Study hypothesis: psychotherapy and SSRI treatment effect in different brain way: psychotherapy in "up to down" way and SSRI in "down to up" way. The investigators will explore this hypothesis in major depressive disorder outpatients with Magnetic Resonance Imaging analysis in this study. Patients in different groups will be treated by psychotherapy or SSRI treatment. They will all be checked with Magnetic Resonance Imaging pro and after 12 weeks of treatment.

Patients meeting the inclusion criteria undergo an examination that included a diagnostic interview, vision test, and psychophysiological measures. Participants then undergo the baseline fMRI scan within 48 hours, after that, they will receive psychotherapy or SSRI treatment.and returned the scan once they completed the therapy.

Inclusion Criteria:

• meet SCID -Ⅰ/P major depressive disorder diagnosis;
• Right handedness;
• good visual acuity.

Exclusion Criteria:

• neurological disease ;
• serious physical illness (e.g. heart, lung, liver, kidney or blood system disease);
• with other mental disorder;
• psychotic symptoms
• personality disorders;
• pregnancy;
• suicidal risk;
• treatment by antidepressants or other psychotropic medications within 6 months prior to the start of the trial;
• with contraindication for MRI