An article published today in NewScientist Magazine says that frequent game playing creates what is usually called "drug memory" in which the context of gaming triggers intense craving to play.
In tests, people for whom gaming has replaced other activities, such as socializing, were stimulated into intense craving to play by simply being shown screenshots of their favorite games. Gaming "addicts" also startled much more easily than a control group.
The research was headed by Sabine Grusser of Germany's Charit University Medicine Berlin. Grusser says he research implies that gaming should be classified as an addictive activity, like gambling.