Clinical vampirism, more commonly known as Renfield's syndrome, is an obsession with drinking blood. The earliest presentation of clinical vampirism in psychiatric literature was a psychoanalytic interpretation of two cases, contributed by Richard L. Vanden Bergh and John. F. Kelley. As the authors point out, brief and sporadic reports of blood-drinking behaviors associated with sexual pleasure have appeared in the psychiatric literature at least since 1892 with the work of Austrian forensic psychiatrist Richard von Krafft-Ebing. Many medical publications concerning clinical vampirism can be found in the literature of forensic psychiatry, with the behavior being reported as an aspect of extraordinary violent crimes. Source: Wikipedia (en)