‘I was told I’d never be good enough. That my death would bring everyone happiness.’’

“‘you put yourself in that position’ is the sentence that came out of my parents mouth when i told them i had been raped for the past two years.’’

“I’ve never really said this before ... I was sexually assaulted’’

Those are the anonymous words of some US teenagers who are struggling with trauma and depression. A report released last month by the Centers for Disease Control and Prevention, which analyzed 2021 data from the CDC’s biennial Youth Risk Behavior Survey, revealed a heartbreaking outlook: Nearly 3 in 5 teen girls, or 57 percent, said they felt persistently sad or hopeless. It’s the highest rate seen in a decade and double that of teen boys. About 1 in 3 teen girls reported seriously considering dying by suicide, a percentage that’s up nearly 60 percent over the last 10 years. Almost 20 percent of girls said they experienced sexual violence during the past year.

Overall, 42 percent of all teens said they’d felt so sad or hopeless that they couldn’t engage in regular activities, such as schoolwork or sports, for at least two weeks, a percentage that has risen by 50 percent in the last decade.

America’s teens are going through a mental health crisis. And one local teenager is doing something about it.

The harrowing comments you read above were posted on Breathe (BreatheSafeSpace.com), a website launched in December by Sophie Nystuen, a 16-year-old junior at Brookline High School. Nystuen wanted to offer a safe, therapeutic space on the Internet where teens could express themselves and unload their feelings and stress by writing public or private posts.

Nystuen’s initiative, which was featured in The Washington Post last month, offers a simple but notable counterpoint to the role that digital and social media play in teen mental health. With Breathe, she is effectively leveraging the benefits of this generation of youth’s tendency to be extremely online. Crucially, Breathe was created by a teenager as an antidote to the teen mental health crisis.

“I was going through a lot of stress and anxiety last year,’’ Nystuen told me in an interview. “And I created a Google Doc [because] writing is super cathartic. I could get everything out.’’ After a while, she said, she wondered, “how many people need some place where they could not only write whatever they wanted to, but also see people that they can connect with and relate to, and feel less alone?’’

So far, Nystuen said she has received about 60 public posts and 100 private posts. She screens all posts for “threats or derogatory terms’’ and any other key information that people might write in a post. For instance, “if someone said they were underaged and put their name, I am legally required to report [to police as a mandatory reporter] the person if they discuss topics like sexual assault or physical abuse,’’ Nystuen said.

The high school junior started advertising her website through dozens of fliers that she posted in her school and around nearby colleges. She also launched an Instagram account to promote it. “I think social media is a mix of quite literally everything,’’ she said. There’s the good and bad. She believes that social platforms like TikTok and YouTube play a role in the mental health crisis but “there are a lot more aspects that contribute to someone having anxiety or a breakdown.’’

Dr. Neha Chaudhary, a child and adolescent psychiatrist at Massachusetts General Hospital and the chief medical officer at BeMe Health, a mobile mental health platform for teens, agrees. “I see social media as one contributing factor among a sea of stressors that teens are facing right now,’’ she wrote in an e-mail. “Over the past couple of years, the world has gone through one big, collective trauma, and teens had some of their biggest supports — routine, structure, social connection with peers, and certainty — ripped out from under them.’’

For Nystuen, working on Breathe and going through the posts make her feel a little less alone. She also gets gratification from the feeling that she is doing something to help her peers. Breathe is only one remedy to tackle the underlying causes of the crisis — for instance, Chaudhary argued policy makers should advocate for making available to all teens some form of mental health support. To be sure, youth mental health is everyone’s responsibility. But it is heartening to see teenage-driven steps that confront the most basic question: Why are teens so unhappy?

Marcela García is a Globe columnist. She can be reached at marcela.garcia@globe.com. Follow her on Twitter @marcela_elisa and on Instagram @marcela_elisa.