I am an adjunct college teacher. I imagine this is standard at most schools now -- in the syllabi for all courses, there is a statement that the school abides by the ADA and that reasonable accomodations are available for any disablity. I always make it a point when I get to that section in my first-class lecture every semester to say "And if anyone needs to discuss that with me, see me after class." When they do (I have had deafness, vision, psychiatric and other issues raised by students) I simply tell them that I will work with them and that I too have a chronic condition, which I name and explain briefly. It always works best to deal directly with the instructor in my experience. It is also important to keep the term "reasonable" in mind and ask only for what you truly need, like understanding if you need to leave class. If you are in a situation where you expect to need to miss more classes than normal, it is a good idea to get a letter from your treating physician going in that certifies your condition and explains that it may on occasion preclude you from attending. The one thing that frustrates me is students who miss a lot, never contact me and offer no explanation until it is too late to salvage the semester. Forewarned is forearmed.