First off, I'mma say it's hard to have any sort of reasonable verdict on the subject at hand without reviewing the material, so I can't say whether or not you're tackling the subject manner in a "mature" manner that would portray the subject matter at hand in a good way. But as per what I understand about depression is that it can be tackled from a couple different directions or explored in a number of different ways. From being something like a "illness of the soul" in the way the Japanese understood it before they were finally made to recognize Depression as an actual disease and not a fictitious abstraction, to a lack of vitality:

[youtube]https://www.youtube.com/watch?v=-eBUcBfkVCo[/youtube]

But like most things, you may not honestly know the depths of the illness or the scope of the malady until you live it. So if you think you need to explore the depths of something you've never faced to such a scale you needed or experienced in its truest form the best you can do is read and read and read. This excludes the daily experiences of anxiety and shit in the modern world.

-------------

But, on the topic of "hair trigger" topics: I too sometimes enjoy delving into that field. Or something close. I don't go out to be edgy or directly tackle the same subjects as you list. But lately I have been exploring making other people sad for dramatic entertainment. And in doing so, and exploring this what I find is a good tool is to explore and use the opposite dichotomies of happiness and sadness. Since in the natural dualistic nature of things you can't often have one without the other, and there's a little bit of one in the other. And having one is helped by having the other since it establishes a supposed status quo that helps to put the one in a proper light.

So it's not often enough to write a LE TRAGIC BACKSTORY PAY ATTENTION SENPAI backstory. At some point the character will have have to of had a happy period or found happiness and beauty in something to cling to. This is an achor to not only keep the character alive, but also serves as something that can be returned to to liven up the character to pose a proper comparison between what the character is and what the character was, could be, or should be.

For my own projects experimenting with this principle (and I will preface this from this point forward by saying it involves cartoon ponies) I wrote and drew up a [url=https://www.derpibooru.org/1113916]mock journal for one of the children characters[/url] of MLP and her mother according to long-standing head cannons.I then shipped the mother with the fandom's least favorite character and [url=https://www.derpibooru.org/1126030]then killed the mother.[/quote] But ending it on a low note would be sour, and to put it back into perspective for the readers, [url=https://www.derpibooru.org/1126051]brought it back into life with the mother's death and the past recognized and it all laid out in perspective of life[/url].

It's something as I continue to play with to build off of the skeletal narrative told through a mock child's diary and to reinforce it and move ahead with things what I come up with as a conclusion is that things - really, all things - need to be dealt with tact and balanced reason. You can't just force everything into it because it's sad, because you go so far and it'll become impossible to grasp or seemed forced. As much as we'd like to claim it is, life is not one long continuous episode of one single thing (ie. depression) and there's plenty of parallel things going on which we may ignore or become blind too depending on circumstances.

And in my opinion and in conclusion, if you're setting up a character to have a shit backstory so they can be sad, mopey, and depressed there needs to be a comparative point where they were happy, there should be something for them to cling to or recognized as something to that effect, and there should be a conclusion where they "recover" or everything comes to its own end so the character develops through their disease. This seems to be where people end up failing at, they make depressing characters to be edgy and dramatic yet there's little to no work to see things out to and end or to change because what these characters ultimately fulfill is to be an empty attempt to grab attention.