And, violent movies reduce violent crime.
I think that limiting the scope to violent movies is... well... limiting.
I made a chart of video game sales against violent crime for available data, '95-'05.
Hypothesis: Most high sales-volume games are violent to some extent.
This violence allows the release of aggression in a virtual setting, thus to some extent reducing real-life violent crime.
As discussed in the above article, the main reduction in violent crime has been seen in the 12-19 year old set which is the prime demographic for violent video games.
Just raising point for discussion because I think they're interesting. This is not a peer-reviewed study by any means.