Hu X, et al. - In drug-naïve major depressive disorder (MDD) patients researchers evaluated which hippocampal subfield volumes could predict an early response to first-time use of antidepressants. Participants in this prospective study were 38 drug-naïve MDD patients and 55 healthy control subjects (HCS). Findings revealed that significantly larger volumes were seen in nonresponding patients vs both early responding patients and HCS in bilateral subiculum, cornu ammonis 1 and left CA2/3, CA4/dentate gyrus. They suggested that volumes of certain hippocampal subfields could be related to antidepressant treatment and this potentially has value for treatment selection in patients with MDD at an early stage.