AUTHOR=Zheng Wei , Yang Xin-Hu , Gu Li-Mei , Tan Jian-Qiang , Zhou Yan-Ling , Wang Cheng-Yu , Ning Yu-Ping TITLE=A comparison of the antianhedonic effects of repeated ketamine infusions in melancholic and non-melancholic depression JOURNAL=Frontiers in Psychiatry VOLUME=Volume 13 - 2022 YEAR=2022 URL=https://www.frontiersin.org/journals/psychiatry/articles/10.3389/fpsyt.2022.1033019 DOI=10.3389/fpsyt.2022.1033019 ISSN=1664-0640 ABSTRACT=Objectives: Melancholic depression may respond differently to certain treatments. The aim of this study was to compare the antianhedonic effects of six intravenous injections of 0.5 mg/kg ketamine in patients with melancholic and nonmelancholic depression, which remain largely unknown. Methods: Individuals experiencing melancholic (n=30) and nonmelancholic (n=105) depression were recruited and assessed for anhedonic symptoms using the Montgomery–Åsberg Depression Rating Scale (MADRS). The presence of melancholic depression was measured with the depression scale items at baseline based on DSM-5 criteria. Results: A total of 30 (22.2%) patients with depression fulfilled the DSM-5 criteria for melancholic depression. Patients with melancholic depression had a nonsignificant lower antianhedonic response (43.3% versus 50.5%, t=0.5, p>0.05) and remission (20.0% versus 21.0%, t=0.01, p>0.05) to repeated-dose ketamine infusions than those with nonmelancholic depression. The melancholic group had significantly lower MADRS anhedonia subscale scores than the nonmelancholic group at day 26 (p<0.05). Conclusion: After six ketamine infusions, the improvement of anhedonic symptoms was found in both patients with melancholic and nonmelancholic depression, and the efficacy was similar in both groups.