I'm literally reading van Gogh's diary right now. I'm gaining huge insight into the man's brilliance from it. It's actually not a diary, but a collection of his letters illustrated with the paintings and drawings that those letters refer to. I think I understand better what he was dealing with, and how he saw the world. He was a really beautiful person, which I didn't expect. I'm also trying to be a painter, and it brings both serenity and despair, so I think I understand what you're asking.
I don't think it's necessary to suffer to make great art or music, but in the case of van Gogh, I do think his mental condition changed the way her perceived color, light and darkness. I don't think he could have seen the world the way he did if he had been healthy. Of course, this is just my own theory, based on personal experience with mild depression, and not based on fact.
I can't really say if I'd be as creative if I hadn't suffered some trauma in my life. I think maybe I would be, but the outcome would possibly be happier. I put a lot of myself in my art.
I find creating let's me focus and the stream of negative thoughts that is sometimes relentless quiets. I usually feel euphoric when I finish something, then the thoughts start telling me it's actually not good. My solution is to try to maintain a certain level of creativity, and to practice meditation when I need them to shut up. Haha.
I have been reading some of your posts as well, and just want to say I really wish you all the best. I know you're going through a tough time. It will change. It always does. Try to remember that, and maybe try meditation. It does help.
Lynn