An Association Study between Various Adrenergic Alpha 2 Receptor Polymorphisms and Treatment Response to Mirtazapine in Major Depression

ABSTRACT

OBJECTIVES: Genetic differences may contribute to the inter-individual differences in treatment response to antidepressants among patients suffering from major depression. This study investigated a possible association of treatment response to mirtazapine with various adrenergic alpha 2 receptor polymorphisms in major depressive patients. METHODS: A 6-week naturalistic treatment study with a blinded outcome examined 84 Korean patients with major depression. Treatment response to mirtazapine was defined as > or =50% decrease in HAM-D scores at six weeks. In this study, four genetic polymorphisms were selected ; ADRA2A MspI, ADRA2A DraI, alpha2BDel301-303, and alpha2CDel322-325. RESULTS: The Del/Del genotype of alpha2CDel322-325 exhibited a significant association with response to mirtazapine through multiple logistic regression. ADRA2A DraI, alpha2BDel301-303, and alpha2CDel322-325 did not showed a significant association with response to mirtazapine. CONCLUSION: Based on the finding that alpha2CDel322-325 polymorphism had an association with the mirtazapine response, we postulate that the polymorphism related to the mechanism of the antidepressant effect is important in predicting the response to antidepressants.