Lots of texting and social networking may be tied to physical and mental health problems in adolescents, according to a study presented at the American Public Health Association's annual meeting. When a group of researchers at Case Western Reserve University surveyed students on their texting and social networking habits and tested them for risky behavior, the heavy texters and networkers were much more likely to have higher rates of substance use, thoughts about suicide, and were more obese and stressed than those who had more moderate use or abstained completely.

As mobile texting and social networking sites like Facebook and Twitter continue to grow in popularity, the researchers began wondering if heavy engagement in these activities coincided with health problems or maladjustment. They surveyed 4,257 students in an urban Midwestern school district about how often they texted and how much they used social networking sites on school days, and also had them take the Youth Risk Behavior Survey.

19.8 percent of teens reported "hypertexting," or sending more than 120 messages a day, while 11.5 percent of teens were "hypernetworking," spending more than 3 hours a day on their preferred social network sites. The authors found that the hyper-texters and -networkers were more likely to be minority students, female, and come from a lower socioeconomic status.

The hyper-texters and -networkers also tended to engage in much more at-risk behavior: higher levels of sexual activity with more sex partners, smoking, and drinking. They also were more likely to be obese and display a tendency toward eating disorders. As if that weren't enough, they had more stress and suicidal thoughts; they also got less sleep and felt less safe at school.

On the bright side, the survey found that almost a quarter of students engaged in zero texting (22.5 percent) or social networking (22.2 percent), and that they likewise had better health. Still, the correlation between health and time spent staring at friends' communiqués says nothing about which causes they other, if there's any causal relationship at all.