Serum brain-derived neurotrophic factor level is reduced in antidepressant-free patients with late-life depression

Objectives. The aim of the present study is to investigate serum BDNF levels in older depressed patients as compared to healthy elderly controls. Methods. Twenty-nine elderly subjects with major depression and 42 healthy older adults were enrolled to this study. All depressed patients were antidepressant-free for at least 1 month prior clinical and laboratorial assessments. Serum BDNF levels were determined by sandwich ELISA. Results. BDNF levels were lower in elderly depressed patients as compared to controls (P0.034). Patients with late-onset depression had the lowest BDNF level (median 478.5, interquartile range 373.5740.9 pg/l) when compared to early-onset depression (median 620.7, interquartile range 366.1971.9 pg/l) and healthy controls (median 711.3, interquartile range 534.71181.0 pg/l) (P<0.03). Conclusions. Reduced serum BDNF level may be a state marker of late-life depression in non-medicated elderly patients. Our findings provide further evidences that reduced neurotrophic support may have an important role in the physiopathology of late-life depression.