Teenagers who play mature-rated, violent or risk-glorifying video games may be more likely to engage in a wide range of deviant behaviors, according to a recent study.

Previous studies have found that violent video games increase adolescent aggressiveness, but researchers at Dartmouth College found that risk-glorying video games could cause teens to engage in a wide range of deviant behaviors beyond aggression, including alcohol use, smoking cigarettes, delinquency and risky sex.

More generally, such games - especially character-based games with anti-social protagonists - appear to affect how adolescents think of themselves, with potential consequences for their alter ego in the real world.

"Up to now, studies of video games have focused primarily on their effects on aggression and violent behaviors," Professor James Sargent, co-author of the study and pediatrician, said in a statement. "This study is important because it is the first to suggest that possible effects of violent video games go well beyond violence to apply to substance use, risky driving and risk-taking sexual behavior."

For the study, researchers conducted a longitudinal nationwide study involving more than 5,000 randomly sampled American teenagers who answered a series of questions over the course of four years in telephone interviews. They looked at a number of factors, including the playing of three violent risk-glorifying video games (Grand Theft Auto, Manhunt, Spiderman) and other mature-rated video games.

Based on the findings, such games are associated with subsequent changes in a wide range of high-risk behaviors and suggest this is due, in part, to changes in the users' personality, attitudes and values, specifically making them more rebellious and thrill seeking. Effects were similar for males and females and were strongest among the heaviest game players and those playing games with anti-social protagonists.

"With respect to playing deviant video game characters, we feel it best to follow the admonition of Kurt Vonnegut in Mother Night: 'We are what we pretend to be, so we must be careful about what we pretend to be,'" Professor Jay Hull, the studies' lead author and chair of Dartmouth's Department of Psychological and Brain Sciences, said in a statement.

The findings were recently published in the American Psychological Association's Journal of Personality and Social Psychology.