A Decade in Psychiatric GWAS Research

After more than ten years of accumulated efforts, genome-wide association studies (GWAS) have led to many findings, most of which have been deposited into the GWAS Catalog. Between GWAS’s inception and March 2017, the GWAS Catalog has collected 2,430 studies, 1,818 phenotypes, and 28,462 associated SNPs. We reclassified the psychology-related phenotypes into 198 reclassified phenotypes, which accounted for 472 studies and 6,632 SNPs. In total, 1,109 of the SNPs reached genome-wide significance. Of these, 133 were replicated for the same psychological trait in different studies. Another 379 SNPs were replicated within one original study. The SNPs rs2075650 and rs4420638 were linked to the most replications within a single reclassified phenotype; both were associated with Alzheimer’s disease (AD). Schizophrenia was associated with 76 SNPs. Alzheimer’s disease and schizophrenia were linked to many physical phenotypes, including cholesterol and body mass index, through common GWAS signals. Alzheimer’s disease also shared risk SNPs with age-related phenotypes such as age-related macular degeneration and longevity. Smoking-related SNPs were linked to lung cancer and respiratory function. Alcohol-related SNPs were associated with cardiovascular and digestive system phenotypes and disorders. Two separate studies also identified a shared risk SNP for bipolar disorder and educational attainment. This review revealed a list of reproducible SNPs worthy of future functional investigation. Additionally, by identifying SNPs associated with multiple phenotypes, we illustrated the importance of studying the relationships among phenotypes to resolve the nature of their causal links. The insights within this review will hopefully pave the way for future evidence-based genetic studies.