I don't think there's a single answer to this as it is a multi facade problem. However I have been wondering is how much the global decline of testosterone levels in men has been contributing to this?

Speaking personally, I had no idea my testosterone levels were low until my wife and I started having arguments over sex, I know it sounds ridiculous but I had close to no libido as a man in his 30s. Even when I was younger I had no desire for sex and just thought it's "the way I am". My wife and I are both Catholics so naturally we don't attribute much value to sex however after a series of frustrating fights, I did some research and figured I should get tested..

When my results came back, I was only at 10nmol/L! After repeating the test multiple times (3 times, before 9AM), my baseline was established at 10-12 nmol/L..

This was _very_ surprising as I have a healthy BMI, exercise regularly (weight lifting + cardio 2x a week) and eat well..

Anyway after being refused by public doctors for TRT (since I'm in the "normal" range), I finally had it. I went to see a private urologist and he immediately put me on HCG + TRT and it has been incredible.. It has been 5 months now and my mood is much better, my libido is like a teenager and I have more energy.

Moral of the story: check your testosterone levels gentlemen!