Anderson, C. A., & Bushman, B. J. (2001). Effects of violent video games on aggressive behavior, aggressive cognition, aggressive affect, physiological arousal, and prosocial behavior: a meta-analytic review of the scientific literature. Psychological Science, 12 (5), 353-359.

Abstract:  Notes that research on exposure to television and movie violence suggests that playing violent video games will increase aggressive behavior. In this study the authors examine the role that violent video games have on aggressive behavior. A literature search was conducted on PsychINFO for all entries through the year 2000. A meta-analytic review of the video-game research literature reveals that violent video games increase aggressive behavior in children and young adults. Experimental and non-experimental studies with males and females in laboratory and field settings support this conclusion. Analyses also reveal that exposure to violent video games increases physiological arousal and aggression-related thoughts and feelings. Playing violent video games also decreases prosocial behavior (PsycINFO Database Record (c) 2004 APA, all rights reserved)