Alcoholism? Substance abuse? These are national scale issues, not gaming group scale. It isn't like there's a "war on drugs" because of a few stoner gamers, and I would not expect that the rate of abuse among gamers is really notably higher than in the general population.
I think maybe in gaming you have a sort of reporting bias - in most other hobbies, you go out into public to partake of the social aspects of the hobby, and in public, abusers and troubled folks are typically trying to cover their problems. In gaming, you frequently go into someone's home - the social dynamics are different, so you may get to know more about the problems the people have.
By which I mean - you probably know more about your gamer friends than about others. How do you know you aren't really surrounded by people with troubles who aren't gamers?
I think maybe in gaming you have a sort of reporting bias - in most other hobbies, you go out into public to partake of the social aspects of the hobby, and in public, abusers and troubled folks are typically trying to cover their problems. In gaming, you frequently go into someone's home - the social dynamics are different, so you may get to know more about the problems the people have.
By which I mean - you probably know more about your gamer friends than about others. How do you know you aren't really surrounded by people with troubles who aren't gamers?