My PTSD did cause dramatic mood shifts but after years of treatment for the PTSD the longer duration of highs and lows were there and my secondary Dx of MDD was changed to BP.
It's easier to see thevBP shifts now that the PTSD is under control but I wasnt Dx BP first and I think that's the question you are asking. If those with rapid mood shifts were Dx BP but the shifts might be caused by something else?