Figure 2a shows the temporal trends in the publication dates for these studies. Figure 2b illustrates a number of properties of the findings from the literature. Note that only ~15% of the SNP-disease associations are detectible with 90% power with a sample of 1,000 cases and 1,000 controls whereas only about 4% would not be detected with 25,000 cases and 25,000 controls (the estimated number of GWAS samples available for schizophrenia and bipolar disorder by 2014). This point is crucial – based on power calculations and empirical findings for other disorders, “failure” to detect an association is meaningful only if the sample size is very large.
