Abstract
Objectives: To first explore the role of plasma vascular endothelial growth factor (VEGF) concentrations in ketamine's antianhedonic effects, focusing on Chinese patients with treatment-refractory depression (TRD). Methods: Seventy-eight patients with treatment-refractory major depressive disorder (MDD) or bipolar disorder (BD) were treated with six ketamine infusions (0.5 mg/kg). Levels of anhedonia were measured using the Montgomery-Åsberg Depression Rating Scale (MADRS) anhedonia item at baseline, day 13 and 26. Plasma VEGF concentrations were examined at the same time points as the MADRS. Results: Despite a significant reduction in anhedonia symptoms in individuals with treatment-refractory MDD (n = 59) or BD (n = 19) after they received repeated-dose ketamine infusions (p < 0.05), no significant changes in plasma VEGF concentrations were found at day 13 when compared to baseline (p > 0.05). The alteration of plasma VEGF concentrations did not differ between antianhedonic responders and non-responders at days 13 and 26 (all ps > 0.05). Additionally, no significant correlations were observed between the antianhedonic response to ketamine and plasma VEGF concentrations (all ps > 0.05). Conclusion: This preliminary study suggests that the antianhedonic effects of ketamine are not mediated by VEGF.