I actually read a book that made a similar claim, although I can't remember the title right now. It essentially said that depression as we know it is an illness

I actually read a book that made a similar claim, although I can't remember the title right now. It essentially said that depression as we know it is an illness for the contemporary world for the reasons you list. However, it made the point that there were "different" mental health problems in the past, which had to do more with the conflict against the more rigid social structure -- same but opposite to how today we suffer from the lack of direction that you describe well.