Tables 1 (primary and secondary phenotypes of DSM-IV AD and criterion count) and 2 (tertiary analysis of seven individual criteria) summarize the samples used in discovery and replication analyses. There were 7,418 (1,114 families) EA and 3,175 (585 families) AA individuals, respectively. In total, there were 18,586 individuals evaluated for DSM-IV AD in both discovery and replication samples, with 7,482 AD cases and 6,169 controls. As shown in Supplemental Table 1 , the primary, secondary and tertiary phenotypes were highly correlated with each other in both EAs and AAs, with DSM-IV AD and DSM-IV AD criterion count having the highest correlations with each individual criterion in both AA and EA subsamples (r>0.87). As shown in Supplemental Table 2, the item response analysis demonstrated that all criteria loaded well on a single underlying AD factor. Some criteria discriminated liability at the lower end of the liability distribution (e.g., Drinking more than intended) while others (e.g., Withdrawal, Time spent drinking, Giving up activities) contributed at the higher end of the severity continuum (Supplemental Text).
