Several studies have suggested that Facebook, Myspace, and other social media sites have created a new form of peer pressure, exposing young people to risky behaviors they could be tempted to emulate.

The eternal struggle to keep young people away from bad influences has moved to a new frontier, a new study suggests: A research organization said Aug. 24 that teens who regularly log on to Facebook and other social media sites are considerably more likely to smoke, drink, or use marijuana than teens who don’t visit the sites.

The study has ignited debate over whether, and to what extent, social media sites are responsible for amplifying the peer pressure many teens already face offline.

The National Center on Addiction and Substance Abuse at Columbia University in New York found that teens who spend time on the social networks are likely to see images of their peers drinking or using drugs—images that could help to convince them that substance abuse is a normal, acceptable activity.

“We’re not saying [the influence of social media sites] causes it,” said Joseph Califano, the center’s chairman. “But we are saying that this is a characteristic that should signal to [parents] that, well, you ought to be watching.”

The findings are in keeping with a new wave of research into how social networks might affect teen decision-making. Several studies have suggested that Facebook, Myspace, and other social media sites have created a new form of peer pressure, exposing young people to risky behaviors they could be tempted to emulate.

That conclusion rings true to some teens and parents.

“The internet puts it in your head,” said Dana Cichon, 16, a junior at Bartlett High School in Illinois. “You think everyone else is having more fun than you.”

But some experts warn that the research, like social media sites themselves, is still in its infancy, and that the correlation between social networking and teen substance abuse could be disguising more relevant risk factors. Others contend that bad influences in the real world are much more potent.

What many experts agree on, though, is the importance of parents keeping tabs on their children’s internet activities.