['Remission, the primary goal of treatment for major depressive disorder (MDD), is the absence of significant signs or symptoms and the return to a state of normal functioning. A recent study found that the level of brain-derived neurotrophic factor (BDNF) increased after antidepressant treatment in remitted patients. This study evaluated serum BDNF levels in MDD patients with chronic maintenance treatment, and compared these between remission and nonremission groups.', 'Serum BDNF levels were measured in 34 MDD patients and 35 healthy controls. The severity of depression was measured using the Hamilton Depression Rating Scale (Ham-D). The MDD patients were divided into remission and nonremission groups according to a cutoff total Ham-D score of either ≤7 or ≤6.', 'Serum BDNF levels differed significantly between the remission, nonremission, and healthy control groups (P<0.05). The Bonferroni post hoc test confirmed that serum BDNF levels were significantly lower in the nonremission group than in the healthy-control group (P<0.05), but did not differ significantly between the remission and healthy-control groups.'] Are lower serum brain-derived neurotrophic factor levels associated with failure to achieve remission in patients with major depression after escitalopram treatment?