Neuroimaging and Electrophysiology Studies in Major Depressive Disorder

INTRODUCTION The search for specific neuroimaging and electrophysiology abnormalities in major depressive disorder (MDD) is driven by a clear unmet clinical need. While first-line antidepressant treatments have response rates (defined as 50% improvement of symptoms) of 50% or more, large numbers of patients still fail to respond tomultiple interventions (1). In real-life patients (with comorbidmedical and psychiatric illnesses), the rates of remission (defined as resolution of symptoms) tend to be low (25-35%); remission rates become very low (10-20%) for those not improving after two initial treatments (2). Moreover, it takes 6 to 12 weeks to fully evaluate the efficacy of an antidepressant treatment. As each new pharmacotherapy is tried, patients are exposed to additional cost, side effect burden, and the potential for loss of function and suicide.