Skip to main content
  • Oral presentation
  • Open access
  • Published:

Bipolar I - Biploar II distinction

Previous studies, performed in the second half of the last centruy, focused primarily on the two extreme manifestations of major mood disorders (i.e., unipolar major depression and “classical” Bipolar I disorder), and found marked differences in almost all clinical features and diagnostic validators, virtually supporting the strict categorical distinction between unipolar major depressive disorder and bipolar disorder. However, a number of recent studies clearly support the original “unitary” concept of Emil Kraepelin on the continuity between unipolar depression and (bipolar) manic-depressive illness. Nowdays it is well accepted that Bipolar I (depression with a history of mania) and Bipolar II (depression with a history of hypomania but not with mania) disorders represent two prominent clinical phenotypes at the “bipolar edge” of the full unipolar-bipolar spectrum with several similarities and differences. Phenomenologically, Bipolar II disorder is more close to Bipolar I disorder than to unipolar depression.

The clinically most important differences between Bipolar I and Bipolar II disorders are: 1/ Epidemiology, including gender ratio and age of onset, 2/ Genetical (biological) background, 3/Cross-sectional clinical picture of depression, including mixed depression/agitation and psychotic features, 4/ Psychiatric and medical comorbidity, 5/Long-term course and outcome, including rapid cycling and seasonality, 6/ Suicidal behaviour, including both attempted and comleted suicide, 7/ Affective temperament, and 8/ Artistic creativity/criminality.

Author information

Authors and Affiliations


Rights and permissions

Open Access This article is published under license to BioMed Central Ltd. This is an Open Access article is distributed under the terms of the Creative Commons Attribution 2.0 International License (, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Reprints and permissions

About this article

Cite this article

Rihmer, Z., Gonda, X. Bipolar I - Biploar II distinction. Ann Gen Psychiatry 7 (Suppl 1), S80 (2008).

Download citation

  • Published:

  • DOI: