I'm sure there have been studies done, but I don't know them off the top of my head. I'm speaking from personal experience here (since apparently I need to spell this out in my comments): I would say that violent video games _may_ play a role in someone who then proceeds to go down the path of "violence porn." But usually, there are other factors drawing them to that place (i.e., bullying).
Likewise, I've often seen porn used as a tool to deal with other subsurface issues. The high of the hormone rush brings temporary relief, but like most highs, it requires more and more for it to stay the same.
Interestingly, no one in any of the comments so far has provided any anecdotal experiences of porn resulting in the opposite effect on someone. I don't doubt it happens, but it seems more people are focused on attacking my statement rather than engaging in a conversation. I'm happy to hear more stories.