I've cycled a few times in a day. I didn't think it was possible until it happened to me. I thought they must just be mood swings. Oh heavens, they weren't. Thank goodness it hasn't been that rapid since last spring. My bipolar swings really unpredicatibly with no patterns right now. I hate it.

I suspect that 7 years of antidepressants caused my ultra and sometimes even ultradian rapid cycling.