My diagnosis was interesting:

My therapist convinced me to take medication for my ADHD. She said, "I'm not trying to push medication on you, but medication can really help. You should see a psychiatrist and try them out. If you don't like them, you can always quit." So, I signed up for my first pdoc appointment.

When I got to the appointment, my pdoc asked, "Can you describe your concentration problems to me?" When I proceeded to explain them, he said, "Uh huh. And how's your mood been?"

We had a VERY lengthy interview about my symptoms. He asked all sorts of questions and it lasted 1 hour.

At the end of the interview, he said, "You're bipolar." I said, "What?" He said, "You're experiencing mixed mania right now." I was flabbergasted.

I didn't believe the diagnosis, so I sought 2 professional opinions. Did 2 neuropsych evals. One of them said bipolar. The other said bipolar and ADHD.

The neuropsych evals were intense. I did a full IQ test, had my memory and attention assessed, given the MMPI personality test, a bunch of mood disorder questionnaires, etc.. I also interviewed with the psychologists themselves and explained my symptoms to them. So, it was more than just "ticking off boxes" on a questionnaire. I had to explain things so that they could be sure of my diagnosis... if that makes sense.

I highly recommend getting a full neuropsych eval... You don't have to do the IQ test, although the IQ test is kind of cool because it reveals a lot about your personal strengths and weaknesses. Sometimes those weaknesses are due to disorders, too... so it can help with the diagnosis process. However, I don't think an IQ test is "necessary" for an accurate diagnosis... and it might even be expensive depending on your insurance.