Ok to talk about eating disorder?

<p>in the common application, there's a part where you can write additional information. well, i had an eating disorder for most of high school and thats a big reason why my grades arent as they should be. the thing is, i never had it formally diagnosed, i just went to a counselor, so should they want to see documentation, i couldn't provide it. should i still go ahead and write about it or just not write anything at all?</p>