Emerging Concepts of Bipolar Disorder: Focus on Mixed States

Chung, Young In

Abstract

An admixture of affective symptoms of opposite polarity in bipolar disorders has very important clinical implications just beyond the diagnostic classification of diseases. In this respect, there are several clinical problems with the very strict concepts of bipolar mixed state according to the DSM-IV and ICD-10. First, many cases in which affective symptoms of opposite polarity are combined without fully satisfying the criteria for one or the other type of episode have been seen in clinical situations. Second, mixed symptomatology of opposite polarity frequently represents the first expression of a bipolar disorder. Third, unipolar depressives with intra-episodic expansive symptoms may not adequately respond to antidepressant drugs, which can be causative in treatment resistance or lead to cycling. Mixed state does not represent a mere combination of depressive and manic symptomatology, but a complex process of temperamental disposition and affective process. Trait factors such as hyperthymic and depressive temperaments, when opposite to the polarity of superimposed affective episodes, might underlie the affective instability of bipolar mixed states. Affective instability appears to be the clinical expression of the neurophysiological dysregulation believed to underlie bipolar disorders. Mixed state might be considered the most eloquent expression of this dysregulation. In conclusion, the concepts of bipolar mixed state will be needed to be broader than what is included in DSM-IV and ICD-10.