I wasn't diagnosed bipolar until I was 25. I'm kind of weird and only loosely fit the criteria. When I do get a rare hypomania it only lasts for 24-48 hours, never the 4 days they use in the DSM. I'm depressed most of the time and sometimes I get really low. I think I'm like an ultraradian cycler or something. It's the only explanation I have. I can wake up on top of the world and that evening or the next day feel hopeless and down. It's lousy. I think it gets worse as we get older. Mine seems worse now than in my 20s.