"Clinical vampirism" is the term used by some mental health professionals and therapists to describe vampire-like behavior such as blood drinking, believing one is a supernatural or fictional type of vampire, and so on, whether or not criminal aggression against other people is a factor. Richard Noll, in Vampires, Werewolves and Demons (1991), proposed naming the pattern of escalating "vampire-like" behavior described in psychiatric case histories "Renfield's Syndrome," based on the fly-eating character Renfield in Bram Stoker's Dracula. Renfield's Syndrome is described as having four stages:

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

It's a common misconception in the Vampire Community and among the general public that Renfield's Syndrome is a formal diagnosis recognized by the psychiatric profession. This is completely false. Neither Renfield's Syndrome nor clinical vampirism are included any edition of the Diagnostic and Statistical Manual (DSM). The pattern of clinical vampirism described above is recognized as a phenomenon but is considered a symptom of primary diagnoses such as Antisocial Personality Disorder or a form of psychosis. The term "Renfield's Syndrome" has been popularized by fiction writers and self-proclaimed "experts" in media interviews, giving it an unjustified sheen of authenticity.

Obviously blood-drinking Vampire-Identified People such as Sanguinarians would be summarily labeled by psychiatrists as suffering from this disturbance, which is one reason that members of Vampire Community are extremely wary about revealing their vampiric activities or feelings to mental health professionals.