I suffered with this disorder long before I knew what it was and was able to analyze it correctly. I've only been REALLY paying attention to my patterns for a few years. I can look back and clearly recognize severe depressions and mania in my past, but I don't have enough insight to recall how I transitioned.

Now that I've been paying close attention, here is what I feel happens for me. My hypos start out mild and sometimes stay reasonably mild. I do not recall ever waking up in full blown mania from a depressed or stable state. (Not saying it hasn't happened in the past, but I don't recall it ever happening) I transition from mania, into a more agitated depression (a scary place to be) and progress into deeper and darker depression. If I'm perceiving my patterns correctly I seem to go through transition phases. I have went from manic to depressed overnight or even in the same day, but it starts as an agitated depression and moves into a near comotose type.