The revelation that the number of children being prescribed anti-depressants has QUADRUPLED in a decade should really set alarm bells ringing. Children as young as four - FOUR, for Christ's sake - are being prescribed mind-altering drugs to allay their symptoms of "depression".
No doubt all the social scientists will be coming up with various "causes" and "solutions" - most of which will be completely wrong as must of the stuff they come up with usually is. What they almost certainly won't acknowledge is that the biggest cause of unhappiness in children is that so many of them are growing up in single parent households without the presence of a father.
The best solution to the problem is to encourage marriage, encourage married people to stay married and discourage parenthood outside of marriage. Having children should not be seen as a meal ticket as it is for so many.
Tighten up the ridiculously lax divorce laws, give preferential treatment to the traditional married family through taxation and housing and any other means possible, refuse to accept that all relationships are equal (they aren't) and stop pandering to the social engineers who have spent fifty years ruining this country.