It can be difficult to sort out co-morbid disorders. Usually when you have both what ends up happening is medication treats the big swings (the bipolar) and the little ones are all that's left and can be lessened with extensive therapy. If medication does nothing, it leads practitioners wondering if it's drug resistance or only BPD not bipolar. In addition, a big tip-off to bipolar is the highs of the disorder- the euphoria doesn't happen with borderline. Euphoria feels like a drug. Energy bouncing all over the place bubbly laughing talking fast not sleeping not tired etc.

Doctors used to lean toward bipolar but question whether BPD played a role because I was abused. However, once I was on the correct medication pretty much all my symptoms were gone, which ruled out borderline. I barely need a psychiatrist or therapist these days. I've been fairly stable for three years.

Another factor to consider is that BPD lessens or remains the same over time and Bipolar gets worse, untreated, over time.