I love this song, it sounds exactly like I sound. While bi-polar is a true disease, I think the song is describing people who cry out "it's not my fault I'm [insert label here]. Using it as a crutch. I've been through the wringer in ways that make people's jaws drop and I refuse to be beaten by anyone or anything.
So when people say, "I've got PTDS" or whatever, hey, we all have something most likely. Labels are a lame excuse. Take your medicine!