Prediction of the Therapeutic Response in Depression Based on Neuro-computational Modeling Assessment of Motivation

Patients with major depressive disorder Inclusion Criteria: * Meeting DSM-5 criteria for major depressive disorder (single or recurrent episodes) * With a MADRS score \>= 24 * For which a new line of treatment is needed * No previous line of antidepressant for this episode or wash-out long-enough to avoid carry-over effects * Valid health care insurance Exclusion Criteria: * Treatment-resistant depression (defined as insufficient response despite at least 2 trials of antidepressant prescribed at adequate dose and duration) * Subjects with a trial of escitalopram and/or vortioxetine for the current episode, or with contra-indication to one of these two drugs * Subjects with a diagnostic of persistent depressive disorder, bipolar disorder or schizophrenia, neurodeveloppemental disorder, unremitted substance abuse disorder other than tobacco, personality disorder severe enough to compromise the follow-up (based on investigator's appreciation). * Subject with a history of neurological disorder: parkinson's disease, dementia * Contraindications to MRI scanning: pregnancy, claustrophobia, metallic implants * Pregnant or breastfeeding women * involuntary hospitalisation and legal protection measures Healthy volunteers Inclusion Criteria: \- Valid health care insurance Exclusion Criteria: * Subjects with a diagnostic of persistent depressive disorder, bipolar disorder or schizophrenia, neurodeveloppemental disorder, unremitted substance abuse disorder other than tobacco, personality disorder severe enough to compromise the follow-up (based on investigator's appreciation). * Subject with a history of neurological disorder: parkinson's disease, dementia * Contraindications to MRI scanning: pregnancy, claustrophobia, metallic implants * Pregnant or breastfeeding women