Every month, we’re keeping you informed on the latest studies and research in our “Not My Teen” blog series. Today, we’re looking at how content viewed on online social networks can impact the smoking habits and alcohol use among adolescents.

Use of online social networking among teens has skyrocketed over the past decade. Sites like Facebook and Twitter have and continue to grow in popularity because they allow users to easily communicate with friends who are both nearby and far away. With teens being so easily influenced by their peers, a photo shared or a comment made online carries a lot of weight. These activities also allow adolescents to transmit their attitudes, exhibit their behaviors and create lasting impressions.

Until fairly recently, little was known about how the content teens digest online affects their behavior offline. To gain a better understanding of the specific influence of adolescent social media activity on smoking and alcohol use, researchers at the University of Southern California conducted a longitudinal study of over 1,500 10th-grade students.

In the first phase of the study, researchers surveyed students on their use of tobacco, alcohol and social media as well as that of their friends. About six months later, they asked the students to repeat the survey. By comparing the responses between surveys, scientists discovered that adolescent exposure to online displays of friends partying significantly increased the risk of tobacco and alcohol use. In fact, students who viewed party photos posted by and commented on by their friends were themselves 20 percent more likely to start drinking and smoking. They also found that youth who reported having friends who drink were more likely to use alcohol. Interestingly, youth who didn’t report having friends who drink were also at greater risk of using tobacco and alcohol after viewing photos of such activities online.

The researchers believe that these results may be caused by a “biased normative perception of risk behaviors.” That is, when adolescents view photos of friends drinking and partying, they develop the impression that such behaviors are common. The more photos they view, the more popular the risky behaviors seem. In adolescence, a critical time in the process of forming an identity, teens are especially likely to model the behavior of their peers.

Thomas Valente, one of the researchers behind the study, told NPR that parents should be aware of their teen’s social circles and teach them how to interpret content they see shared on social networks, “so they [teens] don't come away from these experiences thinking 'Oh my gosh, if I don't go out partying and drinking heavily every weekend I'm not going to be popular!'”

Parents, you can find advice on talking to your teen and monitoring their behavior online here.