Not that I dress outlandishly but I definitely have my own style that stands out - starting with some pretty funky hair. The more manic I am the more defined this is. Usually it is in the granola-eating theme.
The ironic thing is that I do have a self-esteem problem and am always concerned about what people think of me and my appearance. I guess that dressing the way I do is a way of trying to control that. If I figure I am going to stand out anyway, I might as well be in charge of that. I dunno if this will make sense to anyone but me.
One thing though is that I am bipolar and the my hypo/manic I get the more 'out there' becomes my appearance.