An international meta-analysis over 34 jurisdictions quantified the effect size of gender as small, with most effect in Asia, lesser in Europe and Africa, and null in North America, and further finding that economic factors, internet availability, social norms and addiction-related health factors mediate the effect of gender, with nations with a greater GDP per capita having less differences in video game addiction between genders.Comorbid psychiatric disorders act as both risk factors and consequences. Indeed, there is a strong association between video game addiction and anxiety, depression, ADHD, social phobia, and poor psycho-social support. ADHD and its symptoms, such as impulsivity and conduct problems, also increase risks of developing video game disorder. Although internet gaming disorder has a strong relationship with obsessive-compulsive disorder, it is not specific and internet gaming disorder is both phenomenologically and neurobiologically distinct, which indicates that internet gaming disorder is more characterized by impulsivity than compulsivity. Familial factors appear to play an important role, although not well understood.Some personality traits, such as high neuroticism, high impulsivity, and high aggressiveness are consistently significant predictors of internet gaming disorder, and combination of personality traits seem to play a pivotal role in the acquisition, maintenance and development of the disorder. Mechanisms
Although there is much research since the 1980s on problematic online gaming use, the mechanisms are not well understood, due to inconsistent definitions used in studies. Video game structure
Some theories focus on the presumed built-in reward systems of video games, such as compulsion loops, to explain their potentially addictive nature.
Hagedorn & Young have suggested that social dependence may arise due to video games occurring online where players interact with others and the relationships "often become more important for gamers than real-life relationships". Controversy and alternative viewpoints
Common challenges involve the reliability of the methodology and validity of the results in some studies. Many rely on self-surveys from university students and also lack time frames making it difficult to study the impact, if any, of addiction on a long term scale. Other concerns also address the definition of addiction and how to measure it, questioning whether or not time is a proper unit to determine how addicted someone is to gaming. Daria Joanna Kuss and Mark D. Griffiths have argued the current scientific knowledge on internet gaming addiction is copious in scope and complexity. They state that instead, a simple framework should be provided to allow all current and future studies to be categorised, as internet gaming addiction lies on a continuum beginning with etiology and risk factors all the way through the development of "full-blown" addiction and ending with ramifications and potential treatment. In addition, they caution the deployment of the label "addiction" since it heavily denotes the use of substances or engagement in certain behaviors. Finally, the researcher promotes other researchers to assess the validity and reliability of existing measures instead of developing additional measurement instruments.Other challenges include the lack of context of the participants life and the negative portrayal of gaming addicts.