Limitations of the study include the fact that all analyses are based on self-report and there is no independent corroboration of diagnoses or symptoms. Subjects interviewed in their late 20s may have had more difficulty with accurate reporting of events in early teenage years in comparison to subjects in their mid-teens. Retention rate from baseline interview to two-year interview was 85%, the majority of subjects completed at least four interviews ([23] Bucholz et al., 2017). Families in the COGA study tend to be densely affected and results may not be generalizable to persons with alcohol use disorder in the general population. The subjects were ascertained at 7 University-based clinical sites (State University of New York, Brooklyn, University of Iowa, Iowa City, Indiana University School of Medicine, Indianapolis, Washington University in St. Louis, University of California San Diego, University of Connecticut, Hartford, and Howard University, Washington DC) and the populations studied reflect those sites.
