I have read some studies on video game addictions (chemically) and (I believe) video game addictions are obviously not real by definition because there is no chemical dependency on the activity. However, as most video gamers would agree, having a healthy caffiene addiction is a normal, almost necessary characteristic of a good gamer. (good as in, addicted good?)

Caffeine is used the same way as many drugs (unknowingly) as relief response to stress. Any addictive drug taken when mentally relieving stress or performing any specific activity, creates addicted habits.

Consider how when people who 'used' to smoke go outside with the smokers (in states wherein smoking inside is illegal) How people cant deal with stress without their nicotine, they must go outside. Consider then if you took a mild addictive substance while only playing the piano- you would gain immediate stress relief because the dopamine in your brain is being released (moreso) because your body and mind are used to having it released unnaturally whenever you play piano.

As for the negative actions associated with addicted video gamers, you can find this will increase the same as any unfortunate decisions is made simply because the-more-people-there-are the-more-stupid-people-there-are. Immature people will do stupid things, and regardless of their background, addiction as a catalyst has made people do crazy things throughout history so, either pay attention to what you put into your body or start regulating stupidity.