And as for anxiety, I think our modern urban lifestyle far increases our anxiety levels compared to our ancestors.
The human body was not meant for the world we live in!
Anyway, only recently have men started talking about andropause. The main reason it is still a controversial subject is because men's reproduction systems don't completely shut down, and because the process can sometimes be much slower. However we still go through many of the same hormonal changes and it is rather unnerving.
I think we have only the barest minimum of understanding of the chemical processes that control and regulate our bodies. Jumping on the production a single chemical as the root of all issues is a little ridiculous sounding to me. Especially in light of all of the recent discoveries about our microbiome. (gut bacteria)
It is an insanely complex interplay. Over the next few decades I'm sure our understanding will increase exponentially.
It would indeed be very interesting to compare the spectrum and balance of hormones and microbiome structures from 100 years ago to those typical in the contemporary human. It could be different because of lifestyle and environment, or it could be self regulating, and nearly the same (the perceived differences being cultural).