While I appreciate the DSM, the diagnostic manual missed 2 categories of bipolar disorder that are particularly relevant to treatment. They are classic and atypical bipolar.
In classic bipolar disorder, hypo/manic and depressive symptoms are clearly separated, without much overlap. Affected patients are so responsive to lithium that Terrence Ketter proposed calling their disorder Cade’s disease, in homage to the Australian psychiatrist who discovered lithium.1 Other signs of classic bipolar disorder are listed in the Table. Patients need not have all these signs, but lithium is a good option if these features predominate.2
The alternative form of bipolar doesn’t have an official name, but a textbook on the subject called it atypical bipolar, after the DSM-III term for other specified bipolar.3 I’ll revive that wording here, though I also intend to clarify its definition a bit.
Atypical bipolar is marked by mixed states, rapid cycling, and a lack of full recovery between episodes. These patients are more responsive to anticonvulsants and atypical antipsychotics, but lithium should not be ruled out as it may work for them as well.4,5
The atypical and classic forms have opposite features (see Table).6,7,8 The atypical form is often missed in practice but—ironically— it is more common than the textbook case of classic bipolar. Even Emil Kraepelin, who wrote the original textbook on manic depression, noted the high frequency of these atypical forms and complained that his colleagues were more interested in “pure forms” of the illness.8
Dr. Aiken is the Director of the Mood Treatment Center, Editor in Chief of The Carlat Psychiatry Report, and Instructor in Clinical Psychiatry at the Wake Forest University School of Medicine. He has served as a subinvestigator on phase-III clinical trials and his research interests include diagnosis of mood disorders, novel pharmacologic agents, and natural and environmental approaches to mental health. He is the coauthor with Jim Phelps, MD, of Bipolar, Not So Much, a self-help book for Bipolar II (W.W. Norton & Co; 2017). He does not accept honoraria from pharmaceutical companies.
1. Ghaemi SN, Ko JY, Goodwin FK. “Cade’s disease” and beyond: misdiagnosis, antidepressant use, and a proposed definition for bipolar spectrum disorder. Can J Psychiatry. 2002;47:125–134.
2. Rybakowski JK. Factors associated with lithium efficacy in bipolar disorder. Harv Rev Psychiatry. 2014;22:353–357.
3. Marneros A, Goodwin F. Bipolar Disorders: Mixed States, Rapid Cycling and Atypical Forms. 2005. Cambridge University Press, Cambridge, UK.
4. Muneer A. Mixed states in bipolar disorder: etiology, pathogenesis and treatment. Chonnam Med J. 2017;53:1–13.
5. Grunze H, Walden J. Relevance of new and newly rediscovered anticonvulsants for atypical forms of bipolar disorder. J Affect Disord. 2002;72:S15–S21.
6. Etain B, Lajnef M, Brichant-Petitjean C, et al. Childhood trauma and mixed episodes are associated with poor response to lithium in bipolar disorders. Acta Psychiatr Scand. 2017;135:319–327.
7. Perugi G, Quaranta G, Dell'Osso L. The significance of mixed states in depression and mania. Curr Psychiatry Rep. 2014;16:486.
8. Kraepelin E. Manic-Depressive Insanity and Paranoia. 1921. Edinburgh: E&S Livingstone.
9. Tondo L, Baldessarini RJ, Hennen J, et al. Lithium maintenance treatment of depression and mania in bipolar I and bipolar II disorders. Am J Psychiatry. 1998;155:638–645.
10. Aiken CB, Weisler RH, Sachs GS. The Bipolarity Index: a clinician-rated measure of diagnostic confidence. J Affect Disord. 2015;177:59–64.