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Websites and blogs that support anorexia — known as pro-ana sites — have been widely banned online by the likes of Pinterest, Yahoo and Tumblr. For anyone who’s ever visited a pro-ana site, the reason is clear: the content exchanged in these online communities is often shocking. They use images of emaciated models and celebrities as “thinspiration” for vulnerable girls, and include frank discussions on the best methods for achieving extreme weight loss.

Anorexia is the most deadly of all psychiatric disorders, and pro-ana websites can be especially distressing to family members and friends of those who are suffering from it. But it is precisely because anorexia is so devastating — and so stigmatized — that such websites may be a boon to some of those who visit them. Like similar groups for addicted people who are not ready to give up drugs, they can provide a rare source of nonjudgmental support for people with eating disorders.

According to Daphna Yeshua-Katz, a doctoral student at Indiana University who co-authored a new study on pro-ana sites appearing in the journal Health Communication, a close look at these sites reveals certain benefits: behind the exhortations to achieve bodily perfection or to glorify an often-fatal psychiatric illness, there are communities of people, mainly women, who understand one another’s demons. These communities provide an anonymous, judgment-free place for sufferers to talk about their struggles with a highly stigmatized disorder for which few effective treatments are available.

(MORE: Defining Recovery in Anorexia — and Addiction)

For her new study, Yeshua-Katz interviewed 33 pro-ana bloggers. “Out of 300 bloggers we contacted, 33 were willing to be interviewed,” says Yeshua-Katz. She says that the highly controversial nature of the sites and the bloggers’ fears of their real identities being revealed kept many from participating. Because the sample was not random, the findings cannot be applied to all pro-ana bloggers, but they offer a rare insight into a hidden world.

“They were going online first of all to find support,” Yeshua-Katz explains, noting that having an eating disorder is a very isolating experience. As with drug addiction, people with anorexia typically cannot discuss their condition or their feelings about it with loved ones without immediately being challenged to change. “The Internet is a very good place for people to find support from similar others,” she says.

As one blogger told the authors: “There was no one in my life that I could speak to openly about what I was feeling and experiencing. I wanted to have a voice that I didn’t have to censor for fear of upsetting people I knew or having them judge me.”

The bloggers also saw their sites as a means of self-expression. “They wanted a venue where they could express themselves without judgment,” says Yeshua-Katz.

(MORE: Parents Allowed: Family-Focused Therapy Works Better for Teens with Eating Disorders)

While they used their sites to support readers’ intentions to stay thin, pro-ana bloggers were acutely aware of the potential dangers associated with the material they presented. “The people we interviewed were actively trying to reduce harm,” says Yeshua-Katz. “When you go to pro-ana blogs, the ones we looked at all used disclaimers before allowing entry into the site, saying [things like] ‘This blog contains triggering information'” and warning off children or people recovering from eating disorders.

However, about half the bloggers — all of whom were female — were in high school, barely out of childhood themselves. The rest were mainly in college; overall, the surveyed group had an average age of 20. Most had suffered from an eating disorder for about seven years.

One of the key criticisms of pro-ana blogs is that they fail to present anorexia as an illness, promoting it instead as a lifestyle choice — a dangerous message to young, impressionable girls. But only 9% of the bloggers interviewed characterized anorexia that way, with nearly three-quarters viewing it as a mental illness and the rest describing it as a coping mechanism. Meanwhile, efforts to keep young girls — or “wannarexics” as they are dismissively described — out of the sites were made repeatedly, but it’s unknown whether these hurdles are effective or may even make underage visitors more persistent.

Interestingly, nearly a fifth of the bloggers considered themselves to be in recovery from their disorder at the time of the interview. It’s not clear whether their recovery could have been spurred by their participation in pro-ana sites, or despite it, because the study wasn’t designed to look at the health effects of the blogs. But as with addiction recovery, there are pros and cons to being exposed to the “people, places and things” that might trigger relapse: early exposure could provoke slips, but avoidance only increases the power of these cues; when avoidance isn’t possible, it’s actually better to be desensitized to the cues by repeated exposure without relapse.

One of the few studies to look directly at the health impact of pro-ana blogs found that while people who viewed them were less likely to be in recovery than those who didn’t search online for information about their eating disorders, people who simply used Google or other ways of exploring the Internet to seek out such information were just as likely to be ill as those who read the explicitly pro-ana blogs.

(MORE: A Genetic Link Between Anorexia and Autism?)

Of course, finding community among people who are committed to engaging in self-destructive behavior can obviously reinforce an identity that involves avoiding recovery. Friendships forged in these groups may be perceived as being contingent on staying sick. “They go online to vent, and they find friends. But at same time they are aware that being a pro-ana blogger might encourage their eating disorder and those of other vulnerable young girls,” says Yeshua-Katz, adding that blogging “paradoxically actually adds another area of stress because now they have another thing to be secret about.”

Research on harm-reduction programs for addiction, such as needle exchanges for drug users or “wet houses” for alcoholics, does not find that these seemingly “prodrug” places prevent recovery. In fact, needle exchanges are often a key source of referrals into drug treatment. Users cite the nonjudgmental environment of these programs as one reason they feel safe enough to reach out for help and try to quit.

But unlike harm-reduction programs, the main goal of pro-ana sites is not to reduce harm, nor are they run by professionals, which leaves open the very real possibility that they can worsen users’ disorders. “I’m not saying it’s only beneficial or all bad; it’s a double-edged sword,” says Yeshua-Katz.

Nonetheless, she does not support banning pro-ana sites. For one thing, she thinks that it’s technologically impossible. Second, what would the bans really accomplish? Virtually all of the thinspiration images used on pro-ana blogs come from mainstream fashion and gossip websites and magazines; the content isn’t unique. “I think we need to provide [people with anorexia] with better ways to lead them into recovery online,” she says. Perhaps the anorexia and addiction online worlds can learn from each other.

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Maia Szalavitz is a health writer at TIME.com. Find her on Twitter at @maiasz. You can also continue the discussion on TIME Healthland’s Facebook page and on Twitter at @TIMEHealthland.