Defining tolerance in Internet Gaming disorder: Isn't it time?

The inclusion of internet gaming disorder (IGD) in the appendix of the DSM-5 is a preliminary endorsement of gaming as an addictive behaviour [1]. Further research is now required to validate the proposed criteria [2]. However, applying the concept of tolerance to a complex activity such as gaming may be more difficult than is currently acknowledged in the DSM-5 formulation. There has been some preliminary scholarly debate that has examined the topic of gaming tolerance [3], relative to wider discussion of other IGD features such as preoccupation [4–6], withdrawal [7,8] and harm [9,10]. However, an important question that remains unresolved is: what specific gaming stimuli do individuals with IGD develop a tolerance for? The DSM-5 conceptualization refers to ‘the
need to spend an increasing amount of time engaged in Internet games’ ([1], p. 795). Although, at first glance, this may be an appealing definition due to its simplicity and objectivity, it may not necessarily be valid to equate time with dosage, in that this variable alone may fail to capture many other factors that motivate and maintain excessive behaviour [11].