Having directed this to my teenaged younger sibling (he is intelligent and expressive) he explained in his view, teenagers have a poor prognosis for their career prospects and are aware of this. Technology allows them to be aware that life doesn’t look good for them, that they cannot look forward to retirement, to a stable long term career, that the amount of education and debt they will need to accrue is ever-increasing, that their success in this society will rely on using and stepping on others who will now have less as a result, if not in their own community then in the international stage. He attends one of the best schools in the nation and he believes most of his peers feel the same pressures both of their career prospects and their place in the greater international stage and all the things that are wrong with it that they cannot change because they cannot be in a position to change with any sense of ease (e.g. to have enough money to buy jeans not made via human exploitation requires an amount of success that feels as if it is becoming rarer,and even then how do you help people who cannot afford them to avoid exploiting other humans)

All in all, I think a growing awareness of the worlds problems and their individual struggles to be in a position for themselves is a pretty good reason for teenagers to feel more anxious and depressed.