I've been diagnosed with both bipolar and Asperger's syndrome. They interact in really strange ways, especially socially - when I'm depressed, I isolate, I'm standoffish, flat affect, restricted interests, I seem more autistic. When I'm manic, they're all still there, but I'm so hyped up that I'm much, much more social, and less reserved, less standoffish, definitely less flat.
I've also studied theatre so long that at least when I'm normal or manic, it's possible for me to hide it from most people. The only people who guess I have Asperger's before I tell them are people who are pretty familiar with it. But because of my presentation, some of the psychiatric professionals I've seen disbelieve the diagnosis, so much so that I wonder about the diagnosis myself. I know I'm definitely bipolar, with autistic traits. Maybe I'm broader autism phenotype.