Bipolar spectrum: a review of the concept and a vision for the future

This paper reviews the bipolar spectrum concept historically and empirically. It describes how the concept derives from Kraepelin, but was lost with DSM-III, which divided the broad manic-depressive illness concept, based on recurrent mood episodes of either polarity, to the bipolar versus unipolar dichotomy, based on allowing non-recurrent mood episodes of only one polarity. This approach followed the views of Karl Leonhard and other critics of Kraepelin. Thus post DSM-III American psychiatry is not neo-Kraepelinian, as many claim, but neo-Leonhardian. The bipolar spectrum approach, as advocated by Akiskal and Koukopoulos first, harkens back to the original broad Kraepelinian view of manic-depressive illness. The evidence for and against this approach is discussed, and common misconceptions, including mistaken claims that borderline personality is similar, are revealed and critiqued.