No matter how you dice it, video games motivate LOTS of students. Journal of Personality and Social Psychology, While this information could be applied to further study, the survey would need to be expanded and refined and the survey would need a much larger sample in order to have significant results.
The "sweet spot" for video game playing is one hour or less a day. On the contrary, video game playing in this study was actually linked with higher academic achievement -- even after the researchers controlled for socio-economic status and other relevant factors Kovess-Masfety et al Other studies hint that it's the kind of game play that matters.
The students were all Caucasian and middle class.
Pathological gamers are likely to develop anxiety, insomnia, social isolation, and depression. But when one combines all relevant empirical studies using meta-analytic techniques, five separate effects emerge with considerable consistency.
The study focused largely on TV and movies as the basis for the first three, but specifically mentioned the effect of videogame violence as increasing the risks of violence in teens.
Students were asked to complete a five question survey that asked them to rate their video game usage and academic performance using a Likert Scale format.
If you have introduced your teen to gaming, it is your responsibility to know the kind of games they are playing and their duration.