The present study has several strengths. First, to our knowledge, this is the first study to conduct a systematic comparison of the commonly used dichotomous FH measures with density measures and their associations with alcohol-related clinical (AUD diagnosis), behavioral (age of onset of regular drinking), and neural (P3 amplitude) phenotypes, and examine variations across gender and race/ethnicity. This systematic comparison enabled the discovery of diverse patterns of associations among different FH measures, alcohol outcomes, and diverse social groups. Importantly, the comparison of results across all subjects, males, females, Whites and Blacks allows for testing the general and specific applicability of our findings. Second, to compute the dichotomous and density FH measures, we used subjects’ FH information, alcohol use, AUD symptoms, and diagnosis obtained using only direct interviews. The validity of direct (vs. indirect) FH methods has been shown to be superior (Davies et al., 1997; Vandeleur et al., 2008), thereby ensuring reliability of our findings. Third, the density measures accounted for two variations in the inclusion of affected family members—in one variation, primary and secondary non-descendants were included and in
