I think it partly has to do with what level of security is around you, I don't live in a place (Denmark) where I have to solve that many other people's basic needs so I can optimize further up in the pyramid of needs.
I get that. But financial freedom, at least for me would go a long way in terms of not being depressed. Once you beat depression, then you can function well and take care of your health and security. then do the same for others.
Not being happy all the time is not a mental illness or a problem, nor is it synonymous with depression.
I didn't mean for it to be sad. I just don't get why the "self" is so important. Isn't it natural for a person to at least attempt to be about others?