A comparative study of prevalence of mixed features in patients with unipolar and bipolar depression

Identifying the DSM-5 mixed features specifier in depressed patients: A comparison of measures

BACKGROUND

A commonly used measure to assess mixed features in depressed patients is the Young Mania Rating Scale (YMRS), which only partially aligns with the DSM-5 criteria. Different algorithms on the YMRS have been used to approximate the DSM-5 mixed features criteria. In the present report from the Rhode Island Methods to Improve Diagnostic Assessment and Services (MIDAS) project, we examined the agreement and validity of different approaches towards assessing the mixed features specifier.

METHODS

Three hundred nine depressed psychiatric patients were interviewed with the Structured Clinical Interview for DSM-IV, the DSM-5 Mixed Features Specifier Interview (DMSI) and the YMRS. Seven definitions of mixed features were examined, two based on the DMSI and five from the YMRS.

RESULTS

The prevalence of mixed features varied 8-fold amongst the 7 definitions. The level of agreement between the YMRS definitions and the DMSI was poor. For each definition, mixed features were significantly more common in patients with bipolar disorder than major depressive disorder. A family history of bipolar disorder was significantly associated with the DMSI assessment of mixed features but none of the YMRS approaches.

LIMITATIONS

The ratings on the measures were not independent of each other. The sample size was too small to compare the patients with bipolar I and bipolar II disorder.

CONCLUSIONS

While there was evidence of validity for both the DSM-5 and YMRS approaches towards identifying mixed features, the 2 approaches are not interchangeable. The algorithm on the YMRS used to classify patients has a significant impact on prevalence.

Tryptophan metabolism as bridge between gut microbiota and brain in chronic social defeat stress-induced depression mice

Backgrounds

Gut microbiota plays a critical role in the onset and development of depression, but the underlying molecular mechanisms are unclear. This study was conducted to explore the relationships between gut microbiota and host's metabolism in depression.

Methods

Chronic social defeat stress (CSDS) model of depression was established using C57BL/6 male mice. Fecal samples were collected from CSDS group and control group to measure gut microbiota and microbial metabolites. Meanwhile, tryptophan metabolism-related metabolites in hippocampus were also analyzed.

Results

CSDS successfully induced depressive-like behaviors in CSDS group. The 24 differential bacterial taxa between the two groups were identified, and 14 (60.87%) differential bacterial taxa belonged to phylum Firmicutes. Functional analysis showed that tryptophan metabolism was significantly affected in CSDS mice. Meanwhile, 120 differential microbial metabolites were identified, and two key tryptophan metabolism-related metabolites (tryptophan and 5-hydroxytryptophan (5-HTP)) were significantly decreased in feces of CSDS mice. The correlation analysis found the significant relationships between tryptophan and differential bacterial taxa under Firmicutes, especially genus Lactobacillus (r=0.801, p=0.0002). In addition, the significantly decreased 5-hydroxytryptamine (5-HT) in hippocampus of depressed mice was also observed.

Conclusions

Our results showed that tryptophan metabolism might have an important role in the crosstalk between gut microbioa and brain in depression, and phylum Firmicutes, especially genus Lactobacillus, might be involved in the onset of depression through regulating tryptophan metabolism.