Depressive mixed state: Evidence for a new form of depressive state in type I and II bipolar patients

BACKGROUND: A high proportion of unipolar and bipolar type II patients can present a depressive mixed state (DMX). This state is defined by an association of a major depressive episode with at least two specific hypomanic symptoms. This state seems underdiagnosed and this could have treatment implications. The aims of our study were: (i) to investigate the frequency of DMX in type I and II bipolar patients hospitalized for a severe or resistant depressive episode and (ii) to assess the therapeutic response in naturalistic conditions. METHODS: Forty-two consecutive bipolar patients referred by psychiatrists for a severe or resistant depressive episode were assessed using the French version of the Mini International Neuropsychiatric Interview 5.0 (MINI 5.0), which assesses the suicide risk and provides DSM-IV diagnosis. The intensity of mood episodes was evaluated using the MADRS and Bech-Rafaelsen Mania Scale. One group of patients included patients presenting only depressive symptoms (ie, pure major depressive episode (MDE)), and the second group included patients with a major depressive episode and at least two specific hypomanic symptoms (DMX). RESULTS: Twenty-one patients (50%) had a pure MDE and 21 patients (50%) had a DMX. The treatment leading to recovery was very different in the two groups. Antidepressants were effective (77%) in MDE patients, whereas antipsychotics were effective (81%) in DMX. 38% of patients with a MDE also received a mood stabilizer versus 86% in the group of DMX. Five MDE patients (24%) and one DMX patient required electroconvulsive therapy. The suicidal ideations did not differ between the two groups (p = 0.7). CONCLUSIONS: Some mood episodes in bipolar patients (type I and II) are characterised by depressive and hypomanic symptoms but do not meet criteria for mixed episode as defined by DSM-IV. These episodes are often diagnosed as depressive states, but are worsened by antidepressants and often considered as resistant depression. They rapidly respond to antimanic treatment. New categories of mood disorders should take into account this particular mixed state.