I went to a private school all through elementary, middle school, and high school.

I went to very easy elementary and middle schools and I skated by without even doing anything really. So it wasn't until high school that all of my psychological issues came to light.

In high school, I had extended time on tests/quizzes/exams, separate proctor (In a quiet room), preferential seating, and some other things that I didn't make use of. I also was given extra time and separate testing area for both my SATs and my ACTs.

I am about to start college but I have registered with the student disabilities office and should be getting the same accommodations for my college exams.

I will say though that many schools want not just a copy of your official documentation of diagnosis but also record of you using the requested accommodations. If you had an IEP or a 504 plan, that will usually suffice as documentation. However since I went to a private school, I had to get my own psychological/learning disability evaluation.

Oh one more thing- if you are wondering about college accommodations, each college usually lists their procedures and available accommodations on their website. Usually under student services or disability services. Whether they approve you for those accommodations is a different story, and each school has their own way of determining eligibility, but at least you could see what accommodations you might be able to receive.