In summary, we found that the distribution of age at onset in alcohol dependence revealed two subgroups of patients. The optimal cut-off of age at onset of alcohol dependence in this sample is 22 years, which correctly classified two thirds of each group. Future typologies, including DSM-V, could take this cut-off into account in order to improve their accuracy, when efficacy and specificity rather than sensitivity is the priority, for examples in order to matched treatment or in the analysis of complex markers.
