Serum brain-derived neurotrophic factor following oral esketamine in treatment-resistant depression: Results from a randomized placebo-controlled trial.
Journal of affective disorders July 16, 2026 Sara Massetti, Sanne Y Smith-Apeldoorn, Jolien K E Veraart et al.
Ketamine and its enantiomer esketamine are effective in only 30-35% of patients with treatment-resistant depression. Increased serum brain-derived neurotrophic factor (BDNF) after a single intravenous dose has been proposed as a biomarker of antidepressant response, but effects under different treatment schedules are unclear. In a randomized, placebo-controlled trial of six-week, low-dose, oral esketamine (90 mg/day, three 30 mg intakes), depression severity and serum BDNF were measured in 54 patients at baseline, end of treatment, and after a four-week washout. BDNF levels did not significantly differ between esketamine and placebo groups during treatment or washout. An increase in BDNF occurred regardless of treatment condition.