Major depressive episodes with hypomanic symptoms are common among depressed outpatients.

Depressive mixed states (major depressive episodes [MDE] with some hypomanic symptoms) are not classified in DSM-IV. The aim of the present study was to determine the prevalence of depressive mixed states in depressed outpatients, and to compare bipolar II with unipolar depressive mixed states. Seventy consecutive bipolar II and unipolar depressed outpatients were interviewed using the DSM-IV Structured Clinical Interview (SCID). At least one hypomanic symptom was present in 90% of patients, and three or more in 28.5%. Symptoms of depressive mixed states included irritable mood, distractibility, racing thoughts, and increased talking. Bipolar II subjects had more concurrent hypomanic symptoms (three or more in 48.7% v 3.2%, P = 0.000). Depressive mixed states with three or more hypomanic symptoms correctly classified 70.0% of bipolar II subjects. These findings have important treatment implications, as antidepressants may worsen the symptoms of depressive mixed states, and mood stabilizers can be useful.