Biological parents’ and grandparents’ lifetime history of AUD was obtained from both parents and participant using the FHAM. Most participants had 2 biological parents as informants, and all participants had at least one. For each participant, an index of FH density was computed: each parent with a history of AUD contributed 0.5 and each grandparent with AUD history added 0.25 to the score (range 0 to 2) (Zucker et al., 1994). Stoltenberg et al. (1998) found this density measure provided a valid characterization of familial AUD and may provide greater sensitivity than categorical approaches.
