et al., 2011) indicate that somewhat more than half the heritable variance for these traits can be accounted for by common SNPs. GCTA estimates for personality (Vinkhuyzen et al., 2012) and schizophrenia (Lee et al., 2012) suggest that less than half the heritable variance is being accounted for. In our case, for only one phenotype (Illicit Drugs) was the GCTA estimate (.37) at least 50% of the biometric estimate (.55). For the other phenotypes, the GCTA estimate ranged from 40% of the biometric estimate (for Behavioral Disinhibition) to only 11% of the estimate for Alcohol Dependence. While it is important to emphasize that the confidence intervals associated with the GCTA estimates are broad, these findings when combined with previous results for schizophrenia and personality suggest that much of the heritable variation for some behavioral phenotypes cannot be captured by common SNPs.
