on correction for multiple testing (van den Oord 2007). In addition, the estimated magnitude of effect size of genetic variants thought to influence complex behavioral outcomes has been continually shifted downward as studies that were sufficiently powered to detect effect sizes previously thought to be reasonable have failed to generate positive findings (Manolio et al. 2009). GWAS have led the field to believe that genes influencing complex behavioral outcomes likely have odds ratios (ORs) on the order of magnitude of 1.1. This has led to a need for incredibly large sample sizes, requiring meta-analytic GWAS efforts with several tens of thousands of subjects (Landi et al. 2009, Lindgren et al. 2009).
