Comment: It's funny, but I just watched a group of high-school students waiting for their school-bus near my house as I drank my morning coffee.  There were about 10 teenagers there, none of them spoke to each other, most of them had ear-buds in, and all of them were staring into their phones.

Is it any surprise that many of them start to feel depressed?  I was depressed watching them!  Are these drones our future?

I would add to your list of potential root-causes the fact that most of these kids were put in day-care since they were babies and now spend all of their free time alone in their bedrooms with their phones/laptops.  This is social isolation.