As seen in Table 4, the individual DSM-IV criteria provided stronger evidence of association than DSM-IV AD. This suggests that individuals who endorse a specific criterion may have a more common genetic etiology compared with the heterogeneous group of AD individuals, who are diagnosed by endorsing different combinations of DSM-IV criteria. Furthermore, association was observed with a quantitative trait derived from the probability of belonging to the high-risk latent class, despite its lower heritability estimate compared to the heritability of AD. This is consistent with Kuo et al. (Kuo et al., 2008), who found that the first factor derived in a factor analysis was a better fit to a general population of social drinkers when combined with a latent class framework of three classes of drinkers (severe, moderate, and non-problem drinkers).
