Self-harm blogs shelter in a dark, desperate corner of the Internet that few of us will ever see. But 14-year-old Anouschka, a baby-faced blogger, has lived here for months, collecting photos of slashed wrists and razor blades, reading grim, adolescent poems about death and loneliness — and meeting the first community of friends that she has ever really had.

Self-harm blogs are little understood outside the largely female, teen community that reads and writes them. To others, they can be disturbing: sites dedicated solely to cutting, suicide or eating disorders, replete with stomach-turning details, high-contrast photos and song lyrics from depressive teen bands. While self-harm content has been banned on Tumblr, one of the most popular blog platforms, since February 2012, almost 200,000 bloggers still use language related to eating disorders and self-injury, according to SimilarWeb, an analytics firm that tracks aggregate Web data.

That makes the blogs a serious public health crisis. Or a profound resource for lonely, isolated teens — depending on whom you ask.

“I think this whole area of ‘harm blogs’ is the most contentious area, with both academics and clinicians, as regards whether the Internet is more of a force for good or harm in health care,” says John Powell, a senior clinical researcher of primary-care health sciences at the University of Oxford. “There is no consensus on where the balance lies.”

For Anouschka, Tumblr has always been a force for good. She lives in the Netherlands, and is identified by only her first name. She described her life to this reporter in a series of e-mails and provided a photo of herself holding a sign with her Tumblr URL to verify her identity.

A pretty, articulate high teenager who loves books and the boy band One Direction, Anouschka nevertheless struggled to fit in at school, where classmates called her fat or left her off their party invite lists. At home, she fights often with her parents and fumbles through sessions with the therapist she has been seeing since her father first noticed the cuts on her arms. Before Tumblr, she could tell no one about her depression — but on her blog, she found a like-minded audience of 1,700.

“It’s just that everyone feels the same. I know they’re not going to judge me for self-harming,” she said. “It’s nice to know that you can tell your story without being judged.”

But the issue isn’t that simple, experts caution. The bonds that form between self-harm bloggers can reinforce their feelings and behavior, convincing them that cutting or eating disorders are normal, even healthy. Some blogs spread misinformation about treatment or dangerous information about how to inflict self-harm more effectively. Because teenagers’ social judgment lags behind that of adults, they can be easily swayed by the material they see online — and easily convinced of its accuracy.

For recovering self-harmers, the blogs pose another threat: Pictures and descriptions of cutting can “trigger” relapses, says Shannon Barnett, a pediatric psychiatrist at Johns Hopkins Children’s Center. In her group therapy sessions with teenagers, Barnett doesn’t even allow patients to mention their scars.

Instead, she tries to talk patients through the reasons they self-harm, helping them understand that their feelings are valid and understandable, and then teaching them a set of emotional and interpersonal skills.

“In order to change the [self-harming] behavior, you need both: the validation and the change,” Barnett said. “That’s the problem with these sites — people find them very validating, but they don’t have the change. It can make kids feel pretty hopeless.”

Last year, that fear led several networks, including Tumblr, to ban content that glorifies or promotes self-harm — an ambiguous standard the site is still working to pin down, said Tumblr’s communication director, Katherine Barna. On the recommendation of the National Eating Disorders Association, Tumblr also began surfacing a ­public-service announcement with help-line numbers to users who search the site for such terms as “suicide” and “thinspiration,” a popular hashtag for eating-disorder blogs.

Eighteen months later, however, there’s little to suggest the ban has worked. Self-harm blogs still flourish on Tumblr, with as many as an estimated 197,200 discussing mutilation and eating-disorder terms, according to SimilarWeb. (Barna declined to discuss the number of self-harm blogs on the site or whether the ban had reduced that number.)

A recent study of French eating-disorder Tumblrs by researchers at France’s Telecom ParisTech and the University of Greenwich suggested the ban hasn’t actually silenced self-harm bloggers, but simply made them go underground — where it’s more difficult for advocacy groups and other healthier, more hopeful voices to reach them.

That leaves both social networks and clinicians with a difficult contradiction to resolve: how to help teens with depression, eating disorders and other mental illnesses harness the benefits of social media but not the harms.

NEDA, the eating-disorder advocacy group, and To Write Love on Her Arms, an anti-suicide organization, have some ideas. Both have tried to stake their flags in social media spaces that were once dominated by pro-harm bloggers. TWLOHA, an organization particularly popular among women of high school and college age, has amassed nearly 250,000 followers on Tumblr with its mix of feel-good testimonials and artsy, Tumblr-friendly illustrations. NEDA has recruited several of its writers from Tumblr’s nascent anti-harm space, where blogs such as “The Love Yourself Challenge” post bright, uplifting messages — and slap them with hashtags including “anorexia” and “cutting,” so that self-harm bloggers such as Anouschka see them.

NEDA also recently launched its own personal social network, a Web site called Proud2BMe, that invites people suffering from eating disorders to share their stories in a more regulated environment. The organization has lobbied many sites, including Tumblr and Facebook, to clamp down on self-harm policies.

“We’re trying to counteract some of these unhealthy messages and provide an alternative,” said Claire Mysko, who oversees NEDA’s teen outreach. “We want to connect people with other pro-recovery users, because we understand that it feels good to be understood. But if the message keeps you entrenched [in self-harming], that outweighs the benefits of connecting to others.”

Those benefits, some researchers argue, could prove key to future treatments for depression, both in adolescents and adults. Clinicians in Canada and the United States have begun experimenting with direct outreach to prospective patients on social media. Benjamin Van Vorhees, the head of general pediatrics at the University of Illinois Children’s Hospital and the leader of a multimillion-dollar study on Internet-based depression intervention, thinks that a “managed” social network could go even further: He envisions a primary treatment program that combines phone- and Internet-based counseling with moderated, peer-to-peer networking. Trials suggest such a model could protect at-risk teens against depression before it’s even diagnosed.

“They want more flexibility and more of a social media model,” Van Vorhees says of the at-risk teenagers in his study. “They want more interactions with others.”

Unfortunately, those innovations may come too late to help such teens as Anouschka: Van Vorhees expects it will take years for ethics boards to catch up with teens. In the meantime, the 14-year-old blogger has no one. Last month, Tumblr moderators deleted her blog for violating the self-harm policy for the second time.

This time, she says, she’s not sure she’ll bring it back.