Association of Serum Biomarker Levels and BDNF Gene Polymorphism with Response to Selective Serotonin Reuptake Inhibitors in Indian Patients with Major Depressive Disorder.

INTRODUCTION Depression is a major public health problem. Response to selective serotonin reuptake inhibitor (SSRI) treatment varies considerably between patients. In the context of polygenic diseases like depression, measurement of a panel of biomarkers involved in the pathophysiology of depression might help predict outcome to treatment with SSRIs. OBJECTIVE The objective was to establish the relationship between serum biomarker levels and the brain-derived neurotrophic factor (BDNF) val66met polymorphism and response to SSRIs in patients with major depressive disorder. METHODS 50 patients with moderate to severe depression were recruited from the Department of Psychiatry, Sri Ra-machandra Institute of Higher Education and Research. Blood samples were collected, and Hamilton Depression Rating Scale scoring was done at baseline and after 8 weeks of treatment with SSRIs. Baseline and post-treatment levels of high-sensitivity C-reactive protein (hsCRP), BDNF and neuregulin 1β1 (NRG1β1) were analysed using commercially available ELISA kits. Genotyping of the BDNF Val66Met polymorphism was performed using a PCR-RFLP method. RESULTS Following treatment, there was a significant decrease in the mean hsCRP and NRG1β1 levels and a significant increase in the mean BDNF level. Responders had significantly lower baseline hsCRP and higher baseline BDNF levels when compared to non-responders. Response rates were significantly higher in the Val/Val group when compared to the Val/Met group. CONCLUSIONS Baseline serum levels of hsCRP and BDNF predicted response to SSRIs in major depressive disorder, and Val/Val patients responded better when compared to patients carrying the Met allele.