The BDNF Val66Met polymorphism is associated with escitalopram response in depressed patients

The brain-derived neurotrophic factor (BDNF) gene is a candidate gene in therapeutic responses to antidepressants. The aim of the study was to determine the effects of BDNF allelic variability on responses to escitalopram treatment at 3 weeks after treatment initiation and at a 6-week endpoint. We included 187 Caucasian subjects with depression; 153 completed the 6-week study. Clinical evaluation was performed using the Montgomery and Asberg Depression Rating Scale (MADRS) before and after 3-6 weeks of treatment. After 3 weeks of treatment, we saw significantly better treatment responses in the Met carriers and greater antidepressant resistance among the Val/Val homozygotes. Relative to Val/Val homozygous (59.78 %), a significantly greater proportion of subjects Met-carriers (77.94 %) responded to escitalopram treatment (chi (2) = 5.88, p = 0.015). After 6 weeks, we found the same pattern of results but this effect did not reach statistical significance (chi (2) = 2.07, p = 0.15). These findings highlight a significant association between the BDNF valine to methionine substitution (Val(66)Met) polymorphism and the treatment response to escitalopram in a Caucasian population of severely depressed inpatients.