Hippocampal volume as treatment predictor in antidepressant naïve patients with major depressive disorder

Major depression disorder (MDD) limits psychosocial functioning and quality of life. One of the biological alterations is a hippocampal volume (HV) reduction. Previous prospective neuroimaging studies present inconsistencies regarding HV reductions and clinical features and response of antidepressant treatment of the participants. To clarify the relationship between antidepressant response and the HV reported, we prospectively evaluated antidepressant-naïve subjects diagnosed with MDD for the first time. We recruited twenty-one subjects and applied the Hamilton Depression Rating Scale (HAM-D), Montgomery-Asberg Depression Rating Scale (MADRS), Beck Depression Inventory (BDI), and the Clinical Global Impression (CGI) scale. The participants underwent brain Magnetic Resonance Imaging (MRI) scanning to measure the HV, and subsequently were treated naturalistically with first-line antidepressant medication for eight weeks. Thirteen subjects met the criteria for remission at eight weeks of treatment. The baseline right and left hippocampal volumes were larger in subjects who achieved remission (p = 0.012) and (p = 0.001), respectively. The main finding of this study is that the antidepressant naïve subjects who met the criteria for clinical remission according to the HAM-D, MADRS, and the CGI scale scores, had larger pretreatment hippocampal volumes. Our results assess the HV as a treatment outcome predictor.