I have stressed triggered hypomania apparently, a lot of things stress me more maybe than your average NT. 

There are many types of bipolar it is a spectrum as much as ASD is a spectrum.  I geuss you got to remember that (at least in the UK) HFA/Asperger's is a new diagnosis (1994) chances are many people were diagnosed Bi-polar etc without recognising the underlying HFA/Asperger's.  Besides they have not done enough research to know what is exactly going on with the brain that causes all these issues.  I swear I have had undiagnosed bi-polar 11 for sometime.  I had a long depressive period after uni, did not seek help, I smoked weed and drank to deal with my mood.  I know this is a big thing in my mum's family, hey most of the women are bipolar and the men alcolholics go figure.