A psychotic vampire is a person who has a sociopath mental illness that leads him (an exclusive male trait) to behave like a vampire, and sometimes to actually self-identify as one.

In most cases, this identification is with folkloric/fictional vampires such as Dracula, Anne Rice's characters or the vampires in role-playing games. But more usually, psychotic vampires are simply obsessed with blood and will commit brutal crimes without remorse in order to see, taste, and feel it.

Some may also take on the travesty-go of vampyre lifestylers by wearing capes, sleeping in coffins, filling their homes with skulls, bones, and souvenirs stolen from cemeteries through they should not be confused with true lifestylers.

Reported in the medical literature for more than a century and also named Renfield’s syndrome after Stocker’s character, clinical vampirism is a recognizable, although rare, clinical entity characterized by periodic compulsive blood drinking and an affinity with death. The cases documented in the medical literature only refer to those cases in which there is obvious psychosis.

 In those cases in which there is psychosis, the patients have an irresistible urge for blood ingestion, which is a ritual that brings them relief. They believe that by drinking blood they will have an increase in strength and immunity prolonging their life.

In many cases the individual enjoyed drinking their own blood, known as "auto vampirism." Some patients would deliberately wound themselves at the base of the tongue in order to suck at these wounds and swallow the blood.

Clinical vampirism groups some of the most shocking pathological behaviors observed. It is one of the few pathological manifestations that blends myth and reality in dramatic fashion and contains many possible elements including schizophrenia, psychopathic and perverse features.

Several notorious criminals in history are considered by scholars and psychologists to have been psychotic vampires, including Fritz Haarman, Gilles de Rais, the Marquis de Sade, John Haigh, and Elizabeth Bathory. These individuals appear over and over in non-fiction books about vampires.