Some people can work just for material benefit to themselves and their families. However, eventually that juice runs out because money is just not useful beyond a point. Depression is a first world problem, generally. Why is it that people who are materially better off than most of their peers in the last century become depressed?
The key, it seems, is to find a goal that is higher than immediate selfish interests of the individual or family. This might even mean staying in your current situation but just realigning "why" you are doing it to something higher. It is very hard to find an unselfish person who is depressed, unsure about what to do or unhappy in general.
The goal makes all the difference.