Background: Internet gaming disorder (IGD) is a type of behavioural addictions. One of the key features of addiction is the excessive exposure to addictive objectives (e.g. drugs) reduces the sensitivity of the brain reward system to daily rewards (e.g. money). This is thought to be mediated via the signals expressed as dopaminergic reward prediction error (RPE). Emerging evidence highlights blunted RPE signals in drug addictions. However, no study has examined whether IGD also involves alterations in RPE signals that are observed in other types of addictions.Methods: To fill this gap, we used functional magnetic resonance imaging data from 45 IGD and 42 healthy controls (HCs) during a reward-related prediction-error task and utilised a psychophysiological interaction (PPI) analysis to characterise the underlying neural correlates of RPE and related functional connectivity.Results: Relative to HCs, IGD individuals showed impaired reinforcement learning, blunted RPE signals in multiple regions of the brain reward system, including the right caudate, left orbitofrontal cortex (OFC), and right dorsolateral prefrontal cortex (DLPFC). Moreover, the PPI analysis revealed a pattern of hyperconnectivity between the right caudate, right putamen, bilateral DLPFC, and right dorsal anterior cingulate cortex (dACC) in the IGD group. Finally, linear regression suggested that the connection between the right DLPFC and right dACC could significantly predict the variation of RPE signals in the left OFC.Conclusions: These results highlight disrupted RPE signalling and hyperconnectivity between regions of the brain reward system in IGD. Reinforcement learning deficits may be crucial underlying characteristics of IGD pathophysiology.

Character strengths could effectively prevent negative psychological outcomes in adults. However, there was little research conducted among early adolescents. The present study aimed to explore character strengths that were independently related to fewer behavior problems in early adolescents. In total, 521 early adolescents (mean age 10.92 ± 0.04, range 10–12 years) were recruited from primary schools in Sichuan, China. Character strengths were measured using the Values in Action Inventory of Strengths for Youth (VIA-Youth). Behavior problems were measured using the Conners Parent Symptom Questionnaire (PSQ). The results showed that behavior problems were negatively correlated with character strengths (r= −0.14 to −0.3,p< 0.05 Bonferroni corrected). Character strengths explained a significant proportion of additional variance (14–22%) in five types of behavior problems after controlling the effect of demographic factors (residence, left-behind experiences, maternal education level). Moreover, several specific character strengths showed an independent contribution (β= −0.34 to −0.14 for self-regulation, perseverance, zest, humility, and leadership;β= 0.21 to 0.34, for hope; allp< 0.05) to behavior problems. Our study revealed that character strengths were protective factors against behavior problems in early adolescents.

Suicidal ideation (SI) and suicide attempts (SA) are highly prevalent in individuals with major depressive disorder (MDD). To explore the structural and functional neural changes associated with SI and SA, we analyzed multimodal Magnetic Resonance Imaging (MRI) data from 159 participants, including those with MDD with suicide attempts (SA group, n = 34), those with MDD with suicidal ideation but not attempts (SI group, n = 53), those with MDD without suicidal ideation (NSI group, n = 14), and healthy controls (HC, n = 59). Voxel-based morphometry (VBM) analysis was performed to estimate and compare gray matter volume (GMV) across groups. Subsequently, a seed-based resting-state functional connectivity (rsFC) analysis was conducted to explore the functional networks associated with the structural brain changes related to suicidal ideation and suicide attempts. Compared with the HC and NSI groups, the SI group showed decreased GMV in the left dorsolateral prefrontal cortex (DLPFC), insula, fusiform gyrus, right posterior cerebellum, and right middle temporal gyrus. Additionally, when compared to the HC and SI groups, the SA group demonstrated smaller GMV in the right superior medial frontal gyrus (SFGmed), left superior and inferior occipital gyri, and superior temporal gyrus (STG), and right cuneus, but larger GMV in the right STG. Moreover, GMV in the insula, cerebellum posterior lobe, and SFGmed was negatively correlated with the scores of the Beck Scale for Suicide Ideation (BSSI). The rsFC analysis revealed weaker rsFC between the left insula and the left SFG as well as between the bilateral middle frontal orbital gyrus and the right SFGmed and the left middle occipital gyrus, but stronger rsFC of the right cerebellum posterior lobe with the left precentral gyrus and right parahippocampal gyrus among the SI group compared to the NSI group and HCs. Additionally, the SA group demonstrated weaker rsFC between the right cerebellum posterior lobe and the left cerebellum posterior lobe as well as the right lingual gyrus, but stronger rsFC between the right SFGmed and the left middle temporal gyrus and right inferior parietal lobule compared to the SI group. Our results indicate that structural and functional changes related to insula, DLPFC and cerebellum posterior lobe are associated with the generation and escalation of SI in MDD, while the structural and functional changes related to SFGmed and STG play a crucial role in the transformation from SI to SA in MDD.

Background and aims: The Pavlovian-to-instrumental transfer (PIT) effect is a phenomenon that Pavlovian conditioned cues that could influence one's instrumental behavior. In several substance and behavioral addictions, such as tobacco use disorder and gambling disorder, addiction-related cues could promote independently trained instrumental drug-seeking/drug-taking behaviors, indicating a specific PIT effect. However, it is unclear whether Internet gaming disorder (IGD) would show a similar change in PIT effects as other addictions. The study aimed to explore the specific PIT effects in IGD.Methods: We administrated a PIT task to individuals with IGD (n = 40) and matched health controls (HCs, n = 50), and compared the magnitude of specific PIT effects between the two groups. The severity of the IGD symptoms was assessed by the Chinese version 9-item Internet Gaming Disorder Scale (IGDS) and the Internet Addiction Test (IAT).Results: We found that: (1) related to the HCs group, the IGD group showed enhanced specific PIT_game effects, where gaming-related cues lead to an increased choice rate of gaming-related responses; (2) in the IGD group, the magnitude of specific PIT_game effects were positively correlated with IAT scores (rho = 0.39, p = 0.014).Discussion and Conclusions: Individuals with IGD showed enhanced specific PIT effects related to HCs, which were associated with the severity of addictive symptoms. Our results highlighted the incentive salience of gaming-related cues in IGD.

The death/suicide implicit association test (IAT) may be more resilient to accurately assess suicide risk than self-reports. We examined the IAT in 130 patients with depression and 125 healthy controls, along with self-reported suicidal ideation. IAT could differentiate patients with suicide attempts from patients without suicide attempts and controls. IAT measures were significantly correlated to explicit suicidal ideation and clinical symptoms in patients. Moreover, the IAT-symptom correlations were significant in female but not male patients. The IAT showed promise as a valid tool to estimate suicide risk in patients with depression and may be particularly useful in female patients.