The 4 days duration in the DSM is only there for practical reasons (it's a cutoff), not actually because it has much true diagnostic value, which is also why you can be diagnosed with bipolar without fitting the four-day criteria if your symptoms fit with ultra-rapid or ultradian. Duration is not really as relevant as that (you have to think of the duration in it's proper context, I think especially it should be compared with the intensity of the symptoms and to what degree the moods are reactions to something that could normally elicit a similar mood), but they maintain that it is still practical in trying to figure out what the best course of therapy is. "They" are the DSM people, and their decision to keep the cutoff duration is controversial. There is, I know, some controversy around the ultra-rapid and ultradian categories of bipolar, but as far as I know it's not one of the most controversial issues (ultradian is more controversial, but very rare). Almost everyone agrees that these people are bipolar, and the controversy is more about how they should be labelled. If the DSM is getting rid of the ultra-rapid label they will surely give these people another label, and that label surely is not BPD (or anything else non-bipolar). There are also some prominent people who hypothesize that BPD is in fact a bipolar spectrum illness. The heritability and the genes involved with BPD and bipolar are comparable, the suicide rate is very high for BPD but not as high as bipolar. The prognosis is worse for people who have rapid cycling (that means their illness is probably more severe than yours). I don't think questioning their bipolarity is very constructive.

It can be hard for me sometimes to recognize that hypomania is hypomania, but after an hour or two I usually have it figured out. When I come down it is very obvious. My normal moods that are reactions to something are nothing like my short-lived hypomania, but I consistently underestimate the severity of my hypomanic symptoms, at least for a while until I can look back and see how I've been and what I've done. So while I have difficulties figuring out what is a symptom of hypomania and what is not, I do not confuse normal moods with hypomania. I've never had a normal mood that is anything like my hypomania is nowadays. The depressed state is easy for me to recognize, but I score very high on tests for depression so I don't know if it's the same for other people.

I thought I was an ultra-rapid cycler, now I think I'm in a mixed state. I've had almost no unmedicated relief for two years or something like that. I've had six months of medicated relief, i.e. sleep, drowsiness and dullness.