I copied this out of an article online....

According to Dr. Friedel, director of the BPD program at Virginia Commonwealth University, there are two main differences between BPD and bipolar disorder:

1. People with BPD cycle much more quickly, often several times a day.

2. The moods in people with BPD are more dependent, either positively or negatively, on what's going on in their life at the moment. Anything that might smack of abandonment (however far fetched) is a major trigger.

3. In people with BPD, the mood swings are more distinct. Marsha M. Linehan, professor of psychology at the University of Washington, says that while people with bipolar disorder swing between all-¬encompassing periods of mania and major depression, the mood swings typical in BPD are more specific. She says, "You have fear going up and down, sadness going up and down, anger up and down, disgust up and down, and love up and down."