Because 7 years old is borderline too young to even make a depression diagnosis, and that kid's going to have his brain chemistry altered and essentially be addicted to a drug that he'll have to pay for for the rest of his life.
O cool. Do you have any appointments I can book for my kid?
If this guy has a non chemical cure, I'm all for it. In fact I'm actively researching children psychologists to stave off the meds as much as we can, the problem is that 99% of psychologists are quacks, so choosing them is tough.