According to the National Human Genome Research Institute (NHGRI) GWAS catalog, more than 2,000 GWAS have been published to date.42 A total of 14 GWAS have been conducted for either major depressive disorder (MDD) or depressive symptoms. In addition, one GWAS focusing on age at onset of major depressive disorder was conducted. These 15 studies were identified by conducting a systematic search of PubMed for papers published before October 2013. We searched the PubMed database using the following MESH terms: (“Depression”[Mesh] OR “Depressive Disorder”[Mesh] OR “Depressive Disorder, Major”[Mesh] OR “Depressive Disorder, Treatment-Resistant”[Mesh]) AND “Genome-Wide Association Study”[Mesh]. We also searched for articles by examining the references pages of review articles, meta-analyses, and other empirical articles published since 2005. As shown in Table 2, all of these studies were based on samples of European ancestry and represent a combination of population-and clinic-based samples.
