TikTok has gained a fair bit of fierce criticism over the last few months; the China-owned social media app is the most popular on the market, with tens of millions of users and downloads. That includes, of course, teenagers.

Apart from the debate over espionage and data privacy, TikTok is a highly addictive app. We covered more on that here, but recent studies show that it’s not just the amount of time spent on the app that is troubling, but the specific kinds of content young people are ingesting every day. Julie Jargon writes in the Wall Street Journal,

Data privacy, though, might be less worrisome than the power of TikTok’s algorithm. Especially if you’re a parent. A recent study found that when researchers created accounts belonging to fictitious 13-year-olds, they were quickly inundated with videos about eating disorders, body image, self-harm and suicide.

-Julie Jargon, TikTok Feeds Teens a Diet of Darkness – WSJ

TikTok’s algorithm feeds teens a steady diet of videos on suicide and body image depending on which videos are liked. Jargon continues,

The Center for Countering Digital Hate, a nonprofit that works to stop the spread of online hate and disinformation, tested what teens see on TikTok. Last August, researchers set up eight TikTok accounts to look like they belonged to 13-year-olds in the U.S., the U.K., Canada and Australia. For 30 minutes, researchers behind the accounts paused briefly on any videos the platform’s For You page showed them about body image and mental health, and tapped the heart to like them.

TikTok almost immediately recommended videos about suicide and eating disorders, the researchers said. Videos about body image and mental health popped up on the accounts’ For You pages every 39 seconds, they added.

Jargon recommends that parents become more aware of what their children are viewing online. It clearly is having a massive impact on the mental health of teenagers. Better yet, perhaps they simply shouldn’t have TikTok until at least high school. That’s the view of social psychologist Jonathan Haidt, who has studied extensively the effects of social media on Gen-Z.