You never know what a person has gone through. I know many people who were raped as kids, abused, had parents going through rough divorces, had parents who were alcoholics, addicts, etc. Sometimes kids have faced more 'real problems' then some adults.
Remember, kids are humans too, they feel. If in your mind's eye their problem is minute, in theirs it could be the whole world.<br />
A problem is a problem, no matter how you look at it.
I think kids have always gone through depression, it's just that technology had made the current generation soft and more open about it.
If they are being abused, they will become depressed.
And? Ever heard of child abuse and etc.?