Background and Aims: A definition of gaming disorder (GD) was introduced in ICD-11. The purpose of this study was to develop a short screening test for GD, utilizing a reference GD group. It also sought to estimate the prevalence of GD among individuals, representative of the general young population in Japan.Methods: Two hundred eighty one men and women selected from the general population, aged between 10 and 29 years, and 44 treatment seekers at our center completed a self-reported questionnaire comprising candidate questions for the screening test. The reference group with ICD-11 GD was established, based on face-to-face interviews with behavioral addiction experts, using a diagnostic interview instrument. The questions in the screening test were selected to best differentiate those who had GD from those who did not, and the cutoff value was determined using the Youden index.Results: A nine-item screening test (GAMES test) was developed. The sensitivity and specificity of the test were both 98% and the positive predictive value in the study sample was 91%. The GAMES test comprised two factors, showed high internal consistency and was highly reproducible. The estimated prevalence of GD among the general young population was 7.6% (95% confidence interval; 6.6–8.7%) for males and 2.5% (1.9–3.2%) for females, with a combined prevalence of 5.1% (4.5–5.8%).Discussion and Conclusion: The GAMES test shows high validity and reliability for screening of ICD-11 GD. The estimated prevalence of 5.1% among the general young population was comparable to the pooled estimates of young people globally.

Background and aims: The World Health Organization included gaming disorder (GD) in the eleventh revision of International Classification of Diseases in 2019. Due to the lack of diagnostic tools for GD, a definition has not been adequately applied. Therefore, this study aimed to apply an operationalized definition of GD to treatment-seekers. The relationship between the diagnoses of GD and Internet gaming disorder (IGD) in the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders was also examined. Methods: Study participants comprised 241 treatment-seekers who had engaged in excessive gaming and experienced related problems. Psychiatrists applied the GD diagnostic criteria to the participants using a diagnostic form developed for this study. Information on gaming behavior and functional impairment was obtained through face-to-face interviews conducted by clinical psychologists. Results: In total, 78.4 and 83.0% of the participants fulfilled the GD and IGD diagnostic criteria, respectively. The sensitivity and specificity of GD diagnosis were both high when the IGD diagnosis was used as the gold standard. Participants with GD preferred online PC and console games, spent significantly more time gaming, and showed a higher level of functional impairment compared to those who did not fulfill the GD diagnostic criteria. Discussion and Conclusion: The definition of GD can be successfully applied to treatment-seekers with excessive gaming and related problems. A high concordance of GD and IGD diagnoses was found in those participants with relatively severe symptoms. The development and validation of a diagnostic tool for GD should be explored in future studies.

Most schools in Japan were closed in spring 2020 due to the novel coronavirus disease 2019 (COVID-19) pandemic. We investigated lifestyle and internet use among junior high school students across eight schools after long-term school closure and compared the data with those we obtained from previous surveys. In the summers of 2018, 2019, and 2020, we conducted questionnaire surveys on seventh-grade students from the same schools. In total, 2270 participants were analyzed. All questionnaires included items regarding background, bedtime, and internet use. The participants of the 2020 survey had significantly less sleepiness during classes and longer internet use times compared with those of the previous surveys. In the 2020 survey, the rate of problematic internet use (Young’s Diagnostic Questionnaire score, ≥5) was not significantly different from the results of previous surveys. The COVID-19 pandemic might have strongly influenced the sleepiness experienced by students in classes and increased the time spent using the internet since the summer of 2020. Our results indicate the need for attempts to encourage students to improve their sleep habits and moderate their media use.

Background and aims: Although the Ten-Item Internet Gaming Disorder Test (IGDT-10) has been translated into Japanese and widely used, the Japanese version has not previously been validated. We used the clinical diagnosis of IGD as a gold standard for validating the test.Methods: The Japanese version was validated using 244 gamers drawn from the general young population in Japan. Expert interviews using the Japanese version of the Structured Clinical Interview for Internet Gaming Disorder evaluated diagnoses of Internet gaming disorder (IGD). This resulted in a diagnosis of IGD for eight individuals, categorized as the gold standard group. The screening performance of the two Japanese versions with different scoring conditions was examined: the scoring method proposed by the original study (original version) and a less stringent scoring method where responses of either “often” or “sometimes” were regarded as affirmative (modified version).Results: The results of the sensitivity and specificity analyses, the Cronbach's alpha and the receiver operating characteristics analysis revealed a higher screening performance for the modified versus the original version. The optimum cutoff for the modified version was 5 or more – the sensitivity, specificity, and Youden's index were 87.5, 85.2, and 72.7%, respectively. The rate of probable IGD using the original and modified versions were 1.8% and 11.3%, respectively.Discussion and conclusion: A less stringent scoring method for the Japanese version of IGDT-10 showed a higher screening performance than the original scoring method. Future studies comprising different ethnic groups and gaming cultures should further examine the suggested scoring method.

Background and aims. Japan has a unique gambling environment compared with other countries: pachinko and pachislot dominate the gambling market and are easily accessible. We investigated the clinical characteristics of treatment-seeking Japanese patients with gambling disorder (GD), focusing on factors related to GD severity. Methods. This cross-sectional analysis used data from the Japan Collaborative Clinical Study on Gambling Disorder (JaCCS-G), a multicenter collaborative prospective study evaluating the effectiveness of outpatient treatment for GD. Twenty medical institutions with outpatient gambling clinics participated in this study. Individuals with GD who visited participating facilities and were diagnosed with GD based on the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, were included. Semi-structured interviews were conducted to assess gambling behavior and psychiatric comorbidities. We administered the Gambling Symptom Assessment Scale to assess gambling symptom severity, the Gambling Related Cognitions Scale to assess irrational thoughts in GD, and the Barratt Impulsiveness Scale (11th version) (BIS-11) to assess impulsivity. Results. A total of 202 patients with GD participated in the JACCS-G. Pachinko was the most common type of gambling seen in patients with GD, followed by pachislot and horse racing. BIS-11 total score significantly differed among patients with mild, moderate, and severe GD. Antisocial personality disorder (ASPD) was associated with GD severity. Discussion and conclusions. These results reflect the unique gambling environment in Japan, where pachinko is the most accessible and prevalent form of gambling. Assessing GD severity may help identify individuals with heightened impulsivity or ASPD, enabling more targeted interventions and improved treatment strategies. (249 words).

Background and Aims: Gambling-related cognitive distortions (GRCD) sustain gambling behaviors despite adverse consequences. While previous studies have shown an association between GRCD and gambling disorder (GD) severity, few have conducted causal analyses. We aimed to examine temporal changes in GRCD among treatment-seeking patients and to investigate whether GRCD predicts subsequent gambling severity. Methods: This one-year follow-up study was conducted in collaboration with 20 addiction-specialized medical institutions. The participants were 100 male patients diagnosed with GD (mean age: 37.2±8.5). We also examined the differences in GRCD improvement based on gambling relapse after treatment initiation. GRCD were assessed using the Gambling-Related Cognitions Scale (GRCS), and gambling severity was measured using the Problem Gambling Severity Index (PGSI). Gambling engaement was assessed using a self-report questionnaire. Temporal changes were analyzed using repeated-measures ANOVA, and the causal relationship between the GRCD and the PGSI was examined using a cross-lagged panel model (CLPM). Results: Overall, GRCD significantly decreased within 6 months of treatment initiation and then stabilized. The abstinence group had significantly lower GRCD scores than the non-abstinence group at all the timepoints. CLPM identified Perceived Inability to Stop Gambling (IS) as the only GRCD subscale that significantly predicted PGSI scores at 12 months. Discussion: This study demonstrates that GRCD predict the severity of subsequent gambling disorders. In particular, IS has been identified as a critical target for interventions. Conclusions: These findings provide valuable evidence of a causal relationship between GRCD and gambling severity and underscore the importance of targeting IS in treatment.