That's so what I was trying to get at!

Bipolar can be ultraradian without comorbid BPD.
Bipolar can be ultraradian with comorbid BPD.

Bipolar episodes can in fact be triggered - it might not happen as quickly. I certainly know that if I spend a few weeks feeling overwhelmed/busy/stressed out that I'm going to either end up in a depression or a hypomanic episode. Same with I've even read a lot on here how people can induce their own manias by pulling all-nighters.

BPD happens to result in triggers probably having a bigger effect, and quicker. So what might take weeks to trigger me into an episode might only take a day or part of the day to trigger someone with comorbid BPD into an actual bipolar depression/mania.

I think ultraradian cycling without BPD is probably the most rare, but it's certainly out there. And until the docs figure out a sure-fire test to go "yep, you've got bipolar!" then there's absolutely nothing to prove it one way or another!