1] A pivotal event often leads to the development of vampirism (blood drinking). This usually occurs in childhood, and the experience of bleeding or the taste of blood is found to be "exciting." After puberty, this excitement associated with blood is experienced as sexual arousal.
2] The progression of Renfield's syndrome follows a typical course in many cases:
Autovampirism is generally developed first, usually in childhood, by initially self-inducing scrapes or cuts in the skin to produce blood, which is then ingested, to later learning how to open major blood vessels (veins, arteries) in order to drink a steady stream of warm blood more directly. The blood may then be ingested at the time of the opening, or may be saved in jars or other containers for later imbibing or for other reasons. Masturbation often accompanies autovampiristic practices.
Zoophagia (literally the eating of living creatures, but more specifically the drinking of their blood) may develop prior to autovampirism in some cases, but usually is the next to develop. Persons with Renfield's syndrome may themselves catch and eat or drink the blood of living creatures such as insects, cats, dogs, or birds. The blood of other species may be obtained at places such as slaughter houses and then ingested. Sexual activity may or may not accompany these functions.
Vampirism in its true form is the next stage to develop - procuring and drinking the blood of living human beings. This may be done by stealing blood from hospitals, laboratories, and so forth, or by attempting to drink the blood directly from others. Usually this involves some sort of consensual sexual activity, but in lust-murder type cases and in other nonlethal violent crimes, the sexual activity and vampirism may not be consensual.
3] The compulsion to drink blood almost always has a strong sexual component associated with it.
4] Blood will sometimes take on an almost mystical significance as a sexualized symbol of life or power, and, as such, an experience of well-being or empowerment will be reported by those with Renfield's syndrome following such activities.
5] Persons with Renfield's syndrome are primarily male.
6] The defining characteristics of Renfield's syndrome is the blood-drinking compulsion. Other related activities such as necrophilia and necrophagia that do not have as their goal drinking of blood are not to be considered aspects of this disorder.