I have four teenagers and work with dozens of others. For those young people I see every day, I can tell you where stress and unhappiness enters their lives.
It is true that social media can add stress, and some young people I speak to realise this and have made their own decision to limit their use of social media or even avoid it completely. However, social media is not the biggest cause of stress that I hear about.
At school, they are frequently assessed in every subject and their performance is measured against a hypothetical trajectory calculated by software. My daughter (Y9) works as hard as she possibly can, yet feels that what she does is never good enough, because she is still struggling to meet her targets. She cried at a recent parents' evening, and this is a young person who hardly ever cries.
The goalposts are constantly changing. My son (Y11) is about to take 10 GCSEs. 7 of his courses are new. The textbooks weren't published until after the courses had started. Other than one set of sample papers, there are no past papers to use for practise. In one of his courses, the way it was to be assessed was changed when he was already 75% of the way through the course. He spent 20 hours on a controlled assessment which he was tod would be 20% of the GCSE. Halfway through the assessment, he was told that it would count for nothing, but had to be completed anyway.
Part of my role at work involves supporting young people with mental health difficulties. For those with anxiety, the most common contributing factor they report is academic stress.
And this is before you add in the effects of poverty, family conflict/breakdown etc.