Teens and young adults are self-diagnosing mental illness on TikTok. What could go wrong?

“I love when people say you don’t have ADHD,” @KatieSueHue says in one video, giving her audience a “we know better” look.

As she dances to cheerful music, her list of ADHD symptoms flashes onscreen: “Coming off bubbly, blunt and quirky.” “Reliving every convo I’ve had and regretting what I said.” “New hyperfixations every month.”

By early November, the video had 1.7 million likes — Smith’s among them. “This kind of sounds like what I’m dealing with,” Smith thought.

As the country’s intense mental health crisis meets a shortage of mental health providers — and TikTok burrows ever deeper into our lives — experts are worried that vulnerable people with real illness are being led down sometimes destructive paths, and that even many who aren’t ill are being seduced into thinking they are.

It’s easy to think of TikTok as just a platform for short, lighthearted dance videos or viral lip synchs or cinnamon challenges.

But over time, its algorithm has become famous for figuring out what users are interested in, and then relentlessly pushing video after video on the topic — a practice that sends people “deep into rabbit holes of content that are hard to escape,” according to a 2021 Wall Street Journal investigation.

A TikTok spokeswoman pointed the Globe to a blog post on the topic that says the company is “testing ways to avoid recommending a series of similar content — such as around extreme dieting or fitness, sadness, or breakups. . . .”

On the positive side, the TikTok videos (or postings on other social media sites) can give people insight into themselves and propel them to seek professional help, experts say. If you look for it, it’s even possible to find content from actual mental health experts, and all this attention on mental health is bringing what was once a taboo subject into the light.

But too often, experts say, suggestible people mistake having one or two symptoms with having the disorder itself.

“If I were to go through the DSM” — the Diagnostic and Statistical Manual of Mental Disorders — ”and take a tiny snapshot of every diagnosis, we would all relate and self-diagnose,” said Alex Chinks, a licensed clinical psychologist in Needham. “A symptom of depression is fatigue. Well, I was fatigued all week.”

Corey Basch, a professor of public health at William Paterson University, recently led a study that looked at 100 TikTok videos with the #mentalhealth hashtag. Collectively, the videos got more than 1 billion views, but even more stunning — and extremely concerning — were the volume and intensity of the comments, she said.

In a video about cutting that suggested instead snapping yourself with a rubber band and dousing your wrist with red paint to mimic blood, for example, commenters were thankful for the suggestion.

“I wish someone would jump on and say, ‘I’m a mental health professional, and when my patients want to cut themselves, we work through ways to identify more adaptive behaviors in times of distress,’ ” Basch said.

In videos about a scenario in which a particular person makes you depressed, she said, “an army arrives in the comment section to validate. ‘This person is toxic or awful,’ even if the person is their mother.”

To go on TikTok and search for mental health disorders is to find yourself in a world with seemingly endless seductive videos. They’re mainly hosted by random strangers and people with enough followers that they’ve become known as “influencers,” who detail symptoms while they dance or mug for the camera, and Adele or the latest viral hit plays in the background.

Here’s one from the #Autism genre: “Things I didn’t know were my autistic traits,” the onscreen message reads, as a telegenic woman moves to the music and bats her false eyelashes.

“Listening to the same song on repeat!” is one sign of autism, viewers learn as she smiles. “Struggling to respond to messages” is another.

Some of the symptoms detailed in the mental health videos — including listening to a song on repeat or struggling to respond to messages — are almost absurdly general. But people who are trying to understand themselves might find that a “lightbulb goes off for them, even if it doesn’t completely provide the answer,” said Lovern Moseley, a psychologist at Boston Medical Center.

“People want to feel like they are part of a community, or they are looking for something to explain why they don’t fit in or why they behave in a certain way.”

Indeed, Deborah Offner, a clinical psychologist in Newton, recently treated a college student who was struggling with feelings of insecurity and vulnerability and who “learned” from TikTok that she had an “anxious attachment style,” Offner said.

But there was no evidence of “anxious attachment” — which is a clinical categorization based on the nature of a child’s early attachments to caregivers, said Offner, author of the forthcoming “Educators as First Responders,” a teacher’s guide to adolescent development and mental health.

“In my opinion, she was just tired of connecting with people at parties and then having them walk by her the next day as if they didn’t know her.”

TikTok self-diagnoses can be harmful because they can prompt people to give themselves inaccurate labels, said Jessica Brunner, a licensed clinical social worker.

“It’s not a good way to go through life,” she said. “It can completely alter how someone thinks about themselves. ‘Hello, my name is OCD,’ or ‘Hello, my name is depression.’ ”

In a statement e-mailed to the Globe, a TikTok spokeswoman said, “We care deeply about the well-being of our community, which is why we continue to invest in digital literacy education aimed at helping people evaluate and understand content they engage with online. We strongly encourage individuals to seek professional medical advice if they are in need of support.”

Smith, the woman who suspects she may have ADHD, has made an appointment to discuss it with her doctor. But no matter what the professional diagnoses, TikTok’s algorithm has already spoken.

“I just got an ad for an app where I can pay $80 a month for some kind of random [ADHD] assessment,” she said.

If you or a loved one need help, the state maintains a list of crisis hot lines (https://www.mass.gov/service-details/crisis-hotlines).

Beth Teitell can be reached at beth.teitell@globe.com. Follow her @bethteitell.