With their gated communities and phalanx of bodyguards, celebrities used to be almost unreachable for the average fan—unless the fan was prepared go to some seriously disturbing lengths. Now, thanks to Twitter, stars such as Justin Bieber and Lady Gaga are just a follow away—but that has given fans another outlet to express their sometimes unhealthy obsessions.

For many teens, just following a favorite star on Twitter isn’t enough. For them to feel validated, they have to get the object of their ardor to follow them, too—and that’s not easy to do. In an effort to get noticed, many fans, particularly starstruck teenagers, send 1,000 tweets a day (the limit Twitter allows) to a celebrity. Some obsessed users have multiple Twitter accounts, so when they hit Twitter’s 1,000-tweet limit, they can switch to another account and keep tweeting.

This tweet obsession has some experts worried.

“To me, my biggest fear of what it’s replacing,” says Dr. Marion Underwood, a clinical psychologist and professor at the University of Texas at Dallas. “If they do it too much, if they are spending many, many hours a day tweeting, texting, posting status updates, what’s it replacing? It’s replacing time on academic work. It’s replacing time on face-to-face interaction, and it’s replacing sleep. I think that’s what scares me more than anything. It’s not good for a person to go to someone’s birthday party and never look up from their phone because they’re on Twitter the whole time. It’s not good for that person’s relationships.” (The Atlantic)

Paul Asay has covered religion for The Washington Post, Christianity Today, Beliefnet.com and The (Colorado Springs) Gazette. He writes about culture for Plugged In and wrote the Batman book God on the Streets of Gotham (Tyndale). He lives in Colorado Springs with wife Wendy and his two children. Follow him on Twitter.