Only a couple points I'll make:
1. Mental health issues leading to suicide, esp in middle aged men, is not some "recent" phenomenon -- when I was growing up in the 70's and early 80's I knew two kids whose fathers committed suicide. I would be interested to know what the stats say about how much more frequent it is.
2. To me, and just speculating here, I think the biggest thing that has changed is all the "stuff" that we think we have to do to live a normal life. The term "rat race" was probably coined in about 1950, but back then it just meant the daily grind that people (mostly men) had to go through from 9 to 5 as part of their job. Now we've created so many demands on our time and attention that just weren't there before and we all have this constant feeling of being overwhelmed by life.