Association of Mu-Opioid Receptor Variants and Response to Citalopram Treatment in Major Depressive Disorder

ObjectiveBecause previous preclinical and clinical studies have implicated the endogenous opioid system in major depression and in the neurochemical action of antidepressants, the authors examined how DNA variation in the μ-opioid receptor gene may influence population variation in response to citalopram treatment. MethodA total of 1,953 individuals from the Sequenced Treatment Alternatives to Relieve Depression (STAR*D) study were treated with citalopram and genotyped for 53 single nucleotide polymorphisms (SNPs) in a 100-kb region of the OPRM1 gene. The sample consisted of Non-Hispanic Caucasians, Hispanic Caucasians, and African Americans. Population stratification was corrected using 119 ancestry informative markers and principal components analysis. Markers were tested for association with phenotypes for general and specific citalopram response as well as remission. ResultsAssociation between one SNP and specific citalopram response was observed. After Bonferroni correction, the strongest finding was...