Brain Imaging Techniques That Predict Antidepressant Responsiveness

This is a single site, controlled, double-blind study of outpatients. There are two arms: 1. Forty participants who have a current Diagnostic and Statistical Manual of Mental Disorders, 4th edition, text revised (DSM-IV-TR) diagnosis of Major Depression will be recruited. These subjects will be randomized to receive one of two antidepressant medications: Fluoxetine or Venlafaxine ER for the duration of the study. Subjects will gradually be titrated onto the medications and will be seen in the clinic up to 18 times for medication checks, to monitor side effects and depressive symptoms, including suicidal ideation. In the event of suicidal ideation, subjects will be withdrawn from the study and referred for immediate treatment. 2. Twenty normal control subjects with no current or past DSM-IV-TR diagnosis and will receive no medication. Normal control subjects will have up to 5 visits while in the study. Subjects will contact study staff to complete a phone screen and then eligible subjects will complete a clinic screen. Subjects will then be scheduled to attend the magnetic resonance imaging (MRI) simulation visit and if subjects continue to meet entrance criteria, they will be scheduled for the first MRI. Following the first MRI, subjects in the medication conditions will begin receiving medication. All subjects will undergo 3 functional magnetic resonance imaging (fMRI)s during the study: at the beginning of the study, approximately 8 weeks and 26 weeks later. During the MRI, subjects will view slides with positive and negative emotional content. Subjects will complete various clinical interviews or rating scales assessing mood and side effects at each of the visits.