Clinical data relates psychic trauma to the basic characteristics of the personality organisation in patients with drug addiction, most often described as borderline (identity diffusion, partial object relations, domination of primitive defence mechanisms), but extensive research is still lacking. This chapter reviews some important trends in the development of the psychodynamic conceptualisations of addictions, author present our study on the interconnections between the basic personality characteristics of heroin addicted patients and their mentalization capacities. This generation of psychodynamically oriented clinicians concentrates on the clinical reality that patients with drug addiction complain of being either overwhelmed by intolerably painful affects or cut off from their emotions. Interestingly, alexithymia-a concept highly applicable to addictions-is also one of the roots of contemporary mentalization-based theories.