artistic expression and violence

[gib65]

Have there ever been any studies done to show that one's freedom to express him/herself artistically is negatively correlated with the amount of violence he/she is prone to engage in? I started wondering this when I was thinking about these gothic/heavy-metal rock bands like Marilyn Manson, Rob Zombie, Limp Biscuit, etc. and how I've never heard of them going to jail for serious crimes of any sort. Do you think that artistic expression serves as an alternate channel through which to "exercise our demons"? If so, do you think this is why countries with the most violence are usually also the ones with the most censorship on the press and individual expression?