Unipolar mania: a distinct entity?

Background: Whether or not unipolar mania is a separate nosological entity remains a subject of dispute. This review discusses that question in light of recent data.

Methods: Unipolar mania studies in the PUBMED database and relevant publications and cross-references were searched.

Results: There seems to be a bipolar subgroup with a stable, unipolar recurrent manic course, and that 15-20% of bipolar patients may be unipolar manic. Unipolar mania may be more common in females. It seems to have a slightly earlier age of illness onset, more grandiosity, psychotic symptoms, hyperthymic temperament, but less rapid-cycling, suicidality and comorbid anxiety disorders. It seems to have a better course of illness with better social and professional adjustment. However, its response to lithium prophylaxis seems to be worse, although its response to valproate is the same when compared to that of classical bipolar.

Limitations: The few studies on the subject are mainly retrospective, and the primary methodological criticism is the uncertainty of the diagnostic criteria for unipolar mania.

Conclusions: The results indicate that unipolar mania displays some different clinical characteristics from those of classical bipolar disorder. However, whether or not it is a separate nosological entity has not been determined due to the insufficiency of relevant data. Further studies with standardized diagnostic criteria are needed. Considering unipolar mania as a course specifier of bipolar disorder could be an important step in this respect.