I was told by my pdoc, who I trust, that the way most professionals diagnose bipolar is that they question it. They match the symptoms that you describe to the DSM - IV and then they write it down and then try to disprove it. She said that if you respond to the medicine and feel better then you have a better chance of having bipolar, but the professionals can never be totally sure. I imagine that trying to get an answer right away is not easy. I had already been diagnosed with bipolar, but we didn't know what form it was taking. It took my pdoc a year and a half to come up with my diagnosis. Bipolar 1, rapid cycling with mixed episodes.

Here's the rub, That diagnosis can change because it is an opinion and not a medically proven fact. The whole thing is so subjective and that's why it takes so long to get clarity about it.