Although the point prevalence of internet gaming disorder (IGD) diagnosis in the 2003/2004 birth cohorts of Trondheim, Norway, was low, 10% of boys fulfilled the criteria for a diagnosis at least once during preadolescence and adolescence. IGD symptoms at age 10 were only weakly related to IGD symptoms in mid- and late adolescence. However, as Heavy involvement symptoms predicted later increases in Negative consequences symptoms from age 12 onwards, early adolescence may offer a window of opportunity for when interventions might intersect a development toward a full-blown IGD diagnosis before symptoms become more intertwined with additional problems and resistant to change.