Meds--provide unfair advantage for students or help them function as well as students w/o ADHD?

I am a fulltime graduate student diagnosed about 2 years ago, but ADHD symptoms for quite a while prior to diagnosis and starting on meds.  Over the past two years I've been on a variety of meds in different dosages to try to find one that will best help with symptoms.  In completing a request for accommodations from the school such as permission to take a written exam in a room with less noise and distractions and allowing an additional amount of time to complete assignments as needed.  The Dean of Students expressed concern that this may give me an unfair advantage although he did approve the accommodations.  I recently read somewhere that there are some who believe that meds for ADHD also provide students an unfair advantage.  Any comments please?