Impact of depressive mixed state in an emergency psychiatry setting: a marker of bipolar disorder and a possible risk factor for emergency hospitalization.

BACKGROUND: Depressive mixed state (DMX) has been reported to be one of the most useful clinical markers for bipolar II disorder (BP-II) in the outpatient setting. However, the significance of DMX in emergency psychiatry has not been well studied. METHODS: A chart review study of 139 patients who were hospitalized in an emergency psychiatric ward with an initial diagnosis of major depressive disorder (MDD). RESULTS: In 42 (30.2%) patients, the diagnosis was changed to bipolar disorder after a median observation period of 189 days from hospitalization, and of these, 34 were diagnosed as having BP-II. DMX was observed in 56 (40.3%) patients at the time of hospitalization. Compared with patients who remained in MDD, significantly more patients who later developed bipolar disorder had experienced DMX (59.5% vs. 32.0%, p = 0.0044). In multivariate analysis, DMX was one of the independent predictors of conversion to bipolar disorder (OR 2.45, p = 0.037), and the independent predictors for DMX were chronic depression and atypical features (OR 2.85, p = 0.010; OR 3.67, p = 0.046, respectively). In addition, DMX was significantly more frequently observed at emergency hospitalization than at non-emergency hospitalization (48.6% vs. 29.1%, p = 0.0065). LIMITATIONS: A single reviewer evaluated DMX by chart review. CONCLUSION: DMX is a useful marker of bipolar disorder (mainly BP-II) in the emergency psychiatric setting and is closely related to emergency hospitalization for mood disorders. To confirm these findings, a prospective study that systematically evaluates DMX is needed.

Immobilization stress-induced increment of lactate metabolism in the basolateral amygdaloid nucleus is attenuated by diazepam in the rat.

Using in vivo microdialysis technique, extracellular lactate levels were measured in the basolateral amygdaloid nucleus of the rat under immobilization stress. Immobilization stress (40 min) led to a tetrodotoxin-reversible increase in dialysate lactate levels. Diazepam (1.0 mg/kg, i.p.) reduced the ability of immobilization stress to increase lactate levels. Furthermore, the attenuation of the immobilization stress-induced increase of lactate levels by diazepam was antagonized by pretreatment with flumazenil (15 mg/kg, i.p.), a selective antagonist at benzodiazepine receptors. These findings suggest that immobilization stress increases lactate levels in rat basolateral amygdaloid nuclei, which is attenuated by stimulation of benzodiazepine receptors.