most of alcohol dependence typologies. Indeed, early onset of alcohol dependence is associated with a family history of alcohol use disorders (Limosin et al., 2001), and some genetic markers may particularly (Edenberg et al., 2008) or specifically (Dahmen et al., 2005) contribute to an earlier onset of the disease. Furthermore, an early age at onset of alcohol dependence is associated with greater impulsivity, more severe dependence (Hingson et al., 2006b), and more severe and frequent alcohol withdrawal complications (Le Strat et al., 2008a). Finally, antisocial behaviors are the most consistent co-morbidity associated with an early onset of alcohol dependence (Kuperman et al., 2005; McGue et al., 2001). These studies have several limitations. For example, they use an arbitrary cut-off, often defined on the basis of clinical rather than epidemiological sample. They also rely on a single distribution model, which might not be appropriate for age-at-onset data (Mayberg et al., 2005). Moreover, some of these studies are based on the age at onset of usual alcohol consumption whereas the onset of alcohol dependence might be clinically more relevant.
