4 Variants of Bipolar Disorder Recognized in ICD and DSM

BD-I requires at least one manic episode to establish the diagnosis; depressive and hypomanic episodes are optional from a diagnostic point of view, even though clinically they are the more common presentations.

BD-II requires a history of at least one major depressive episode and one hypomanic episode; the depressive episode is far more likely to come to clinical attention.

Cyclothymic disorder requires a year or more of hypomanic/manic symptoms and depressive or dysthymic symptoms, not rising to the level of full-blown mania (otherwise the diagnosis is bipolar I) or major depression (which indicates bipolar II).

Other specified bipolar and related disorders are diagnosed by exclusion of the previous three. The diagnosis can include cases with hypomania in the absence of major depression, insufficient duration of episode, not quite enough symptoms to meet the formal definition, and brief (eg, approximately 6 months) cyclothymic presentations. Clinically, 2- or 3-day hypomanias are common, and do not appear to differ meaningfully from full-duration hypomania. Episodic presentation of symptoms is more suggestive of mood disorder than more chronic histories of the same symptoms.

For more on this topic, see Diagnostic and Treatment Challenges in Bipolar Disorder in Children and Adolescents, on which this slideshow is based.