When Kirsti Rodrigues logged onto her MySpace account one day in 2008, she was mortified by what she found: a blog entry titled "Fakes and Flakes" that a friend had written about her after a fight and had posted for the world to see.

That was the first time Rodrigues, then 18, thought she experienced a panic attack.

"It affected me badly," the Kailua, Hawaii, resident said. "This past summer was bad because I was depressed thinking about it."

Youths who are the victims of cyber-bullying are more likely to be depressed than the bullies themselves, a new study by the National Institutes of Health suggests. The findings differ from studies of traditional in-person bullying, which have found that kids who both bully and are bullied are likely to be depressed, according to the researchers.

Cyber-bullies  spread hostility and scorn using cell phones or computers, whereas in-person, traditional bullies use verbal taunts, physical violence and social exclusion, the study noted.

"Before, people would only have to deal with bullying at school," Rodrigues said. "Now that the Internet has made its way into people's lives, it makes it easier and more available to cyber-bully 24/7."

In the study, researchers asked 7,500 students from 43 countries, all of whom were in sixth through 10th grade, whether they'd been bullied, whether they had bullied someone, and whether they felt sad or had symptoms of depression in the last 30 days.

Frequent victims of cyber-bullying reported much higher levels of depression than the admitted bullies did, and slightly higher levels of depression than the students who said they'd been both a bully and a victim, according to the study.

A big reason for the depression could be that word spreads faster and more easily online: Blog posts, comments and e-mails can be written anonymously and readily copied and pasted, said researcher Ronald Iannotti, a staff scientist at the National Institute of Child Health and Human Development.

Once made, such posts may survive indefinitely.

"Cyber-bullying goes on, it persists," Iannotti told MyHealthNewsDaily. "So not only does it happen the first time you've seen it, but you know it's still out there circulating."

Unlike traditional face-to-face bullying, where there is a limited number of witnesses, cyber-bullying can have an audience of hundreds or thousands of online bystanders. The anonymity of the poster can add to the victim's stress because there's no easy way to get the person to stop, Iannotti said.

"You don’t know who the audience is, and you don't know who the bully is," he said.

That's what happened to a high school junior in Gilbert, Ariz., last spring  Jazmine said she signed up for a website (formspring.me) that allows people to ask questions publicly and anonymously to get to know friends better. But instead of asking innocuous questions, her peers used the anonymity of the site to spread false, hurtful rumors, she said.

"There was a rumor spread about me saying that I did things with this one kid," said Jazmine, who asked that her last name not be used. "As soon as it happened, I was bombarded with comments like 'Oh, the whole school hates you,' and 'Everyone knows what you did.'"

Jazmine deleted her account immediately, but many students at her school had already seen the posts.

"It got bigger and it took a few months to… blow over," she said. But the incident still follows her: Just a few days ago, more than a year after the first posts, other students approached her to ask if what they heard about her was true.

The effects of cyber-bullying make it important for parents to stay involved in their teens' lives. Parental involvement is the single factor that seems to protect an adolescent from becoming a bully or the victim of a bully, said study researcher Jing Wang, a research fellow at the National Institute of Child Health and Human Development.

The study, which appears today (Sept. 21) in the Journal of Adolescent Health, follows some cyber-bullying incidents that ended in tragedy and drew nationwide attention, including the suicide of a 15-year-old girl in Massachusetts in January after she was taunted both in school and online. In 2006, a Missouri teenager killed herself after being bullied on MySpace by her former friend's mother.

The researchers said they will next try to determine if teens who are depressed are more likely to be cyber-bullied, or if being cyber-bullied is the cause for depression.

This article was provided by MyHealthNewsDaily, a sister site to LiveScience.