Abstract
AIM: The Internet Gaming Disorder Scale is a 9-item screening instrument developed based on the diagnostic criteria for Internet Gaming Disorder (IGD) in the DSM-5. This study aimed to examine the reliability and validity of the Internet Gaming Disorder Scale for children (IGDS-C) in Japanese clinical and nonclinical populations. METHODS: The study included clinical outpatients aged 9-29 with problematic game use and nonclinical adolescents aged 12-18 who played online games at least once a week. Reliability was examined by calculating internal consistency and test-retest reliability. Validity was assessed using Spearman's correlation and Confirmatory Factor Analysis (CFA). RESULTS: A total of 746 participants (93 clinical, 653 nonclinical) were eligible for statistical analysis. Reliability results revealed acceptable internal consistency (Cronbach's α = 0.87) and test-retest reliability (intraclass correlation coefficient = 0.62). CFA results (Comparative Fit Index = 0.92, Tucker-Lewis Index = 0.90, root mean square error of approximation = 0.10, standardized root mean square residual = 0.05, factor loadings = 0.59-0.71) and significant correlations with the GAMES test, psychological distress, and gaming hours verified the validity of the IGDS-C. CONCLUSION: The study verified the reliability and validity of the IGDS-C in Japanese clinical and nonclinical participants, suggesting that it generally reflects the severity of IGD well.