"Despite the often violent lyrical content in some heavy metal songs, recently published research has shown that fans do not become sensitized to violence, which casts doubt on the previously assumed negative effects of long-term exposure to such music," the researcher wrote. "Indeed, studies have shown long-terms fans were happier in their youth and better adjusted in middle age compared to their non-fan counterparts."
Perham continued, "Another finding that fans who were made angry and then listened to heavy metal music did not increase their anger but increased their positive emotions suggests that listening to extreme music represents a healthy and functional way of processing anger." - via LOUDWIRE