I used to be diagnosed with Borderline PD and PTSD but once the PTSD was treated it became clear that I had BP as my mood shift were more episodic even though I am also a rapid cycler. BPD and BP can be difficult to distinguish and many have both. Perhaps I did have Borderline PD and the treatment dealt with that too? Who knows, but I show no signs of it now. However the PTSD rears its ugly head at times causing me a lot of grief.