Effects of subanesthetic repeated esketamine infusions on memory function and NGF in patients with depression: An open-label study.

In patients with depression, six intravenous infusions of esketamine (0.4 mg/kg) over 11 days significantly reduced depressive symptoms, with mean Montgomery-Asberg Depression Rating Scale scores dropping from 32.11 to 15.10. Memory function—including immediate memory, language, attention, and delayed memory—improved, and plasma nerve growth factor (NGF) levels rose from 226.13 to 384.37 pg/mL. A positive correlation existed between baseline memory function and NGF levels, while higher baseline memory was linked to smaller NGF increases. These findings suggest NGF may contribute to esketamine's memory-enhancing effects, though the open-label design limits certainty.

Study at a glance

Abstract

Subanesthetic ketamine is a rapidly acting antidepressant, yet the effects of ketamine on cognitive function are inconsistent. The primary objective of this study was to explore the effects of esketamine on memory function and plasma levels of nerve growth factor (NGF) in patients with depression. A total of 132 patients with depression completed six intravenous esketamine infusions (0.4 mg/kg) over 11 days. Depressive symptoms and neurocognitive function were assessed using the Montgomery-Asberg Depression Rating Scale (MADRS) and Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). Plasma NGF levels were assayed by enzyme-linked immunosorbent assay (ELISA). The mean MADRS score of depressed patients decreased from 32.11 ± 10.06 to 15.10 ± 8.62 after six infusions. Significant improvement in immediate memory, language, attention, and delayed memory were observed. NGF plasma levels increased from 226.13 ± 61.73 to 384.37 ± 56.89. Pearson's correlation analysis showed a positive correlation between memory function and NGF levels at baseline. The baseline memory function was negatively associated with the changes in NGF levels. The major limitation of this study is the open-label design. Subanesthetic esketamine infusions could improve depressive symptoms and neurocognitive function. Our study showed increased plasma NGF levels in depressed patients after treatment, suggesting that NGF may play a role in the improvement of memory function by esketamine.