Total heritability estimates for the different scales range from 0.28 to 0.36, as obtained from an additive genetic + residual (AE) model based on a large twin-sibling study (N~13,000; Keller et al. 2005). These are essentially estimates of broad-sense heritability and include any nonadditive genetic variance (separate unbiased estimates of additive and nonadditive genetic influences are not available), whereas the GCTA heritability estimates from the SNPs (h2SNPs) do not include nonadditive genetic variance – this is considered further in the Discussion section.
