A Collection of Strange Beliefs, Amusing Deceptions, and Dangerous Delusions

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koro (shook yang)

Koro is a psychological disorder characterized by delusions of penis shrinkage and retraction into the body, accompanied by panic and fear of dying. This delusion is rooted in Chinese metaphysics and cultural practices. The disorder is associated with the belief that unhealthy or abnormal sexual acts (such as sex with prostitutes, masturbation, or even nocturnal emissions) disturb the yin/yang equilibrium which allegedly exists when a husband has sex with his wife, i.e., during "normal intercourse." This disturbance of metaphysical harmony (loss of yang) manifests itself in penis shrinkage. Yang is the vital essence of the male and when inappropriately expelled, it is believed, the result is a potentially fatal dose of koro.

Koro is also thought to be transmitted through food. In 1967, there was a koro epidemic in Singapore after newspapers reported cases of koro due to eating pork which came from a pig that had been inoculated against swine fever. Not only did pork sales go down, but hundreds of koro cases followed. The power of the press to cause panic was matched by their equal power to quell the imbalance they had caused. They gave ample access to the Singapore Medical Association and Ministry of Health who convinced the people that koro was a result of fear, thus ending the epidemic.

further reading

books and articles

Bartholomew, Robert E. "The Medicalization of Exotic Deviance: A Sociological Perspective on Epidemic Koro," Transcultural Psychiatry 35(1):5-38, March 1998.

Bartholomew, Robert E. and Benjamin Radford. "Genital Shrinking Scares," in Hoaxes, Myths, and Manias - Why We Need Critical Thinking (Prometheus  Books 2003).

Rubin, Robert T. Extraordinary Disorders of Human Behavior, edited by Claude T. H. Friedmann and Robert A. Faguet (NY & London: Plenum Press, 1982).


Koro: A Natural History of Penis Panics

Suo yang (Koro): The Genital Retraction Syndrome

Last updated 09-Feb-2014

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