This is a broad diagnostic term that speaks to just how variable severe mood symptoms can appear.
In this category, we’ll find people who rapidly cycle through severe mood states that will meet criteria for mania or mixed or depressed states, but whose episodes don’t have the duration necessary for classification as one of the other variants.
This is also the diagnosis that would be used with someone who has recurrent bouts of hypomania without depressive episodes.
Or this could be the best-fit diagnosis for someone who has had hypomanic and some depressed episodes, but not severe enough to meet criteria for a major depressive episode or with the frequency needed for a cyclothymia diagnosis.
Right now, this diagnosis speaks to all that is not yet known about the bipolar spectrum. It’s often a useful diagnosis in the early stages of working with someone, in which not enough of the history is known, or where coexisting conditions (such as anxiety, personality traits, or substance abuse/dependence) cloud the overall picture.