Intestinal Flora and Major Depressive Disorders

Participants (30 patients and 10 controls) will be recruited in the clinical psychological department of Beijing Chaoyang hospital. Patients with first-episode major depressive disorder confirmed by structured diagnostic interview (Chinese mini version) and assessment of symptom severity (Hamilton Depression Scale-17, HAMD-17) will be enrolled in a six-month open study. Healthy controls matched for age, sex and body-mass index (BMI) will have only baseline stool and electroencephalography (EEG) collections. We then will make an assessment of HAMD-17, patient-reported outcomes, and EEGs identified at the pre-treatment and those same parameters at the 1- to 6-month point. Treatment response (50% reduction in HAMD-17), treatment remission (HAMD-17\<7, at least 3 weeks) will be analyzed with change in microbiome, inflammation markers and EEG. We will analyze the differences in the intestinal flora community structure and diversity of patients and controls in order to obtain information on key different bacteria. We will conduct the correlation between each genus of bacteria in the intestinal flora and the total score of HAMD-17 in order to reveal the dynamic succession change of the intestinal flora with the disease state of major depressive disorder. The analysis with multiple testing corrections will be analyzed between depressive severity, EEG and gut microbiome composition. The results of this study will provide the objective and direct biomarkers for major depressive disorder to achieve remission. This study will bring an important scientific basis to further optimizing treatment methods and improvie clinical effect.