Diagnostic accuracy of serum brain derived neurotrophic factor concentration in antidepressant naïve patients with first major depression episode.

Diagnosing major depressive disorder (MDD) continues to be based on meeting phenomenological and descriptive criteria. As of yet, there is still no non-invasive, peripheral biomarker that would allow for a certain diagnosis of MDD. The objective of this paper is to use the receiver operating characteristic (ROC) analysis to test the diagnostic value of serum concentrations of brain derived neurotrophic factor (BDNF) in diagnosing the first episode of MDD. Among 1014 patients admitted for an initial psychiatric evaluation, antidepressant naïve patients diagnosed with first episode MDD were separated into the test group. Only patients signing an informed consent form were included in the study. Using DSM-IV-TR diagnostic criteria, those patients meeting the MDD criteria (N = 122) and patients not meeting MDD or other psychiatric disorder criteria (N = 142) were differentiated. Subjects with repeated episode MDD (N = 121) and other psychiatric comorbid illnesses (N = 138) in the MDD group were excluded from the study. In the group without MDD or other psychiatric illnesses, patients with physical comorbidities (N = 59) were excluded. The serum concentration of BDNF was determined in all patients using the ELISA assay. Subjects with first episode MDD showed differences in serum BDNF concentrations (ng/mL) in comparison to the control group of patients not meeting the criteria for first episode MDD (mean ± SD; 37.5 ± 13.3 vs. 56.8 ± 6.3; t = 1.372; df = 262; p < 0.01). The ROC analysis established a discriminant diagnostic value of serum BDNF in diagnosing MDD. The area under the curve (AUC) was 0.892 with a 95% confidence level (0.826-0.939), which was statistically significant at p < 0.01. The serum BDNF had a high diagnostic sensitivity of 83.9% and a specificity of 93%. Serum BDNF concentrations appear to be a promising tool in discriminating subjects with MDD from those without MDD.