I can't say for sure is causing the crisis in teenager, since I don't have one, and haven't been one since the Clinton administration. However I have a hypothesis.

I have seen a decline in mental health among my peer group, myself included. One common thread is an existential dread. Climate change, the current state of political discourse, the pandemic, the declining middle class, the raising costs of medical care, out of control education costs, and so on. It just leaves you with a feeling that you are screwed and there is nothing to do about it.

Teenagers are pretty aware of what is going on in the world, probably more now than ever. All this plus the normal teenage problems, and new problems like cyber bullying. This is just too much for someone who hasn't had time to build their coping skills.