This article is from the Bipolar Disorder FAQ, by firstname.lastname@example.org (Barry Campbell) with numerous contributions by others.
The "rapid-cycling" form of Bipolar Disorder involves four or more complete
mood cycles within a year's time, and some rapid-cyclers can complete a mood
cycle in a matter of days--or, more rarely, in hours. Studies show that women
are more likely than men to be diagnosed as rapid-cyclers.