Abstract
Bipolar II disorder (BD II) is defined as mood disorder with recurrent episodes of depression and hypomania. BD II is officially recognized as a mental disorder in DSM-IV bud not i ICD-10.
Previous studies indicate that BD II is a relatively common disorder with a chronic recurrent course and strong predominance of depressive episodes. BD II from unipolar disorder (recurrent depressive disorder) differs by the presence of spontaneous episodes of hypomania, which are often unrecognized in clinical practice.
Other distinguishing characteristics of BD II compared with unipolar disorder are lower age of onset, more bipolar family history, higher number of depressive episodes and more atypical or mixed depressions. The impact of illness on the global functioning is in many respects comparable with bipolar I disorder.
Treatment of BD II is still poorly evidence-based.