Blood BDNF level is gender specific in severe depression

Abstract

Though the role of brain derived neurotrophic factor (BDNF) as a marker for major depressive disorder (MDD) and antidepressant efficacy has been widely studied, the role of BDNF in distinct groups of patients remains unclear. We evaluated the diagnostic value of BDNF as a marker of disease severity measured by HAM-D scores and antidepressants efficacy among MDD patients. Fifty-one patients who met DSM-IV criteria for MDD and were prescribed antidepressants and 38 controls participated in this study. BDNF in serum was measured at baseline, 1st, 2nd and 8th treatment weeks. Depression severity was evaluated using the Hamilton Rating Scale for Depression (HAM-D). BDNF polymorphism rs6265 (val66met) was genotyped. We found a positive correlation between blood BDNF levels and severity of depression only among untreated women with severe MDD (HAM-D>24). Serum BDNF levels were lower in untreated MDD patients compared to control group. Antidepressants increased serum BDNF levels and reduced between-group differences after two weeks of treatment. No correlations were observed between BDNF polymorphism, depression severity, duration of illness, age and BDNF serum levels. Further supporting the role of BDNF in the pathology and treatment of MDD, we suggest that it should not be used as a universal biomarker for diagnosis of MDD in the general population. However, it has diagnostic value for the assessment of disease progression and treatment efficacy in individual patients.

Fig 1. Scatter plot of the correlation between serum BDNF levels and HAM-D scores at baseline.

Data represent entire results (A), results obtained with HAM-D>24 excluding criteria (see Results section) applied to all patients (B) as well as to males (C) and females (D) separately. Statistical significance between groups for each time point was assessed using two tailed Pearson correlation analysis, indicated by p-value.

Fig 2. Serum BDNF levels of MDD patients and healthy controls.

Data represent four different time points: baseline (0) and 1^st, 2^nd and 8^th weeks of treatment respectively. Statistical significance between groups for each time point was assessed using t-test, indicated by p-value.