Consistent with the existing literature, early onset of alcohol dependence was associated with antisocial disorders. Schuckit and Irwin indeed proposed that one type of alcohol dependence (Cloninger’s type II) is characterized mainly by antisocial behaviours more than by alcohol related symptoms (Schuckit and Irwin, 1989). Alcohol dependent patients with an early onset of dependence are more likely to have impaired decision making, higher impulsivity, even when controlled for comorbid drug abuse and age at interview (Dom et al., 2006). These characteristics are partially underlied by genetic factors (for a more complete review, see (Kreek et al., 2005)). The fact that the bimodal distribution of ages at onset of alcohol dependence is maintained, with a non significantly different cut-off, when excluding all patients with antisocial personality disorder, is pleading against the hypothesis that Cloninger’s type II is mainly explained by antisocial personality disorder. Furthermore, the direct evidence (e.g. without correcting for confounding factors) of early versus late onset of alcohol dependence reinforce these two classifications regarding co-morbidity, with more anxious and mood disorders in the later onset group, and more ASPD,
