 Main objective : Using machine learning method to examine the predictive value sensitivity, specificity, accuracy of resting state and emotional task-related fMRI data collected at the pretreatment time week 0 and at the early phase of antidepressant treatment week 2 in the classification of remitters and non-remitters in patients with MDD after 12 weeks of treatment. Secondary objective: To compare the predictive value of pretreatment baseline brain activity week 0 with early treatment brain activity week 2. 