An unselected general population sample of 147 individuals with similar demographic characteristics to the family sample (58% female, 92% Caucasian) was recruited to assess phenotype base rates. Letters were sent to residents of the same geographical areas as the family samples, requesting participation in a study on “health behaviors and characteristics” to avoid a sample biased toward participation in a study on alcoholism. No inclusion/exclusion criteria were applied. Twenty-four (16%) control participants met criteria for DSM-IV alcohol dependence, which is similar to the prevalence rate for the disorder reported in larger epidemiological studies (e.g., Hasin et al., 2007).
