The Collaborative Study on the Genetics of Alcoholism (COGA) is an ongoing multi-site study that has recruited families at centers across the United States. To limit heterogeneity a sample of 1,923 European American subjects from 219 families was used in the present analysis; they were recruited at Indiana University, State University of New York Downstate Medical Center, University of Connecticut, University of Iowa, University of California/San Diego, and Washington University, St. Louis. This study was approved by the institutional review boards of all participating institutions. Each family was ascertained through a proband seeking treatment at an alcohol treatment program (Begleiter et al., 1995; Foroud et al., 2000; Nurnberger, Jr. et al., 2004; Reich et al., 1998).
