Recently, the correlation between on-line game playing and aggressiveness has been an important
and controversial issue, especially in children and adolescents. The current article summarized
the hypothesis of on-line game playing and aggressiveness in terms of neutral view, including
General Aggression Model, meta-analysis, and the limitations of both theories. In addition,
we reviewed brain studies of on-line game playing and the limitation of these studies, such as
cross-sectional approach, small number of subjects, and variable etiologies of aggressiveness.
We suggest that cohort study, large number of subjects, genre of game, environmental factors,
and various etiologies of aggressiveness should be considered in studies of on-line game playing
and increased aggressiveness.