This is a helpful, careful discussion about treatment of bipolar depression (especially pharmacological treatment). Well worth following the URL to access the freely viewable full text - http://tinyurl.com/3kbky5

This 17 year follow-up study of 223 sufferers from bipolar I and bipolar II disorders found that still having residual symptoms after recovery more than tripled the speed of recurrence/relapse. The only other significant increased risk found was for those who had already had three or more major affective episodes.

Supports the validity of the bipolar II diagnosis, although argues that the boundaries of this disorder currently lack clarity.