD and HC participants. Associations between cue-reactivity within these regions and cue-induced craving and severity and duration of IGD were also explored. IGD participants exhibited higher cue-induced activations within both the ventral and DS when compared with HCs. Within the IGD group, activity within the left ventral striatum (VS) was correlated negatively with cue-induced craving; positive associations were found between activations within the DS (right putamen, pallidum and left caudate) and duration of IGD. Cue-induced activity within the left putamen was negatively associated with right VS volumes among IGD participants. Consistent with studies in substance addictions, our results suggest that a transition from ventral to dorsal striatal processing may occur among individuals with IGD, a condition without the impact of substance intake. [ABSTRACT FROM AUTHOR]

The insula has been implicated in salience processing, craving, and interoception, all of which are critical to the clinical manifestations of drug and behavioral addiction. In this functional magnetic resonance imaging (fMRI) study, we examined resting-state functional connectivity (rsFC) of the insula and its association with Internet gaming characteristics in 74 young adults with Internet gaming disorder (IGD) and 41 age- and gender-matched healthy control subjects (HCs). In comparison with HCs, IGD subjects (IGDs) exhibited enhanced rsFC between the anterior insula and a network of regions including anterior cingulate cortex (ACC), putamen, angular gyrus, and precuneous, which are involved in salience, craving, self-monitoring, and attention. IGDs also demonstrated significantly stronger rsFC between the posterior insula and postcentral gyrus, precentral gyrus, supplemental motor area, and superior temporal gyrus (STG), which are involved in interoception, movement control, and auditory processing. Furthermore, IGD severity was positively associated with connectivity between the anterior insula and angular gyrus, and STG, and with connectivity between the posterior insula and STG. Duration of Internet gaming was positively associated with connectivity between the anterior insula and ACC. These findings highlight a key role of the insula in manifestation of the core symptoms of IGD and the importance to examine functional abnormalities of the anterior and posterior insula separately in IGDs. [ABSTRACT FROM AUTHOR]

Individuals with addictions often encounter environmental cues that may trigger repeated engagement in addictive behaviors despite adverse consequences. In substance use disorders, Pavlovian cues may influence instrumental behaviors (Pavlovian-to-instrumental transfer or PIT), and dominant habitual control that is insensitive to outcome values may serve as a foundational mechanism in addiction development. Although existing research suggests learning associations play important roles in internet gaming disorder (IGD), the contributions of PIT effects, habitual control, and connections with behavior remain largely uninvestigated. The present study sought to examine specific transfer effects of monetary cues, general transfer effects of gaming-related cues, and habitual control over instrumental behaviors as reflected in devaluation sensitivity, probing their interrelations and associations with gaming behaviors. Forty-five adults with IGD and 42 adults with recreational game use (RGU) at baseline performed a PIT task with a devaluation procedure. Participants reported gaming behavior and addiction severity at baseline and a four-month follow-up. Results demonstrated (1) a greater specific transfer effect in the IGD group compared to the RGU group; (2) positive correlations between specific and general transfer effects in both groups; (3) specific transfer effects of Go behavior in the IGD group positively correlating with habitual control, and No-Go behavior in the RGU group negatively correlating with habitual control; (4) transfer effects and habitual control relating prospectively to participants' gaming phenotypes at the four-month follow-up. These findings offer early evidence linking Pavlovian and instrumental associations to the development of IGD and suggest potential targets for prevention and intervention strategies. • Understanding cue-triggered biases and habitual control over instrumental behavior in IGD remains insufficient. • Adapted PIT task including specific PIT of monetary and general PIT of gaming cues components, and an outcome devaluation. • Compared with RGU, IGD showed a higher specific PIT effect, and similar general PIT effects and habit control. • The association between specific PIT effects and habit control was reversed between the two groups. • Transfer effects and habitual control were related to participants' gaming phenotypes at the four-month follow-up. [ABSTRACT FROM AUTHOR]

• Internet gaming disorder (IGD) has few empirically validated treatments. • tDCS of the right dlPFC enhanced craving- and negative-emotion-regulation in IGD. • Common substrates underlie reward- and negative-emotion-regulation in IGD. • tDCS may be a promising approach for treating IGD. Reward-seeking and relief from negative emotions are two central motivational drives underlying addictions. Impaired executive control over craving and negative emotions contributes to compulsive addictive behaviors. Neuroimaging evidence has implicated the prefrontal cortex (PFC) in regulating craving or emotions. This study aims at examining whether anodal transcranial direct current stimulation (tDCS) over a specific region of the PFC would enhance both regulation processes. Thirty-three men with internet gaming disorder received active (1.5 mA for 20 minutes) and sham tDCS over the right dorsolateral PFC (dlPFC) one week apart in a randomized order. During each stimulation session, participants regulated craving for gaming during a regulation of craving (ROC) task and negative emotions during an emotion regulation (ER) task using cognitive reappraisal. Subjective ratings of craving and negative emotions and skin conductance responses (SCRs) were recorded. For both craving and negative emotions, tDCS of the right dlPFC facilitated downregulation and upregulation: active relative to sham tDCS decreased ratings (ROC: 95% CI of difference -1.38 to -0.56, p < 0.001; ER: -1.65 to -0.70, p < 0.001) and/or SCRs (ROC: -1.99 to -0.41 μs, p = 0.004) for downregulation, and increased ratings (ROC: 0.24 to 0.82, p = 0.001; ER: 0.26 to 0.72, p < 0.001) for upregulation. These findings provide the first experimental evidence confirming that tDCS of the right dlPFC enhances both craving- and negative-emotion-regulation. This suggests a promising approach for concurrently enhancing executive control over two central motivational drives underlying addictions. [ABSTRACT FROM AUTHOR]

This meta-analytic study aimed to identify the common and specific neural alterations in Internet gaming disorder (IGD) across different domains and modalities. Two separate meta-analyses for functional neural activation and gray-matter volume were conducted. Sub-meta-analyses for the domains of reward, cold-executive, and hot-executive functions were also performed, respectively. IGD subjects, compared with healthy controls, showed: (1) hyperactivation in the anterior and posterior cingulate cortices, caudate, posterior inferior frontal gyrus (IFG), which were mainly associated with studies measuring reward and cold-executive functions; and, (2) hypoactivation in the anterior IFG in relation to hot-executive function, the posterior insula, somatomotor and somatosensory cortices in relation to reward function. Furthermore, IGD subjects showed reduced gray-matter volume in the anterior cingulate, orbitofrontal, dorsolateral prefrontal, and premotor cortices. These findings suggest that IGD is associated with both functional and structural neural alterations in fronto-striatal and fronto-cingulate regions. Moreover, multi-domain assessments capture different aspects of neural alterations in IGD, which may be helpful for developing effective interventions targeting specific functions. [ABSTRACT FROM AUTHOR]

Abnormal interactions among addiction brain networks associated with intoxication, negative affect, and anticipation may have relevance for internet gaming disorder (IGD). Despite prior studies having identified gender-related differences in the neural correlates of IGD, gender-related differences in the involvement of brain networks remain unclear. One-hundred-and-nine individuals with IGD (54 males) and 111 with recreational game use (RGU; 58 males) provided resting-state fMRI data. We examined gender-related differences in involvement of addiction brain networks in IGD versus RGU subjects. We further compared the strength between and within addiction brain networks and explored possible relationships between the strength of functional connectivities within and between addiction brain networks and several relevant behavioral measures. The addiction brain networks showed high correct classification rates in distinguishing IGD and RGU subjects in men and women. Male subjects with versus without IGD showed stronger functional connectivities between and within addiction brain networks. Moreover, the strength of the connectivity within the anticipation network in male IGD subjects was positively related to subjective craving. However, female subjects with versus without IGD showed decreased functional connections between and within addiction brain networks. The strength of connectivity between the anticipation and negative-affect brain networks in female IGD subjects was negatively related to maladaptive cognitive emotion-regulation strategies. Addiction brain networks have potential for distinguishing IGD and RGU individuals. Importantly, this study identified novel gender-related differences in brain-behavior relationships in IGD. These results help advance current neuroscientific theories of IGD and may inform gender-informed treatment strategies. • Identified novel gender-related brain mechanisms in IGD. • Behavioral measures/correlates differed between male and female IGD subjects. • Addiction brain networks have potential for distinguishing IGD and RGU individuals. [ABSTRACT FROM AUTHOR]

A growing body of evidence indicates that both inhibition and decision-making deficits play essential roles in the development and maintenance of Internet gaming disorder (IGD). Clarifying whether impaired decision-making among individuals with IGD is related to poor inhibition will advance our understanding of IGD and contribute to intervention development. However, the relationship between these two functions remains unclear. In this study, we sought to systemically examine inhibitory processes, decision-making and the relationship between the two among individuals with IGD. Thirty-four individuals with IGD and 32 matched healthy controls (HCs) were recruited. In comparison to HCs, IGD subjects demonstrated inhibition deficits during performance of the gaming-related Go/No-Go task and impaired decision-making under risk. In addition, errors on No-Go trials during the gaming-related Go/No-Go task were positively associated with decision-making impairments under risk but not under ambiguity among IGD subjects. These results suggest individuals with IGD are impaired in some aspects of inhibition and decision-making functions, and that decision-making deficits under risk are linked to poor inhibition specifically related to gaming cues, which has implications for the development of novel intervention. [ABSTRACT FROM AUTHOR]