Researchers say that half of teen MySpace sites include references to sex, drug use, or other high-risk behavior, with 41 percent of sites studied featuring drug-related information, Reuters reported Jan. 6.

In one study, researcher Dimitri Christakis of Seattle Children's Research Institute and Megan Moreno of the University of Wisconsin looked at randomly chosen profiles of 18-year-olds on the social-networking site MySpace and found that 54 percent of profiles available to the public showed information regarding high risk behavior.

The researchers sent messages to 95 adults ages 18 to 20 whose profiles showed risky behavior, warning them of the risks of sharing such information on the internet and providing a link to a website with information about sexually transmitted diseases. A second study found that many of the subjects subsequently removed references to sex and substance abuse or limited viewing privileges on their profiles.

(How can I keep my teen safe on MySpace?)

Such an intervention "really provides the opportunity to reach millions of potential at-risk teens and try to modify their behaviors or at least prevent them from disclosing them to the entire world," Christakis said, adding that teens should protect such information from potential sexual predators as well as future employers and universities.

The studies were published Jan. 1, 2009 in the Archives of Pediatric & Adolescent Medicine.