No association between the response to the addition of an atypical antipsychotic drug to an selective serotonin reuptake inhibitor or serotonin norepinephrine reuptake inhibitor and the brain-derived neurotrophic factor (Val66Met) polymorphism in refractory major depressive disorder in Japanese patients

Objective: This study examined the association between the brain-derived neurotrophic factor (BDNF) (Val66Met) polymorphism and the response to the addition of an atypical antipsychotic drug to a selective serotonin reuptake inhibitor (SSRI) or serotonin-norepinephrine reuptake inhibitor (SNRI) in treatment-refractory depression. Methods: The study enrolled 64 patients meeting the Diagnostic and Statistical Manual of Mental Disorders-IV criteria for major depressive disorder who were treated with at least two courses of a single antidepressant, but who had Hamilton Depression Rating Scale (HAMD-17) scores ≥15 points that were reduced less than 50% over at least a 4-week treatment period. There were 24 males and 40 females (age range 27-68 years; mean±SD, 48±13 years). The patients' clinical improvement was evaluated using the HAMD-17. Patients with at least a 50% decrease in the HAMD-17 score were defined as responders. Serum BDNF levels were assayed using enzyme-linked immunosorbent assays and the presence of the BDNF (Val66Met) polymorphism was determined using the TaqMan genotyping assay. Results: No correlation was found between the BDNF (Val66Met) polymorphism and a positive response to adding an atypical antipsychotic drug. No differences were observed in the changes in the serum BDNF levels and HAMD-17 scores between Val66Val and Met-carriers. In addition, in patients who experienced remission, the atypical antipsychotic drug was discontinued after at least 3 months of treatment and the patients were then followed for 1 year; 14 of 27 patients (52%) relapsed within 1 year. Conclusion: These results suggest that the BDNF (Val66Met) polymorphism is not associated with the response to the augmentation of a SSRI or SNRI with an atypical antipsychotic drug, and that the combination of an atypical antipsychotic drug and a SSRI or SNRI should be continued for 3 months or more in refractory depressed patients in the Japanese population. Copyright