Power in GWAS: lifting the curse of the clinical cut-off

Although genome-wide association studies (GWAS), in general, facilitated important discovery of new biological knowledge about diseases,1, 2, 3 identified variants for psychiatric disorders explain little variation, and insight into the role of genes in highly heritable psychiatric traits remains poor.4, 5 Low statistical power is seen as the main reason for the failure to locate more variants, and has resulted in a call for larger samples. Our present study, however, shows that better use of (available) phenotypic information can also increase power considerably.