Wang C, Zhou Y, Zheng W, et al. - In this exploratory study, researchers ascertained if melancholic/anxious subtypes were correlated with different antidepressant outcomes of repeated-dose intravenous ketamine. The study sample consisted of 97 candidates with depression who were administered six repeated-dose intravenous ketamine and evaluated for depression (Montgomery–Åsberg Depression Rating Scale, MADRS), anxiety (Hamilton Anxiety Rating Scale, HAMA), and suicidal ideation (Beck Scale for Suicidal Ideation, SSI) at baseline, 24 h after each infusion, and 2 weeks after the whole treatment. Investigators found that patients with melancholic or melancholic–anxious characteristics were less likely to respond or remit than those with anxious or no subtype characteristics and took longer to achieve response/remission. Faster reductions in HAMA score were observed in patients with anxious or melancholic–anxious characteristics, and faster reductions in SSI score among those with melancholic-anxious characteristics were observed. The study shows positive results preferentially for treating non-melancholic or anxious depression with ketamine as a novel antidepressant.