Decreased Levels of Serum Brain-Derived Neurotrophic Factor in Male Pediatric Patients with Depression

Background: Brain-derived neurotrophic factor (BDNF) plays an important role in the pathophysiology of ma- jor depressive disorder (MDD). Several meta-analyses have shown decreased serum levels of BDNF in adult patients with MDD, but there has been no report on the serum levels of BDNF in pediatric patients with depression. In this study, we investigated whether serum levels of BDNF are altered in pediatric patients with depression. Methods: We measured serum BDNF levels in the following four groups: male pediatric patients with depression (n = 13), female pediatric patients with depression (n = 17), and age-matched normal control subjects (n = 10 for Male, n=12 for Female). Patients were evaluated using the Children's Depression Rating Scale Revised (CDRS-R). Serum levels of BDNF were measured with the sandwich ELISA method. Results: Serum levels (6.97 ± 3.69 ng/mL (mean ± SD)) of BDNF in male pediatric patients with depression were signifi- cantly (p=0.019) lower than those (10.67 ± 3.11 ng/mL) in the male control group. However, there was no difference be- tween the female pediatric patients with depression (9.29 ± 4.61 ng/mL) and the female control group (10.21 ± 4.79 ng/mL). Furthermore, there was no correlation between serum levels of BDNF and CDRS-R scores in the pediatric pa- tients with depression. Interestingly, there was a significant negative correlation (r = -0.683, p=0.010) between the serum BDNF levels and the duration of illness in male, but not female, pediatric patients with depression. Conclusions: This study suggests that low BDNF levels may play a role in the pathophysiology of male pediatric patients with depression.