on pathological on-line gaming has increased substantially over the past two decades. 1,2 Internet gaming disorder (IGD) was included in the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) as a tentative disorder needing further research. 3 The DSM-5 defines IGD as "persistent and recurrent use of the internet to engage in games, often with other players, leading to clinically significant impairment or distress. " The nine criteria for IGD in the DSM-5 are based on preliminary studies outlining the criteria for substance use disorder and gambling disorder. IGD, as a form of behavioral addiction, shares typical characteristics with substance addiction, including withdrawal, tolerance, loss of control, and cravings. 4 Before the DSM-5 criteria, var-