As in all things, it's not so much of a "yes/no" diagnosis, but a spectrum. But the range they can give you in the spectra (ADD/ADHD) seem to be pretty tight.

From my experience, they asked me about past behaviour, current behaviour, and some questions to probe my ability to keep track of the conversation. It was the questions about my past and current that really shocked me. They were asking if I did specific things that I just thought was "me being weird' but are actually /extremely/ typical of people forming coping mechanisms for different symptoms.