Some psychologists in modern times recognize a disorder called clinical vampirism (or Renfield Syndrome, from Dracula's insect-eating henchman, Renfield, in the novel by Bram Stoker) in which the victim is obsessed with drinking blood, either from animals or humans.

Renfield's Syndrome is described as having four stages:

• a trauma or "critical incident" in childhood in which the patient discovers that the taste and sight of blood is "exciting" or attractive; "autovampirism",
• the drinking of one's own blood (autohemophagia);
• "zoophagia", or the consumption of blood from animals;
• "true vampirism", in which the patient must have human blood, and may resort to stealing blood from medical facilities, or serial murder.