The data obtained show that MOH and SA do not share common personality characteristics linked to dependence. Although further studies are needed to understand if such a difference is related to instrumental characteristics or to yet undiscovered psychobiological characteristics of MOH patients; however, we hypothesize that the detected difference may rely on the fact that drug dependence in the 2 groups is promoted by entirely different needs: pleasure seeking in the SA group, pain avoidance in the MOH group.