Posting constant status updates on Facebook FB, -0.89% may be annoying for others, but a new study finds that oversharing on the world’s most popular social network is also a sign of loneliness.

More than 79% of the users who describe themselves as “lonely” disclosed personal information, such as their favorite books and movies, compared with less than 65% of other users, according to a new study published by researchers at Charles Sturt University in New South Wales, Australia, which will appear in the July issue of the journal, “Computers in Human Behaviour.” The study analyzed Facebook postings of more than 600 women — half of them described themselves as “lonely.”

What’s more, nearly 98% of the lonely users shared their relationship status publicly on Facebook instead of restricting it to just friends, and they even publicly shared their home address online, according to the study’s authors, associate professor Yeslam Al-Saggaf and lecture Sharon Neilson from CSU’s School of Computing and Mathematics. People who don’t explicitly state that they’re lonely on Facebook (though some might be) tend to share more about subjects like religion and politics, the study found.

“It makes sense that the people who felt lonely would disclose this type of information,” Al-Saggaf says. “They want to make it easier for others to initiate contact with them, which may help them overcome their feelings of loneliness.” But over-dependence on social networks as a social outlet can also lead to what some doctors call “Facebook Depression,” according to a 2010 report, “The Impact of Social Media on Children, Adolescents and Family,” by the American Academy of Pediatrics.

Rich DeNagel, 45, a former high school teacher who’s currently on disability, says he went off Facebook for several months because it made him feel depressed. “For the most part I feel Facebook is a lonely experience. You don’t often see people putting out that they’re going through a hard time,” he says. “There’s a lot of social pressure to show that everything’s great. It’s a never-ending quest to be interesting and intellectual and unique, and strive to prove something to the world. You can’t just be yourself.”

Want to see someone teach a grandmother to use Facebook?

Al-Saggaf and Neilson’s study isn’t the first to link over-sharing on Facebook and emotional distress. In 2012, Larry Rosen, professor of psychology at California State University and author of “iDisorder: Understanding Our Obsession with Technology and Overcoming Its Hold on Us,” analyzed 800 Facebook members and tested them for a range of psychological disorders, and found those who most often “like” other people’s activities on Facebook are more likely to show symptoms of “mania” and “compulsivity.”

On a happier note, having more Facebook friends may also be a predictor of fewer symptoms of mild and major depression, indicating that people who are popular online are well-adjusted in real life too, research by Rosen found last year. But it cuts both ways: Social media can be a way of gaining virtual empathy — “but also make you feel that everyone else’s life is better than yours as though you have to show your best self and gain admiration through ‘likes’ and postings,” Rosen says.

While Facebook behavior might be a sign of loneliness or even exacerbate those feelings, it’s unlikely to cause it. Christopher Shea, 48, who is studying for a Masters degree in social work at New York University, is a big Facebook fan. “I get a charge out of the likes I receive on my posts,” he says. “I suppose it’s tied into self-esteem and feeling noticed. I wouldn’t be surprised if there was even a slight dopamine response when those ‘likes’ start pouring in.” But it may also be good for those who are shy: “It’s a safe space in which to engage.”

Younger Facebook users typically have a larger number of friends than older users. Some 27% of Facebook users aged 18 to 29 have more than 500 friends in their network, while 72% of users age 65 and over have 100 friends or fewer, recent research by Pew Research Center found. Among adult Facebook users, the average number of friends is 338, and the median number of friends is 200. Put another way, half of all Facebook users have more than 200 friends, and half have fewer than 200.

DeNagel, who has a higher than average 500 friends on Facebook, says the social network is useful for keeping in touch with people with whom he might otherwise have lost touch, but he still treads carefully with his online footprint. “It makes me feel more lonely,” he says. “I don’t want to take a selfie every day and change my picture or tell everyone what my inner thoughts are because maybe I’m a bit more private. But I’m sure there is a group for people who are lonely and depressed, if I went to look for it.”

Other articles by Quentin Fottrell:

Why teens are rebelling against Facebook

Facebook tackles its most annoying posts

How to game your Google search results

How job recruiters screen you on LinkedIn