Or, when the context is right, just ask, "hey, did you ever get diagnosed as ADD?" I once had a close friend ask if I had [other syndrome], and my answer was "

Or, when the context is right, just ask, "hey, did you ever get diagnosed as ADD?" I once had a close friend ask if I had [other syndrome], and my answer was "I have all the symptoms but don't care to seek a diagnosis." It was a very polite way to inform me, and a polite way for me to say that I was happy living my life the way I want to live it.