Growing up, my teenage friend group would frequently dive into mental diagnosis and personality assessments. This feels like a very common teenage thing to do and TikTok didn't invent it. At that age, you don't know who you are or why you do things you do and there's comfort in learning about this stuff. For that matter, it's a joke among psych students that you begin to diagnose yourself and your friends as you take abnormal psych.
Or maybe it wasn't a common thing for friend groups to do and mine was strange. We didn't have the WSJ to tell us.
I participated in this with friend groups, prior to the era of TikTok. I think it's actually an interesting exercise, since doing things like MTBI tests in a group—even if the results/outcomes are tenuous at best—it helps you start to understand and breakdown how different people tick.
"Personality tests" have been a thing for a long time. The difference here seems to be that we're talking about diseases and not just differences between people.
Or maybe it wasn't a common thing for friend groups to do and mine was strange. We didn't have the WSJ to tell us.