Alcohol consumption is influenced in part by genetic factors: heritability (h2) estimates for alcohol consumption in adults range from about 0.2 to 0.6 (Kendler et al. 2008b, 2010; Grant et al. 2009; Dick et al. 2011; Geels et al. 2012). For adolescents, heritability estimates for alcohol-related phenotypes vary considerably. Some studies have found that the h2 of alcohol use is quite low (0.1 or lower) (Rhee et al. 2003), while others have reported moderate estimates (0.3–0.5) for frequency of use (Viken et al. 1999; Pagan et al. 2006), frequency of intoxication (0.4–0.7) (Edwards et al. 2011a) and quantity of use (0.6) (Fowler et al. 2007). High levels of alcohol consumption can be a key predictor of alcohol problems (Dawson, 1994; Whitfield et al. 2004; Dawson et al. 2005), and these phenotypes are highly genetically correlated (Whitfield et al. 2004; Grant et al. 2009; Kendler et al. 2010; Dick et al. 2011). Thus, though alcohol use per se does not necessarily predict the development of problems, excessive consumption can be an indicator of genetic liability to problems.
