Cortical activation for adolescent-onset minor depression and major depressive disorder: an fNIRS study.

BACKGROUND: While depression is increasing worldwide, some patients are diagnosed as having Major Depressive Disorder (MDD), but others are diagnosed with minor depression, however, the potential neuro mechanism is unknown. METHODS: Sixty-two patients with minor depression, 44 adolescents with MDD and 54 healthy adolescents participated in this study. Functional near-infrared spectroscopy (fNIRS), both HAMD and HAMA data were collected from all of the participants. RESULTS: The result indicates the pervasively decreased activation of BA, 11, 21, 45 and 46 were observed in the MDD group and reduced activation of BA 45 was observed in the minor depression group. However, cortical activation was not observed between the minor depression or MDD groups. Cortical activation was also not correlated with the depressive/anxious score in the minor and MDD groups separately. CONCLUSIONS: Cortical activation was pervasively decreased in the MDD group and slightly reduced in the minor depression group, which may be a potential neural mechanism. As reduced cortical activation in minor depression, interventions in the early stages of minor depression may help slow or even modify the development of the illness.

Characteristics of gut microbiota and its correlation with hs-CRP and somatic symptoms in first-episode treatment-naive major depressive disorder.

OBJECTIVE: Most patients with major depressive disorder (MDD) have somatic symptoms, but little studies pay attention in the microbial-inflammatory mechanisms of these somatic symptoms. Our study aimed to investigate alterations in gut microbiota and its correlation with inflammatory marker levels and somatic symptoms in first-episode treatment-naive MDD. METHODS: Subjects contained 160 MDD patients and 101 healthy controls (HCs). MDD patients were divided into MDD with somatic symptoms group (MDDS) and MDD without somatic symptoms group (MDDN) based on Somatic Self-rating Scale (SSS). 16S ribosomal RNA sequencing were performed to analyze the composition of the fecal microbiota. The inflammatory factors were measured using enzyme linked immunosorbent assay (ELISA). Correlation among the altered gut microbiota, inflammatory factor and severity of clinical symptoms were analysized. RESULTS: Relative to HCs, MDD patients had higher levels of high-sensitivity C-reactive protein (hs-CRP) as well as disordered α-diversity and ß-diversity of gut microbiota. Linear discriminant effect size (LEfSe) analysis showed that MDD patients had higher proportions of Bifidobacterium, Blautia, Haemophilus and lower proportions of Bacteroides, Faecalibacterium, Roseburia, Dialister, Sutterella, Parabacteroides, Bordetella, and Phascolarctobacterium from the genus aspect. Furthermore, correlation analysis showed Bacteroides and Roseburia had negative correlations with the hs-CRP, HAMD-24, the total and factor scores of SSS in all participants. Further, compared with MDDN, the Pielous evenness was higher in MDDS. Random Forest (RF) analysis showed 20 most important genera discriminating MDD-S and MDDN, HCs. The ROC analysis showed that the AUC was 0.90 and 0.81 combining these genera respectively. CONCLUSION: Our study manifested MDD patients showed disordered gut microbiota and elevated hs-CRP levels, and altered gut microbiota was closely associated with hs-CRP, depressive symptoms, and somatic symptoms.

Immunoregulatory role of the gut microbiota in inflammatory depression.

Inflammatory depression is a treatment-resistant subtype of depression. A causal role of the gut microbiota as a source of low-grade inflammation remains unclear. Here, as part of an observational trial, we first analyze the gut microbiota composition in the stool, inflammatory factors and short-chain fatty acids (SCFAs) in plasma, and inflammatory and permeability markers in the intestinal mucosa of patients with inflammatory depression (ChiCTR1900025175). Gut microbiota of patients with inflammatory depression exhibits higher Bacteroides and lower Clostridium, with an increase in SCFA-producing species with abnormal butanoate metabolism. We then perform fecal microbiota transplantation (FMT) and probiotic supplementation in animal experiments to determine the causal role of the gut microbiota in inflammatory depression. After FMT, the gut microbiota of the inflammatory depression group shows increased peripheral and central inflammatory factors and intestinal mucosal permeability in recipient mice with depressive and anxiety-like behaviors. Clostridium butyricum administration normalizes the gut microbiota, decreases inflammatory factors, and displays antidepressant-like effects in a mouse model of inflammatory depression. These findings suggest that inflammatory processes derived from the gut microbiota can be involved in neuroinflammation of inflammatory depression.

Latent classes of symptom trajectories among major depressive disorder patients in China.

OBJECTIVE: This study aimed to understand the long-term symptom trajectories of Chinese patients with major depressive disorder (MDD) using piecewise latent growth modeling and growth mixture modeling. The investigation also aimed to identify the baseline characteristics indicative of poorer treatment outcomes. METHODS: A total of 558 outpatients with MDD were assessed using a sequence of surveys. The Hamilton Rating Scale for Depression (HRSD), Hamilton Anxiety Rating Scale (HAMA), and Measurement and Treatment Research to Improve Cognition in Schizophrenia (MATRICS) Consensus Cognitive Battery (MCCB) were used to evaluate baseline depression, anxiety, and cognitive function. Depression symptom severity was subsequently measured at the 1-month, 2-month, 6-month, 1-year, and 2-year follow-ups. RESULTS: Results indicated three depressive symptomology trajectories, including (a) severe, improving class (12.72 %), (b) partially responding, later deteriorating class (6.09 %), and (c) moderate, improving class (81.18 %). Logistic regression analyses showed that a history of cardiovascular disease (CVD) increased the odds of belonging to the partially responding, later deteriorating class, whereas higher baseline depression increased the odds of belonging to the severe, improving class compared to the moderate, improving class. Patients who experienced less depression relief during the first month of treatment had a lower probability of belonging to the moderate, improving class. LIMITATIONS: Participant attrition in this study may have inflated the estimated rate of treatment-resistant patients. CONCLUSIONS: The burden of CVD and poorer initial treatment response are plausible risk factors for poorer treatment outcomes, highlighting targets for intervention in Chinese MDD patients.

The DIRECT consortium and the REST-meta-MDD project: towards neuroimaging biomarkers of major depressive disorder.

Despite a growing neuroimaging literature on the pathophysiology of major depressive disorder (MDD), reproducible findings are lacking, probably reflecting mostly small sample sizes and heterogeneity in analytic approaches. To address these issues, the Depression Imaging REsearch ConsorTium (DIRECT) was launched. The REST-meta-MDD project, pooling 2428 functional brain images processed with a standardized pipeline across all participating sites, has been the first effort from DIRECT. In this review, we present an overview of the motivations, rationale, and principal findings of the studies so far from the REST-meta-MDD project. Findings from the first round of analyses of the pooled repository have included alterations in functional connectivity within the default mode network, in whole-brain topological properties, in dynamic features, and in functional lateralization. These well-powered exploratory observations have also provided the basis for future longitudinal hypothesis-driven research. Following these fruitful explorations, DIRECT has proceeded to its second stage of data sharing that seeks to examine ethnicity in brain alterations in MDD by extending the exclusive Chinese original sample to other ethnic groups through international collaborations. A state-of-the-art, surface-based preprocessing pipeline has also been introduced to improve sensitivity. Functional images from patients with bipolar disorder and schizophrenia will be included to identify shared and unique abnormalities across diagnosis boundaries. In addition, large-scale longitudinal studies targeting brain network alterations following antidepressant treatment, aggregation of diffusion tensor images, and the development of functional magnetic resonance imaging-guided neuromodulation approaches are underway. Through these endeavours, we hope to accelerate the translation of functional neuroimaging findings to clinical use, such as evaluating longitudinal effects of antidepressant medications and developing individualized neuromodulation targets, while building an open repository for the scientific community.