CLASSIFICATION OF BIPOLAR DISORDER

This classification, summarised by Young and Klerman (1992) has been commonly used in descriptive work and in identifying groups of subjects in the bipolar spectrum. Bipolar I is the condition that has the best long-term diagnostic validity and stability and has been most researched in terms of phenomenology, course and outcome with and without treatment. Bipolar II is being increasingly recognised to be commoner than previously thought, particularly in young people, and should be screened for in every patient who presents with depression. There is growing evidence to suggest that Bipolar II responds to mood stabilizers like Bipolar I. Cyclothymia can be present over a lifetime without the development of a full-blown Bipolar Disorder. Some workers treat Cyclothymia as they would a rapid-cycling bipolar disorder. There is no consensus on whether antidepressant induced hypomania is purely an adverse effect of medication or the unmasking of a true underlying vulnerability for bipolar disorder. Recurrent major depression without hypomania or mania and with a significant family history of bipolar Disorder is a well recognised condition. A significant proportion of patients with bipolar disorder may begin their lifetime of mood problems with depression. This is particularly so in juvenile onset bipolar disorder. Unipolar Mania is a relatively uncommon yet recognised entity, and if it appears for the first time after the age of 40, should be screened for medical or neurological etiology.

References
Young RC, Klerman GL. Mania in late life: focus on age at onset. Am J Psychiatry 1992: 149: 867-876.