I deal with this garbage from "norms" too. My brother will do this silently by shaking his head when I express certain feelings or ideas even on things that have nothing to do with my illnesses. It really gets to me and pisses me off. How dare him! I can't *stand* for someone to tell me that something is "...all in your head." To me that is a way of dismissing it because they don't want to be bothered with it.
I also hate when someone insinuates that your perception of something isn't real or didn't really happen that way and that it just 'seemed' that way to you because you're paranoid. As if being schizophrenic means that everything we perceive is 100% BS! I can tell reality from delusion just fine because I've learned how to but, that's another story. Yes, I can definitely see why it's so insulting to be treated this way as if what you're dealing with doesn't really matter or that you have no idea what you're talking about or something is wrong with the way that you think. Sorry for the rant. I just understand a little *to* well I suppose. My way of dealing with it is to just shake my own head internally as I look at them with a sort of pity. Sometimes it seems that we are the normal ones and they are the ones with a sickness, doesn't it?