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.

Efficacy of Transcranial Direct Current Stimulation for Controlling of Food Craving in Subjects With Overweight or Obesity: A Pilot Study.

OBJECTIVE: We aim to explore the effects of transcranial direct current stimulation (tDCS) on food craving improvement and changes in brain function associated with craving by conducting a total of 10 sessions of tDCS over a period of 2 weeks on overweight and obese subjects. METHODS: A total of 15 patients who were overweight or obese (body mass index [BMI] ≥23 kg/m2) were included. Weight, BMI, neuropsychological variables, and food craving-related variables were assessed. We measured absolute and relative power in 19 channels and analyzed quantitative electroencephalography (qEEG) according to the following frequency ranges: delta (1-4 Hz), theta (4-8 Hz), alpha (8-12 Hz), beta (12-25 Hz), high beta (25-30 Hz), and gamma (30-80 Hz). RESULTS: After the application of tDCS, there was no significant reduction observed in weight and BMI. However, all measures related to food and eating showed a decrease in the intensity of cravings, and there was also a significant reduction in depression, anxiety, and perceived stress. In qEEG analysis, an increase in theta waves was observed in the left frontal area (F7 and F3), an increase in alpha waves in the right parietal area (P4), and a decrease in beta waves in the frontal area (FP2) and occipital area (O1). CONCLUSION: This study confirmed the beneficial effects of tDCS on food craving regulation in overweight or obese individuals and observed improved scores in psychological factors such as depression and anxiety. Furthermore, neurophysiological changes related to food craving were observed using qEEG.

Evaluation and Treatment of Obesity and Its Comorbidities: 2022 Update of Clinical Practice Guidelines for Obesity by the Korean Society for the Study of Obesity.

The goal of the 8th edition of the Clinical Practice Guidelines for Obesity is to help primary care physician provide safe, effective care to patients with obesity by offering evidence-based recommendations to improve the quality of treatment. The Committee for Clinical Practice Guidelines comprised individuals with multidisciplinary expertise in obesity management. A steering board of seven experts oversaw the entire project. Recommendations were developed as the answers to key questions formulated in patient/problem, intervention, comparison, outcomes (PICO) format. Guidelines underwent multi-level review and cross-checking and received endorsement from relevant scientific societies. This edition of the guidelines includes criteria for diagnosing obesity, abdominal obesity, and metabolic syndrome; evaluation of obesity and its complications; weight loss goals; and treatment options such as diet, exercise, behavioral therapy, pharmacotherapy, and bariatric and metabolic surgery for Korean people with obesity. Compared to the previous edition of the guidelines, the current edition includes five new topics to keep up with the constantly evolving field of obesity: diagnosis of obesity, obesity in women, obesity in patients with mental illness, weight maintenance after weight loss, and the use of information and communication technology-based interventions for obesity treatment. This edition of the guidelines features has improved organization, more clearly linking key questions in PICO format to recommendations and key references. We are confident that these new Clinical Practice Guidelines for Obesity will be a valuable resource for all healthcare professionals as they describe the most current and evidence-based treatment options for obesity in a well-organized format.

The Mediating Effect of Psychological Distress on the Association between BDNF, 5-HTTLPR, and Tinnitus Severity.

OBJECTIVE: To investigate the association between genetic polymorphisms of brain-derived neurotrophic factor (BDNF) or serotonin transporter gene-linked polymorphic region (5-HTTLPR) and tinnitus, and the mediating effects of psychological distress on this association. METHODS: Eighty-six patients experiencing tinnitus and 252 controls were recruited. The Tinnitus Handicap Inventory was used to assess the severity of tinnitus and the Beck Depression Inventory-II (BDI-II), Beck Anxiety Inventory-II (BAI-II), and the Korean version of the Brief Encounter Psychosocial Instrument (BEPSI-K) were used to assess psychological distress. We compared the association of BDNF rs6265 (Val66Met) and 5-HTTLPR variants in the two groups. The mediating effects of BDI-II, BAI-II, and BEPSI-K were examined using multiple regression analysis and validated by the Sobel test and bootstrapping. RESULTS: No significant differences were found between the groups regarding BDNF Val66Met and 5-HTTLPR, but the 5-HTTLPR variants trended toward association. Depressive symptoms appeared to act as a mediator on the relationship within the 5-HTTLPR s/s genotype and the severity of tinnitus. CONCLUSION: Our findings provide a speculative idea on the association between the serotonergic system and tinnitus and suggest that depressive symptoms act as a mediator in tinnitus. Therefore, screening for depressive symptoms in patients with tinnitus is essential and intervention for depressive symptoms may help alleviate the severity of tinnitus.

Predictors of Habitual and Addictive Smartphone Behavior in Problematic Smartphone Use.

OBJECTIVE: Smartphones have become common, and problematic smartphone use (PSU) is increasing. Predictors of PSU should be identified to prevent it. Little is known about the role of content types of smartphone use as predictors of PSU. Therefore, we aimed to evaluate the predictors of two proposed concepts of PSU, namely habitual smartphone behavior (SB) and addictive SB, within the context of the application (app) categories. METHODS: We studied 1,039 smartphone users using online surveys conducted between January 2 and 31, 2019. We employed multiple regression analysis to identify the predictors of habitual and addictive SB. We controlled for sex and age (mean=39.20). RESULTS: Common predictors of habitual and addictive SB were the use of social networking services, games, entertainment apps, and average weekend smartphone usage time. The predictors of habitual SB were the use of web and lifestyle apps, weekly usage frequency, and sex (female) and the predictors of addictive SB were the use of shopping apps and sleep duration. CONCLUSION: This study revealed the need to consider habitual and addictive SB in evaluating PSU. The predictors in terms of the content types of smartphone usage can be used to develop monitoring and prevention services for PSU.

Development of the Smartphone Addiction Risk Rating Score for a Smartphone Addiction Management Application.

Smartphone usage characteristics are useful for identification of the risk factors for smartphone addiction. Risk rating scores can be developed based on smartphone usage characteristics. This study aimed to investigate the smartphone addiction risk rating (SARR) score using smartphone usage characteristics. We evaluated 593 smartphone users using online surveys conducted between January 2 and January 31, 2019. We identified 102 smartphone users who were addicted to smartphones and 491 normal users based on the Korean Smartphone Addiction Proneness Scale for Adults. A multivariate logistic regression analysis was used to identify significant risk factors for smartphone addiction. The SARR score was calculated using a nomogram based on the significant risk factors. Weekend average usage time, habitual smartphone behavior, addictive smartphone behavior, social usage, and process usage were the significant risk factors associated with smartphone addiction. Furthermore, we developed the SARR score based on these factors. The SARR score ranged between 0 and 221 points, with the cut-off being 116.5 points. We developed a smartphone addiction management application using the SARR score. The SARR score provided insights for the development of monitoring, prevention, and prompt intervention services for smartphone addiction.

Prevalence and analysis of tobacco use disorder in patients diagnosed with lung cancer.

INTRODUCTION: Tobacco use disorder (TUD), previously known as nicotine dependence, was associated with increased risk of lung cancer. However, little is known about the prevalence of TUD and symptom manifestation in smokers with lung cancer. OBJECTIVES: The aim of the present study was to investigate the prevalence of TUD using DSM-5 diagnostic criteria in patients diagnosed with lung cancer and analyze their tobacco use characteristics. METHODS: A total of 200 histologically confirmed lung cancer patients who used tobacco within the prior 12-month period at the time of diagnosis were recruited for this study. Participants were assessed using interviewer-administered questionnaires to determine TUD symptoms and smoking-related behaviors, and self-administered Fagerstrom Test for Nicotine Dependence (FTND) was also administered. RESULTS: The prevalence of DSM-5 TUD was 92.0% (n = 184). Of a total of 200 subjects, 23 (11.5%), 35 (17.5%), and 126 (63.0%) were classified into mild, moderate, and severe TUD categories, respectively. A total of 19 (81.3%) moderate TUD and 98 (77.8%) severe TUD patients had attempted smoking cessation. Of these subjects, 21 (21.4%) severe TUD and 12 (63.2%) moderate TUD patients tried more than three times. The number of satisfied criteria under DSM-5 TUD was positively correlated with FTND score, cumulative lifetime smoking amount, and daily smoking levels. CONCLUSIONS: Smokers diagnosed with lung cancer showed a high prevalence of DSM-5 TUD. Their heavy and consistent tobacco use suggests reduced motivation to abstain from smoking.

Impact of Age at Childbirth on Maternal Mental Health among Premenopausal Women: The 2010-2012 Korean National Health and Nutrition Examination Survey.

OBJECTIVE: No reports have investigated the influence of age at first or last childbirth on maternal mental health. The aim of this study was to determine whether there is an association between age at first or last childbirth and the mental health of premenopausal women. METHODS: The data used in this study were collected from the 2010 to 2012 Korea National Health and Nutrition Examination Surveys. A total of 3,370 premenopausal women were considered. The association between childbirth age and maternal mental health factors, including stress, depressed mood, and suicidal ideations were analyzed using multiple logistic regression analyses adjusted for confounding factors. RESULTS: After adjusting confounding factors, younger maternal age at first childbirth was found to be associated with an increase in the prevalence of maternal depressed mood and suicidal ideations. Also, older maternal age at last childbirth was related to an increase in maternal stress, depressed mood and suicidal ideations. CONCLUSION: Both younger first childbirth and older last childbirth maternal age may be risk factors for poor outcomes of premenopausal women's mental health. These data support the need for comprehensive mental health assessment for premenopausal women who either gave birth at an age too young or too old.

Altered Plasma Levels of Glial Cell Line-Derived Neurotrophic Factor in Patients with Internet Gaming Disorder: A Case-Control, Pilot Study.

Glial cell line-derived neurotrophic factor (GDNF) has been reported to be involved in negatively regulating the effects of addictive disorders. The objective of this study was to investigate alterations in the levels of GDNF in patients with Internet gaming disorder (IGD) and to assess the relationship between GDNF levels and the severity of IGD indices. Nineteen male patients with IGD and 19 sexmatched control subjects were evaluated for alteration of plasma GDNF levels and for relationship between GDNF levels and clinical characteristics of Internet gaming, including the Young's Internet Addiction Test (Y-IAT). The GDNF levels were found to be significantly low in patients with IGD (103.2±62.0 pg/mL) compared with the levels of controls (245.2±101.6 pg/mL, p<0.001). GDNF levels were negatively correlated with Y-IAT scores (Spearman's rho=-0.645, p=<0.001) and this negative correlation remained even after controlling for multiple variables (r=-0.370, p=0.048). These findings support the assumed role of GDNF in the regulation of IGD.

Gender-Specific Association between Alcohol Consumption and Stress Perception, Depressed Mood, and Suicidal Ideation: The 2010-2015 KNHANES.

OBJECTIVE: Alcohol drinking can cause various psychiatric and medical diseases. Although women generally consume less alcohol than men, they may be at a greater risk for alcohol-related psychological distress. The aim of the current study is to evaluate whether the association between alcohol consumption and psychological distress, including stress, depressed mood, and suicidal ideation and the risks of psychological distress differ based on gender. METHODS: The cross-sectional study included 31,657 participants (17,915 women and 13,742 men) from the 2010-2013 and 2015 Korea National Health and Nutrition Examination Survey. Alcohol drinking and Alcohol Use Disorders Identification Test (AUDIT) levels were assessed for evaluating the amount of alcohol intake and alcohol-related problems. Self-perception of stress, depressed mood, and suicidal ideation were assessed for evaluating psychological distress. Odds ratio and 95% confidence intervals for psychological distress were calculated using multiple logistic regression models. RESULTS: The risks of psychological distress were not significantly associated with drinking level in both sexes. However, the risks of psychological distress were associated with an increase in AUDIT levels, and there were gender differences in the psychological consequences of alcohol-related problems. The association was more drastic in women, and women showed a significant association even though the severity of drinking problem was low with the exception of stress perception. CONCLUSION: The risks of psychological distress were associated with the severity of alcohol-related problems and women were more likely to be susceptible. Therefore, it is recommended that women even at low-risk for problematic drinking should be screened for psychological distress.

Types of problematic smartphone use based on psychiatric symptoms.

To provide appropriate solutions for problematic smartphone use, we need to first understand its types. This study aimed to identify types of problematic smartphone use based on psychiatric symptoms, using the decision tree method. We recruited 5,372 smartphone users from online surveys conducted between February 3 and February 22, 2016. Based on scores on the Korean Smartphone Addiction Proneness Scale for Adults (S-Scale), 974 smartphone users were assigned to the smartphone-dependent group and 4398 users were assigned to the normal group. The data-mining technique of C5.0 decision tree was applied. We used 15 input variables, including demographic and psychological factors. Four psychiatric variables emerged as the most important predictors: self-control (Sc; 66%), anxiety (Anx; 25%), depression (Dep; 7%), and dysfunctional impulsivities (Imp; 3%). We identified the following five types of problematic smartphone use: (1) non-comorbid, (2) self-control, (3) Sc + Anx, (4) Sc + Anx + Dep, and (5) Sc + Anx + Dep + Imp. We found that 74% of smartphone-dependent users had psychiatric symptoms. The ratio of participants belonging to the non-comorbid and self-control types was 64%. We proposed that these types of problematic smartphone use may be used for the development of an appropriate service for controlling and preventing such behaviors in adults.

Gender Differences Affecting Psychiatric Distress and Tinnitus Severity.

OBJECTIVE: This study evaluated gender differences in the relationship between psychiatric distress and subjective tinnitus severity. METHODS: This cross-sectional study included 134 female and 114 male patients who visited the otology outpatient clinic at Seoul St. Mary's Hospital for tinnitus from February to July 2015. Patients completed a series of instruments, including the Tinnitus Handicap Inventory, Beck Depression Inventory, Korean version of Brief Encounter Psychosocial Instrument (BEPSI-K), and visual analogue scales assessing various tinnitus characteristics (loudness, awareness, annoyance, and effect on life). RESULTS: Tinnitus severity did not significantly differ between the gender groups (p=0.632), and it correlated significantly with tinnitus characteristics and psychiatric distress. Partial correlations between tinnitus severity and depressive symptoms were stronger in males (r=0.411, p＜0.01) than in females (r=0.304, p＜0.01) while controlling for duration of tinnitus and tinnitus characteristics. However, stress (BEPSI-K) was positively correlated with tinnitus severity in only males (r=0.463, p＜0.01). A multiple regression analysis revealed that effect of tinnitus on life, depressive symptoms, and stress were significantly associated with tinnitus severity in males, whereas only tinnitus annoyance and depressive symptoms were associated with tinnitus severity in females. CONCLUSION: Tinnitus severity was significantly correlated with depressive symptoms and stress, and there were gender differences in the relationship between tinnitus severity and psychiatric components. It is necessary to be vigilant of psychiatric symptoms among patients with tinnitus who visit the otology outpatient clinic, especially for male patients.

Gaming Device Usage Patterns Predict Internet Gaming Disorder: Comparison across Different Gaming Device Usage Patterns.

Gaming behaviors have been significantly influenced by smartphones. This study was designed to explore gaming behaviors and clinical characteristics across different gaming device usage patterns and the role of the patterns on Internet gaming disorder (IGD). Responders of an online survey regarding smartphone and online game usage were classified by different gaming device usage patterns: (1) individuals who played only computer games; (2) individuals who played computer games more than smartphone games; (3) individuals who played computer and smartphone games evenly; (4) individuals who played smartphone games more than computer games; (5) individuals who played only smartphone games. Data on demographics, gaming-related behaviors, and scales for Internet and smartphone addiction, depression, anxiety disorder, and substance use were collected. Combined users, especially those who played computer and smartphone games evenly, had higher prevalence of IGD, depression, anxiety disorder, and substance use disorder. These subjects were more prone to develop IGD than reference group (computer only gamers) (B = 0.457, odds ratio = 1.579). Smartphone only gamers had the lowest prevalence of IGD, spent the least time and money on gaming, and showed lowest scores of Internet and smartphone addiction. Our findings suggest that gaming device usage patterns may be associated with the occurrence, course, and prognosis of IGD.

The association between the nicotinic acetylcholine receptor α4 subunit gene (CHRNA4) rs1044396 and Internet gaming disorder in Korean male adults.

The primary aim of this study was to investigate the genetic predisposition of Internet gaming disorder (IGD), and the secondary aim was to compare the results to those of alcohol dependence (AD). Two independent case-control studies were conducted. A total of 30 male participants with IGD, diagnosed according to the 5th edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) criteria, and 30 sex-matched controls participated in study 1. We designed targeted exome sequencing (TES) to test for 72 candidate genes that have been implicated in the pathogenesis of addiction. The genes included seven neurotransmitter (dopamine, serotonin, glutamate, r-aminobutyric acid (GABA), norepinephrine, acetylcholine, and opioid) system genes. A total of 31 male in-patients with AD and 29 normal male controls (NC) were enrolled in study 2. The same 72 genes included in study 1 and ten additional genes related to alcohol-metabolic enzyme were selected as the target genes, and we identified the genetic variants using the same method (TES). The IGD group had a lower frequency of the T allele of rs1044396 in the nicotinic acetylcholine receptor alpha 4 subunit (CHRNA4), and this variant represents a protective allele against IGD. However, we did not find a significant difference in the polymorphisms of the 72 genes that encode neurotransmitter systems between the AD and NC groups. This study demonstrated that rs1044396 of CHRNA4 was significantly associated with IGD.

An association study of Taq1A ANKK1 and C957T and - 141C DRD2 polymorphisms in adults with internet gaming disorder: a pilot study.

BACKGROUND: Though Internet gaming disorder (IGD) is considered to share similar genetic vulnerability with substance addictions, little has been explored about the role of the genetic variants on IGD. This pilot study was designed to investigate the association of the Taq1A polymorphism of the ankyrin repeat and kinase domain containing 1 (ANKK1) gene and C957T and - 141C of the dopamine D2 receptor (DRD2) with IGD and their role on the personality and temperament traits in IGD among adult population. METHODS: Sixty-three subjects with IGD and 87 control subjects who regularly played Internet games were recruited. Self-administered questionnaires on self-control, dysfunctional impulsivity, and temperament and character domains were done. The Taq1A ANKK1 and the C957T and - 141C ins/del from the DRD2 genes were genotyped using the specific TaqMan PCR assay. RESULTS: The distributions of allele and genotype frequencies were not significantly different between the IGD and control groups in both genders. In male, excessive gaming and use of gaming to escape from a negative feeling were associated with the del- genotype of the - 141C. Among IGD, the del+ genotype was associated with higher novelty seeking. Logistic regression showed no predictive value of these polymorphisms for IGD when using age and gender as covariates. CONCLUSIONS: Though no direct association of the Taq1A ANKK1 and C957T DRD2 variants with IGD were observed, the - 141C polymorphism may play a role in IGD via mediating symptoms or temperament traits.

Association between mental health status and bone mineral density: Analysis of the 2008-2010 Korea national health and nutrition examination survey.

The current study aimed to investigate the association between mental health status and bone mineral density (BMD) using data from the Korean National Health and Nutrition Examination Survey (KNHANES) 2008-2010. We enrolled 15,876 South Korean participants (4,010 postmenopausal females, 4,836 premenopausal females, and 7,016 males, all aged 20 years or older). BMD was measured using dual-energy radiography absorptiometry at the femoral neck (NK), lumbar spine (LSP), and total femur (TFM). Mental health status data were obtained from a self-report questionnaire that assessed psychological stress, depressed mood, and suicidal ideation. Psychological stress was negatively correlated with BMD in the LSP, NK, and TFM for the male group. Depressed mood was associated with lower BMD in the LSP, NK and TFM for the premenopausal female group, and in the LSP for the male group. Suicidal ideation was associated with lower BMD in the NK and TFM for the male group. Mental health problems were associated with lower BMD, especially in premenopausal females and males. Future investigations should focus on the shared pathophysiology between mental health problems and BMD, and the interrelationship between increased BMD and recovery from mental health problems.

Chronic saponin treatment attenuates damage to the pancreas in chronic alcohol-treated diabetic rats.

BACKGROUND: Chronic heavy alcohol consumption may raise the risk of developing type 2 diabetes mellitus. Saponins inhibit apoptosis of pancreatic islet cells and reduce lipid parameters. The present study was designed to investigate the effect of saponin on chronic ethanol-treated diabetic rats. METHODS: Long-Evans Tokushima Fatty (LETO) and Otsuka Long-Evans Tokushima Fatty (OLETF) rats were pair-fed a Lieber-DeCarli diet with and without 5% ethanol for 12 wks. Two weeks after starting the pair-feeding with the Lieber-DeCarli diet, intraperitoneal injection of saponin was performed for 10 wks. To perform the experiments, rats were divided as follows: LETO-Control (LC), LETO-Ethanol (LE), LETO-Ethanol-Saponin (LES), OLETF-Control (OC), OLETF-Ethanol (OE), and OLETF-Ethanol-Saponin (OES). RESULTS: The weights of epididymal and mesenteric fat tissue in LES and OES rats were the lightest from among the LETO and OLETF groups, respectively. The secretion of alanine aminotransferase and cholesterol in OES rats decreased significantly compared to their secretion in OC and OE rats, respectively. The islets of the pancreas in LE and OE rats showed clean, unclear, and smaller morphology compared to those of LC, LES, OC, and OES rats. In addition, the expression of insulin in the islets of the pancreas in LC, LES, OC, and OES rats was higher than in LE and OE rats. CONCLUSION: Saponin may not only be helpful in alleviating the rapid progress of diabetes due to chronic alcohol consumption in diabetic patients, but may also show potential as an antidiabetic drug candidate for diabetic patients who chronically consume alcohol.

Reliability and Validity of the Korean Version of the General-Food Craving Questionnaire-Trait for Children.

OBJECTIVE: The General-Food Craving Questionnaire-Trait (G-FCQ-T) is a validated, assessment scale for food craving. The aim of this study was to measure its reliability and validity for Korean children. METHODS: A total of 172 children (94 boys and 78 girls) were selected to fill out a set of questionnaires, including the G-FCQ-T, the Children's version of the Dutch Eating Behavior Questionnaire (DEBQ-C), and the Three-Factor Eating Questionnaire (TFEQ) in the Korean language. RESULTS: The internal consistency (Cronbach's alpha=0.933) and test-retest reliability (r=0.653) were satisfactory. The G-FCQ-T showed a significantly positive correlation with the DEBQ-C (r=0.560) and the TFEQ (r=0.397). The optimum cutoff score of the G-FCQ-T set by Receiver Operating Characteristics analysis was 51, with sensitivity and specificity of 0.833 and 0.825, respectively, for children. CONCLUSION: The G-FCQ-T showed good reliability and validity for assessing food craving for children and could become a practial instrument in clinical and research settings.

Targeted exome sequencing for the identification of a protective variant against Internet gaming disorder at rs2229910 of neurotrophic tyrosine kinase receptor, type 3 (NTRK3): A pilot study.

Background and aims Internet gaming disorder (IGD) has gained recognition as a potential new diagnosis in the fifth revision of the Diagnostic and Statistical Manual of Mental Disorders, but genetic evidence supporting this disorder remains scarce. Methods In this study, targeted exome sequencing was conducted in 30 IGD patients and 30 control subjects with a focus on genes linked to various neurotransmitters associated with substance and non-substance addictions, depression, and attention deficit hyperactivity disorder. Results rs2229910 of neurotrophic tyrosine kinase receptor, type 3 (NTRK3) was the only single nucleotide polymorphism (SNP) that exhibited a significantly different minor allele frequency in IGD subjects compared to controls (p = .01932), suggesting that this SNP has a protective effect against IGD (odds ratio = 0.1541). The presence of this potentially protective allele was also associated with less time spent on Internet gaming and lower scores on the Young's Internet Addiction Test and Korean Internet Addiction Proneness Scale for Adults. Conclusions The results of this first targeted exome sequencing study of IGD subjects indicate that rs2229910 of NTRK3 is a genetic variant that is significantly related to IGD. These findings may have significant implications for future research investigating the genetics of IGD and other behavioral addictions.

Predictors and patterns of problematic Internet game use using a decision tree model.

Background and aims Problematic Internet game use is an important social issue that increases social expenditures for both individuals and nations. This study identified predictors and patterns of problematic Internet game use. Methods Data were collected from online surveys between November 26 and December 26, 2014. We identified 3,881 Internet game users from a total of 5,003 respondents. A total of 511 participants were assigned to the problematic Internet game user group according to the Diagnostic and Statistical Manual of Mental Disorders Internet gaming disorder criteria. From the remaining 3,370 participants, we used propensity score matching to develop a normal comparison group of 511 participants. In all, 1,022 participants were analyzed using the chi-square automatic interaction detector (CHAID) algorithm. Results According to the CHAID algorithm, six important predictors were found: gaming costs (50%), average weekday gaming time (23%), offline Internet gaming community meeting attendance (13%), average weekend and holiday gaming time (7%), marital status (4%), and self-perceptions of addiction to Internet game use (3%). In addition, three patterns out of six classification rules were explored: cost-consuming, socializing, and solitary gamers. Conclusion This study provides direction for future work on the screening of problematic Internet game use in adults.