Two phenotypes were analyzed in the COGA data set: (1) DSM-IV AD and (2) the DSM-IV criterion of withdrawal. Individuals younger than 15 years of age at their most recent interview who were alcohol dependent were excluded for this phenotype, as well as individuals less than 23 years old who did not meet DSM-IV criteria. This was to exclude young children and adolescents not representative of an adult sample as well as individuals not past the primary age of risk. All individuals with SSAGA data for the withdrawal criterion were included in the analysis.
