This is an almost Buddhist thing for her to say and it is compatible with all religions I’m familiar with, and with atheism – in the sense of, letting go of ego / grasping / striving and seeking contentment rather than the ever-nebulous “happiness”, being selfless and other-centered. Of course it, like anything, can be taken too far, into self-abasement and neglect and passivity.
She’s also correct that one can do the right things for the wrong reasons – once can serve a god simply to escape a feared punishment and not out of any sort of desire to elevate their character and be kind to others. Christianity in particular often loses sight of that in my experience. It lacks humility.
As with many such issues, there isn’t a single cause for depression. There are a host of psychological and social reasons. To the extent the current / upcoming generation is “more depressed” I would say it’s because they have no hope for themselves and no sense that their efforts in life amount to anything. Sure, in some cases what they want might be unrealistic or selfish, but – how many intelligent and self aware 25 year olds seriously think they are going to retire comfortably with a gold watch one day, and in the meantime, live in safety and prosperity? Most are shambling through life just barely getting by in a world that wants the last farthing of their strength in exchange for little more than just enough to stay alive and keep working. To me, that’s the real crux of the matter, to the extent it can be condensed into a paragraph.
That in turn is largely a function of rich fucks hoarding the fruits of everyone else’s labor, and creating a society where there’s no permission or will to level the playing field, and no one but the uber-wealthy have any real rights or worth. And in this country, a huge swath of Christianity is right on board with that, often in very un-self-aware and self-defeating ways. And THAT in turn is because of the authoritarian nature of the belief system, the idea of groveling before an all-powerful monarch and serving him without question.
So it’s great that your mother has found a measure of wisdom that works for her, but she’s not fully thinking it through.
For example, in what way is the triumphalist message of evangelicalism NOT teaching people that god is in your corner, has you in his back pocket, will protect and care for you because you belong to him by faith and not for any reason of personal worthiness but just simple trust? What does that do but make credulous children like I once was think that if they just have faith that it will happen, they will be safe and happy and blessed and protected?
The Bible is chock-a-block full of such “promises”. It depicts god like a mother hen, and his children finding safety beneath the shelter of his wings. It even invites people to “taste and see that the Lord is good”, to just try him out – believe him for things and see if the very windows of heaven aren’t opened and you aren’t showered with his largesse, “shaken down, pressed together, in good measure”.
So Christians are contributing to your mother’s perceived problem at least as much as anyone else. They are fostering sky-high expectations in a world that, in fact, doesn’t give a fig about individuals or their needs except in the limited circumstances where it transactionally benefits the system in the short term.
Finally there’s the whole romantic fantasy that special relationships should be easy, even effortless – when the reality is that everyone is just another imperfect asshole and once the bloom is off the rose it’s a lot of hard, often buzz-killing work to foster a mutually healthy relationship and keep your head above water. So not only doesn’t God have you in his back pocket, your life partner and immediate family often don’t consistently have that sorted on your behalf, either. That whole thing goes back at least to 11th century Arthurian legends and fantasies of pure yet unrequited courtly love, so I can’t really blame it on religion, apart from how religion often condones and reinforces it. My point here is just that to whatever extent young people think that they will find happiness in finally meeting “The One” just sets them up for failure there, too, and there are few things more depressing than a jilted or disappointed lover. I think that has reached new heights as society doesn’t have a consistent framework that informs people of their proper roles and supports them in it – and Christianity’s patriarchal system never was anything but lipstick on a pig there, anyway.