prevalence of 22%, and further decreases to a daily prevalence of <1%. Second, data from Wave 1 of the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC) suggest that, on average, it takes 5.2 years to progress from initiation of alcohol use to the first symptom of AD (Alvanzo et al., 2011). In the current study, the mean age of first drink in the 42% of subjects who reported drinking is 14.0 ± 1.9 years of age. If the NESARC time frame is applied to this group of drinkers, development of AD would likely occur when these individuals were in their early 20s. Of note, this is consistent with a previous COGA study that found no relationship between AD and GABRA2 until individuals with AD were in their mid-twenties (Dick, Bierut, et al., 2006).
