The present study utilized participants from the UCSF Family Alcoholism Study (Seaton et al., 2004; Vieten et al., 2004), which consists of 2524 participants from 890 families (average size = 2.83 members). The UCSF study was a nationwide study on the genetics of alcoholism and other substance dependence designed to recruit a large number of small family pedigrees enriched for alcohol dependence. Probands were sampled from the community and invited to participate if they met screening criteria for alcohol dependence at some point in their lifetime and had at least one sibling or both parents available to participate. Probands were excluded if they reported serious drug addictions (defined as use of stimulants, cocaine, or opiates daily for more than 3 months or weekly for more than 6 months), any history of intravenous substance use, a current or past diagnosis of schizophrenia, bipolar disorder, or other psychiatric illness involving psychotic symptoms (those with depressive and anxiety disorders were accepted), a life-threatening illness, or an inability to speak and read English. Relatives of qualifying probands were invited by mail to participate.
