These are my theories on why some of us suffer from depression and the implications for us as men.

Body. As someone who occasionally suffers from depression I have spent some time working out my triggers and coming up with some theories to explain them.
I am not an expert but I do have an interest in evolutionary psychology which asks the question what is something for?
So what is depression for apart from inspiring suicide, bad poetry and Nick Cave albums.
My crackpot theory is this. When we were more tribal or cave dwelling there were periods of time when we had to endure periods of low activity. Winter, autumn, the herds have moved on, whatever it might have been. We would retreat to our tents, adobe huts, or caves, and wait it out.
Testosterone is a chemical that makes you want to be active and moving. That is great in summer, but if you are in a time of low resources you don't need that active guy anymore. He eats too damm much and can be a danger to himself, hunting prey in winter. I think depression is a kind of hibernation. It makes people less active, reduces testosterone levels and makes people less prone to spikes of emotion. YMMV. when I get really depressed I want to sleep and hide in my room. Sounds like hibernation to me. I think depression is more prevalent because we are tricking our bodies into thinking it is winter. We stay inside, away from natural light and are sedentary. Our brains say, "uh oh, winter time. Turn down the metabolism. Have some depression." Implications for me. To avoid my flavour of depression I need to convince my body it is summer. Eat well. Fresh fruit and vegetables are summer food. Get natural sunlight often. Get up early. Be active ( in summer mode), avoid other people in winter mode. They could be a psychological trigger and push you into winter mode (depression). My theory might be crap although seasonal affective disorder is recognized as a mental condition. Even if it is, following those steps is not going to make your life worse.