Does anybody knows about Hormonal Depression? My friend was 3 months pregnant, and happily married though...?

Why here is a depression involved when the hormones dropped? Is it connected to our emotion? our brain? I'm confused!
Answers:

i'm 12 and i obligation minister to!?

The Thyroid affects chemical neurotransmitters and hormones. The body have a complicated loop.so when hormones drop or rise afterwards neurotransmitters which affect depression also drop or rise..that is to say the especially central of it.

the thyroid, not the brain...