shared environment or other sources of phenotypic variance, and unbiased by cryptic relatedness between individuals, one member of each pair with full-genome SNP-based genetic relatedness estimated at greater than 0.025 was removed from subsequent analyses. For both the set of GABA system SNPs and the full genome-wide set of SNPs, analyses were conducted separately for autosomal markers and markers on the X chromosome. This approach, based on a calculation of genetic relatedness from the simultaneous consideration of all of the SNPs in a particular set, does not provide information regarding the effects of individual SNP effects, but also does not suffer from the inaccuracy of prediction that affects polygenic scores due to error on the estimates of the effects of the individual SNPs that contribute to the score (Visscher et al., 2010).
