What do you think is the difference? A lot of people use the timing of the mood fluctuations to differentiate between the two, but many of us suffer from ultra-rapid cycling. Triggered vs. non-triggered mood switches are also used, but many people with bp said that they have a lot of triggered mood changes in this thread: http://forums.psychcentral.com/showthread.php?t=200020

Relationship and attachment issues are thought to be more of a bpd issue, but it is easy to see how the mood cycling in bipolar could easily make relationships more difficult, and it indeed it often does.

The borderline forum hosted this excellent discussion on this topic: http://forums.psychcentral.com/showthread.php?t=200468

I think it is time that we with bipolar consider this issue. Where do you draw the line between the two conditions?

Sometimes I think that there is no substantial difference. Other times I feel that the differing prognoses (bpd tends to improve with time, bipolar unfortunately follows the opposite trend) suggest that there must be a real, underlying biological difference.