AUBs are dynamic phenomena that unfold in different ways across the lifespan, with strong age-related trends in prevalence as well as substantial between-individual and betweencohort variability in these trends (10–18). Alcohol addiction is similarly dynamic, thought to involve three distinct stages of neurobiological adaptation that correspond to changes in motivations for drinking and compulsivity of alcohol use (19). Genetic epidemiology studies in twins have established that the heritability of AUBs changes across the lifetime, with the relative importance of genes increasing until a plateau in middle adulthood (20), followed by a slight drop-off in older adulthood (21). Some evidence suggests that there are also qualitative changes in which genes affect AUBs at different life stages (15, 22, 23). Certainly, the varying pattern of risk/protective factors for AUBs across the lifespan, such as (legal) access to alcohol, social drinking habits, and prevalence of disorders that co-occur with alcohol use (24), suggests that the underlying causes of AUBs - both genetic and environmental - are developmentally dynamic.
