The samples included in this study were recruited and tested as part of the multi-site Collaborative Study on the Genetics of Alcoholism (COGA), a national consortium designed to study the genetic predisposition to develop alcoholism and related phenotypes. Data from seven COGA sites were included in the analysis: SUNY Downstate Medical Center at Brooklyn, New York; University of Connecticut Health Center; Washington University School of Medicine in St. Louis; University of California at San Diego; University of Iowa Carver College of Medicine; Indiana University School of Medicine; and Howard University College of Medicine. Institutional review boards at each site approved the research protocols in the COGA study and written consent was obtained from each individual prior to participation.
