Violent videogames glorifying antisocial characters could increase teenage gamers risk of criminal and other risky behavior like smoking and alcohol use, a US study said Monday. These adult-rated games also affect teenage users self-image, according to the study by Dartmouth College researchers published in the Journal of Personality and Social Psychology. A previous Dartmouth study published in 2012 had already found that such videogames could incite teens to drive carelessly. Other studies have linked violent videogames to adolescent aggressiveness and violence.