It seems as though you have tried to tell her and as you say, she just doesn’t listen. Do you want to preserve the friendship? Is it of value to you? If it is, I think I’d try to tell her again. Perhaps write her an email or a letter telling her how you feel and explaining you’re writing because she a. hasn’t listened to you in the past and b. has dismissed your concerns and blamed your feelings on ADD. If she chooses to dismiss your feelings again, I’d start making other plans and being unavailable to spend time with her.