A prospective study of inter-episode consistency of manic and mixed subtypes of bipolar disorder

Background: Few studies have compared symptom presentations across manic or mixed episodes in manic-depressive patients. Methods: In the current study we report on symptom presentations of 68 prospectively-evaluated subjects diagnosed with Bipolar Disorder during two discrete manic or mixed episodes. Each episode was categorized using DSM-IIIR criteria for Bipolar Disorder, manic or mixed, as well as a less restrictive definition for manic and mixed states derived from receiver operating characteristic (ROC) analysis of symptoms. Results: The occurrence of mixed bipolar episodes was not random using either the DSM-IIIR or ROC-derived definitions of mixed episodes. Limitations: Subjects were not all fully medication-free at the time of evaluation which may have altered symptom presentation. The total duration of the study was limited, with the longest inter-episode interval under 6 years. Conclusions: Although there was variability in mixed symptomatology between episodes, the occurrence of mixed episodes was not random. Manic and mixed episodes tend to recur true to type. (C) 2001 Elsevier Science B.V. All rights reserved.