This has changed alot for me over time. So I'm not sure if I ever really had bipolar but the diagnosis of "other bipolar" was suggested to me earlier. And the changes happened without medication so I'm even less sure if it was bipolar. But...I did have mixed episodes a lot. So it is why I had that "other bipolar" diag. I no longer have the episodes. I no longer have acute depression episodes or crises either! I called the mixed episodes crises too. I just have a baseline of "low" now that I had before the first manic/mixed episode anyway. Working on that. But to answer the question, the acute episodes would last half a day or a day. Very acute ones. I had an extreme depression episode once (called double depression I think) for 3 weeks but that was due to a bad event. The mixed episodes would be anywhere from 1-2 days to 2 weeks (incl start and finish). And the "low" baseline I've had for nearly 20 years