Association study of serotonin 1B receptor (A-161T) genetic polymorphism and suicidal behaviors and response to fluoxetine in major depressive disorder

Serotonin 1B receptors (5-HT1B) are autoreceptors involved in the local inhibitory control of serotonin release, and have been suggested to play a role in the pathogenesis of major depressive disorder (MDD) and the antidepressant effects of the selective serotonin reuptake inhibitors in patients. We genotyped the 5-HT1B A-161T polymorphism in 160 patients with MDD and 160 normal controls. We then tested the hypothesis that the allelic variant, A-161T, of the 5-HT1B gene confers susceptibility to MDD or is associated with suicide attempt. We also examined the association of this polymorphism with therapeutic response in 116 of the MDD patients who received fluoxetine treatment for 4 weeks. No significant difference was found in the A-161T genetic polymorphism between MDD patients and controls. The genotype distribution between patients with and without suicide attempt, or between fluoxetine treatment responders and nonresponders were also similar. Our findings suggest that 5-HT1B A-161T genetic polymorphism does not play a major role in the susceptibility to MDD, nor is it related to suicidal attempt or the therapeutic response to fluoxetine in MDD.