Family histories of alcoholism and drug abuse were assessed using the Family History Assessment Module (FHAM), a structured diagnostic instrument to assess major psychiatric disorders among biological first-, second- and third-degree relatives of the informant, originally developed for the Collaborative Study on the Genetics of Alcoholism (COGA; Rice et al., 1995). The screening question for alcoholism was “have any of your relatives ever had any family, job, school, police, or health problems because of drinking?” Similar questions were asked regarding substance abuse. For those relatives identified by the research participant as positive for alcohol and/or substance abuse, specific symptoms of alcohol and drug abuse were assessed using the Individual Assessment Module (IAM) questions related specifically to alcoholism (16 questions) and drug abuse/dependence (14 questions). For the diagnosis of alcoholism or drug abuse/dependence to be considered present, at least three questions had to be scored positively, respectively. Similar information on the density and presence of second-degree family histories of alcoholism and substance abuse was also obtained. Participants also gave written permission to contact several first-degree biological relatives (parents, siblings, children of
