Which could be a clinically useful definition of depressive mixed state?

Depressive mixed state (DMX) (major depressive episode [MDE] with few superimposed hypomanic symptoms) was reported to be common among depressed outpatients. Study aim was to find if the best clinically useful definition of DMX was one based on a minimum number of hypomanic symptoms, or instead one based on the combination of specific hypomanic symptoms. Methods: Consecutive 138 bipolar II and 83 unipolar MDE outpatients were interviewed with DSM-IV Structured Clinical Interview. DMX definitions tested were: MDE with three or more hypomanic symptoms (DMX3) and MDE with hypomanic symptoms irritability, distractibility and racing thoughts. Results: DMX3, and the combination of racing thoughts, irritability and distractibility, had the same significant and nonsignificant associations with study variables. DMX3, and the combination of the specific hypomanic symptoms, significantly predicted bipolar II diagnosis. For predicting bipolar II diagnosis. DMX3 had higher specificity (86.7% vs. 50.6%), while the combination of the specific hypomanic symptoms had higher sensitivity (76.8% vs. 51.4%). Conclusions: A DMX definition with higher specificity (DMX3) for predicting bipolar II diagnosis may, be more clinically useful because it may reduce misdiagnosis. (C) 2002 Elsevier Science Inc. All rights reserved.