In my opinion the video games like first person shooter give you the possibility to blow off steam and if you can't distinguish real and not real, I think that having the possibility to easily buy a gun is a bigger problem because you can't shoot without a gun.
Even if other people say that you can buy it on the black market, you can compare it with europe... well not that much shootings...

Taking hundreds of different pills that can be described legally in America is the real problem, encouraging other mental illnesses. These medicaments make everything worse but the pharma industry got their profit.