Not much. From the U.S. Department of Justice's National Criminal Justice Reference Service (publication NCJ 145534): "Of all psychoactive substances, alcohol is the only one whose consumption has been shown to commonly increase aggression. [...] Marijuana and opiates temporarily inhibit violent behavior [...] There is no evidence to support the claim that snorting or injecting cocaine stimulates violent behavior. [...] Anecdotal reports notwithstanding, no research evidence supports the notion that becoming high on hallucinogens, amphetamines, or PCP stimulates violent behavior in any systematic manner."
Keep up (what you think is) the good work.