My grandfather who fought in war against Nazi Germany as an adolescent and experienced what nowadays would be considered as major traumata, told me that in the Soviet Union the diagnosis of depression was unknown. And that despite millions of killed dear ones, torn apart families, devastated infrastructure.
Back in the day, people had to suck it up and deal with the problems and the still existing social community bonds certainly provided support.
I feel that clinical depression is a problem of luxury. First, giving a name to a psychological state, that deviates from the norm, devolves responsibility from the subject and this is only exacerbated by providing the subject with pills that supposedly "fix" the problem.
Secondly, nowadays, most Western people do not have to deal with existential threats for survival. Humans 20,000 years ago did not have the chance to develop "depression" - either they solved the problem at hand or they died.
Today, we have many life problems whose (non-)resolution will not alter our survival chances. This leaves us room to develop and dive into extreme emotional states. We often have too much time at hand. The young generation, especially, does not know how to deal with adversities, since their parents have given up on letting their children grow up with restrictions, instructions, principles and values.
Facing adversities, lacking the means to deal with them, not having a strong and independent will to acquire those, in conjunction with doctors and psychologists having learned to characterize prolonged grief and sadness as depression and the availability of antidepressants, certainly let the diagnosis of depression flourish.
That said, I would never take antidepressants myself: because they mess with your neural wiring in unforeseeable manners and they are neither treating the underlying cause nor the symptoms.
I have a friend who allegedly suffered from a sudden episode of major depression because he felt (his own words) like a loser when he started comparing himself to his girlfriend (who wanted to marry him). The doctors saw themselves forced to treat him with drugs to get him out of his extremely apathetic state. Although that brought him back to "normality", the drugs induced a series of subsequent manic-depressive episodes, him gaining weight, having constantly shaking hands... A disaster.