Using Facebook and other social networking sites can negatively affect teenagers’ treatment for substance use disorders, a new study suggests.

Researchers administered a 20-question survey to 37 teens who were receiving substance abuse treatment at a behavioral health center in Los Angeles. Most reported marijuana as their drug of choice, followed by Ecstasy and methamphetamine, Psychiatric Times reports.

Almost all of the teens engaged in online social networking, with the majority using Facebook. While 44 percent of the teens said they posted drug-related content on the sites, 94 percent said their friends did, and 97 percent said their social networking friends used drugs.

Lead researcher David Tran at University of California, Los Angeles said 66 percent reported that drug-related content on Facebook, Twitter or MySpace made them want to use drugs. “While these are preliminary data, they indicate that online social network sites may negatively influence treatment outcomes for adolescents,” he said at a news briefing at the American Psychiatric Association Annual Meeting, where he presented the findings.

Only 22 percent of the teens posted or accessed recovery-related content through social networking sites, the study found. “Our next step is to implement an intervention at the substance abuse treatment center to use along with their treatment plan,” Tran said. “We are planning to establish a Facebook group as an intervention. In this way, we can engage youth and enable them to access educational information anytime and anywhere.”

He said he does not recommend blocking teens’ access to social networking sites, since they will most likely find a way to use them.