A new bipolar spectrum concept: a brief review.

Research on the broad bipolar spectrum is dependent on the definition of hypomania. We recently proposed a new, softer syndromal definition with clinical validity. This broadens the diagnosis of bipolar II (BP-II) disorder at the expense of major depressive disorder (MDD). There is evidence for a third group of suspected BP-II manifesting major depression plus hypomanic symptoms. The two bipolar-II groups together are as prevalent as MDD. A new concept of minor bipolar disorder embracing dysthymia, minor and recurrent brief depression with hypomanic syndromes and symptoms is discussed. Some methodological pitfalls of research on drug-induced hypomania as an element of the bipolar spectrum are also summarized.