It's complex. I've known two people who have seriously messed up their lives as a result of excessive gaming and one who came close (but pulled back at the last minute). I've known a lot more people who fouled up their lives for other reasons.
The two I knew who seriously messed up their lives were friends from my university days who managed to get so heavily into the QuakeWorld/Quake 3 online scene that they failed their exams at the end of their second year and were thrown out (my university didn't "do" second chances). One of them went into the workplace without a degree (and is doing more or less ok now, almost 15 years later, though probably not in the field he wanted to be in) while the other enrolled at another university and came damned close to flunking out a second time (but scraped graduation and is now a teacher, so draw your own conclusions).
The near-miss was more recent. A friend I've known for about a decade got so heavily into an MMO last year that it started to affect his attendance and performance at work. A few of us spotted what was happening and did a bit of an "intervention" (god, I hate that term, but I can't think of a better one). The immediate result was a week long sulk - but after that, he realised the danger he was in and pulled back from the edge.
Thing is, though, I'm not ultimately convinced that "gaming" was a unique factor in either of those cases. In both cases, I think the social obligations that existed around gaming were a bigger factor. The Quake-pair weren't just playing the game; they were heavily involved in the competitive scene and had weekly practice and event schedules imposed on them by their clans. They both knew (one more than the other, perhaps) that they should be playing less, but didn't have the experience or maturity to tell their clan-mates when enough was enough. The MMO-player was, as he later admitted, more or less hating the game, but was so bound into his guild's hierarchy and structure that he felt he couldn't stop playing (or even cut back) for fear of letting other people down. So it wasn't so much video-game addiction as it was a kind of social entrapment.
Thing is, I've also seen people mess up their lives even more spectacularly for non-gaming reasons. In my first "grown up" job, one of my colleagues was into mountaineering. Seriously so. He'd take months of unpaid leave each year to go on expeditions. He'd done a couple of Himalayan 8,000ers as well as a whole load of peaks in Alaska and the Andes. And over time, it destroyed his life. His marriage fell apart, he lost contact with his son and, when redundancies came around at the office, he was the first one out the door; his lengthy absences meant that people had gotten used to doing without him, so he wasn't able to pull the "look indispensable" trick.
Another guy I was at university with ended up not just flunking out of his course but also winding up tens of thousands of GBP in debt. How? Poker. He convinced himself that as an "elite" maths student, he would be able to clean up. Turns out he couldn't. He ended up hopelessly addicted and throwing good money after bad.
I've also seen people wreck their lives through mundane and even unpleasant stuff. One guy I worked with got so drawn into work for the building management committee for the apartment block he lived in that it took over his life to the point he was spending most of the working day on it - and again, he was out the door at the first whiff of redundancies. He always told people that he was only doing it because he felt people were depending on him...
People are remarkably adept at finding ways to wreck their own lives and will use any tool at hand to do so. Games can be one of those tools and there certainly seem to be some people with a high general propensity to addictive behaviour who will be especially prone to gaming addiction. But for those people, I can't escape the view that if it wasn't gaming that brought them down, it would just be something else.
As for gaming and violence, which is the main point of TFA... meh. For me, gaming has always been stress relief and a harmless outlet for violent impulses.
There might be a separate issue around imitative behaviour in certain cases. That friend I mentioned before who ended up a teacher (and who many not, I grant you, be the most objective judge) takes the view that the only games which cause a problem in school are the 2d fighting games (Street Fighter, Mortal Kombat and the like) because of the dumber kids trying to imitate them and hurting themselves or somebody else. But I can imagine that potentially being just as true for, say, martial arts movies. He tells me he has far more problems with "collectible" non-video games (i,e. trading cards and the like), where disputes over theft and ownership are much more likely to escalate into violence.