Recently, the American Psychiatric Association included Internet gaming disorder (IGD) in the appendix of the 5th edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5). The main aim of the current study was to test the reliability and validity of 4 survey instruments to measure IGD on the basis of the 9 criteria from the DSM-5: a long (27-item) and short (9-item) polytomous scale and a long (27-item) and short (9-item) dichotomous scale. The psychometric properties of these scales were tested among a representative sample of 2,444 Dutch adolescents and adults, ages 13-40 years. Confirmatory factor analyses demonstrated that the structural validity (i.e., the dimensional structure) of all scales was satisfactory. Both types of assessment (polytomous and dichotomous) were also reliable (i.e., internally consistent) and showed good criterion-related validity, as indicated by positive correlations with time spent playing games, loneliness, and aggression and negative correlations with self-esteem, prosocial behavior, and life satisfaction. The dichotomous 9-item IGD scale showed solid psychometric properties and was the most practical scale for diagnostic purposes. Latent class analysis of this dichotomous scale indicated that 3 groups could be discerned: normal gamers, risky gamers, and disordered gamers. On the basis of the number of people in this last group, the prevalence of IGD among 13- through 40-year-olds in the Netherlands is approximately 4%. If the DSM-5 threshold for diagnosis (experiencing 5 or more criteria) is applied, the prevalence of disordered gamers is more than 5%.
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