consent, all further consenting members of families in which at least three first degree relatives (i.e., proband and two first‐degree relatives) met alcohol dependence lifetime criteria (DSM‐IIIR 9 and Feighner 10 ) were included. Out‐patient clinic recruitment was added shortly after the inception of COGA. To maintain the family‐based structure of the study, comparison families included two parents and at least three children over age 14. 11 Details about the recruitment of participants can be found in paper 2. Sample and Clinical Data in this issue. From the beginning, deep phenotyping of alcohol and other substance use and common psychiatric disorders was included. The Semi‐Structured Interview for the Genetics of Alcoholism 12 (SSAGA) was developed in COGA and has been adopted (sometimes with modification) by many other groups (see, 2. Sample and Clinical Data in this issue for further information on the SSAGA). Another aim of COGA was to link genetic findings to brain function, so neurophysiological assessments of brain function using electro‐encephalograms (EEGs) were included 13 , 14 (see, 3. Brain Function in this issue for further information on COGA brain function studies). These rich data, combined with the family‐based design, have lent themselves to advances in the field
