How is 'adult add ' diagnosed? I went to a local psychiatrist today for the first time. I've had symptoms most of my life; he didn't diagnosis or treat me.

Ask the evaluator. It's possible he didn't think you have adhd. According to dsm-4 (official diagnostic manual) you'd need to have signs of it by age 7. If you didn't have it in childhood, it's not adhd. It's also possible he needs more data from you or others to make the diagnosis. In my opinion, he owes you an explanation of his thinking in any case. Psychiatry shouldn't be mysterious.
Adult ADD. Thorough personal history, family history & mental status exam should guide to proper diagnosis.