I think this is the best song you've ever worked on. It may be because I have gone through depression in my life. Interestingly though, I don't even see that much about depression in this. It seems more like confusion. There are different styles in here that I guess are supposed to represent madness. It may not have much variety, but it's still awesome.
It's just that it does such a great job of building itself up. It makes you think about loneliness, which is definitley a part of depression. It's starting to seem sound with some of the later sounds. I am glad you did such a good job of capturing emotion. Of course, madness isn't that much about depression anyway. The vibes are great.