Alcohol dependence has long been recognised to aggregate in families (Bierut et al.,1998; Merikangas et al., 1998; Nurnberger et al., 2004). A genetic component in alcoholism is supported by twin studies (Heath et al., 1997; Nelson et al., 2004; Prescott et al., 1997; Xian et al., 2008) as well as adoption studies (Cloninger et al., 1981; Goodwin et al. 1973, Goodwin et al., 1974; King et al., 2009).
