Table 1 presents demographic information for patients, siblings of patients, controls and siblings of controls. For patients and controls mean age was about 16, while for siblings of patients and controls mean age was about 17. Most patients were male (88%), as were controls (84%); about half of the siblings of patients and controls were male. About half of patients and controls were Caucasian and more than one third were Hispanic; the ‘Other’ category includes African Americans (n=16 controls probands and n=36 patient probands), American Indians (n=3 control probands and n=13 patient probands) and Asians (n=2 patient probands). Prevalence of CD was greatest among patients (88%), followed by siblings of patients (38%), controls (16%) and siblings of controls (14%). Rates of lifetime alcohol dependence followed the same pattern.
