PSMD9 and major depressive disorder: This result is in agreement with those observed in one of the largest genome-wide gene expression study in MDD.19 The results of single-gene association with MDD status, available on request from the National Institute of Mental Health (NIMH) Center for Collaborative Genomic Studies on Mental Disorders, (https://www.nimhgenetics.org/access_data_biomaterial.php), indicated that the mRNA expression levels of PSMD9 gene were decreased in whole blood of MDD patients (nominal P-value=0.02).