As long as there’s been an internet, there have been people using it to indulge in emotional oversharing. But for Elyse Ash, a digital marketer in Minneapolis, the dog photos and memes that once filled her timeline have increasingly been replaced by posts that seem a little darker, a little more serious. At least a few friends were posting that way enough that she was starting to worry.

The tricky thing is that these were people she hadn’t seen or spoken to in years—not a little brother or a best bud, but fringe friends: old acquaintances and former coworkers. So she posed the question on Facebook: “What do you do if someone you (kind of) know is displaying strong signs of mental illness / anxiety / depression on social media?”

Social media keeps us connected to people far after we’re no longer in each other’s orbit, when the friendship has fizzled and we’re not close, geographically or emotionally. When you hardly know someone, how do you figure out what’s a mental health crisis and what’s your run-of-the-mill Vaguebooking?

And to what extent, in either case, is it your responsibility to intervene? Ash has a husband, an infant, and two jobs—how much emotional investment and energy is she expected to give? “For me the relationship is a huge part of it,” she says. “What am I willing to give emotionally to this person based on our relationship, how close I feel to them, how concerned I am? It feels like some weird formula that I haven’t figured out.”

First things first, there are a lot of ways people try to get support from social media. “There’s some research showing that people who have low self esteem tend to post more negative things,” says Erin Vogel, a social psychologist and researcher at the University of California, San Francisco, who studies social media and well-being. “They might put up a status about something terrible that happened in their day and be looking for support.”

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But she says people are more likely to engage with posts that come from a place of positivity: When people post more negative things, they’ll generally get less of a response, Vogel says. That can make them feel more isolated and depressed; the posts continue to sound sad, and ultimately, people interact less in an Instagram Oroboros of feelings. “This can be a problem, because a lot of people with lower self esteem, who are more shy, or have social anxiety, use social media because they want to get support from other people in a way that doesn’t feel threatening,” she says.

So what should you, as the consumer of a sad post, do?

One thing you shouldn’t do is worry that you’ll somehow make things worse by intervening. “I think social media provides kind of a missed opportunity to reach out to people who maybe do need a lot of support and don’t feel comfortable asking people in their everyday life for it,” Vogel says.

“It can be very valuable and important to intervene in these cases,” adds Jacqueline Nesi, a research fellow in Brown University’s Department of Psychiatry and Human Behavior, who studies the role of social media in adolescent mental health. She describes a phenomenon called the “bystander effect,” which is the idea that people are less likely to intervene in emergency situations when other people are present.

“On social media, this may be amplified—we are less likely to intervene because we assume that others who, for example, are more qualified or know the individual better, have already done so,” Nesi says. “This diffusion of responsibility can prevent the individual from getting the help and support that they need.”

But while reaching out is a good idea, reaching out in a super public way might not be.

“I think what you don’t do is send a message everyone can see saying, ‘Hey, I think you’re depressed and you should get help,’” says Crystal Clark, an assistant professor in the psychiatry department at Northwestern University’s Feinberg School of Medicine. That, she says, can be off-putting.

Instead, if you decide to address it, do so with a private message. And again: You don’t need to worry that this is somehow going to make things worse. “If you ask them directly how they’re doing—‘Are you depressed? Are you suicidal?’—that’s not going to make them kill themselves,” Clark says. She recommends normalizing it with a message along the lines of “Some of the things you said sound like something I’ve heard someone who was depressed say,” and having some resources on hand if you can. “You don’t have to be an expert to pull an article off of Google about depression,” Clark says.

Even the experts admit they don’t always react when they see a woe-is-me post slide across their screen. “I totally get why people are hesitant to interact with it, especially if it seems like something really serious,” Vogel adds. You don’t want to get sucked into someone else’s problems, and no one can emotionally support the legions of online “friends” they’ve accumulated over the years. “A lot of us don’t want to get involved if we feel like we can’t really support that person.”

That’s why, if you’re unable to offer your time or emotional energy but are truly concerned, she recommends alerting the social media site to the post. On platforms like Instagram, Facebook, and Tumblr, you can report content not for violating terms of service, but from a place of concern for suicide or self-harm.

In the end, Ash did end up reaching out to a peripheral friend to see if everything was okay, and she opened up about her divorce. But she didn’t volunteer her friend services either. Just: I’m sorry. You’re a strong person. I hope you can find the support you need.

“It was basically just acknowledging, ‘I see your pain and I see what you’re going through,’ but not volunteering to take it on as my project,” Ash says.

Which is absolutely okay. It’s not your responsibility to take on the burdens of every random person. “Even reaching out a little bit—just validating what they’re going through in some way, even if it’s just a small comment—that can be helpful,” Vogel says.