|Classification and external resources|
Koro is a culture-specific syndrome delusional disorder in which an individual has an overpowering belief that one's genitalia are retracting and will disappear, despite the lack of any true longstanding changes to the genitals. Koro is also known as shrinking penis, and it is listed in the Diagnostic and Statistical Manual of Mental Disorders. The syndrome occurs worldwide, and mass hysteria of genital-shrinkage anxiety has a history in Africa, Asia, and Europe. In the United States and Europe, the syndrome is commonly known as genital retraction syndrome. The condition can be diagnosed through psychological assessment along with physical examination to rule out genuine disorders of the genitalia that could be causing true retraction.
- 1 Classification
- 2 Etymology and geographical background
- 3 Epidemiology
- 4 Signs and symptoms
- 5 Causes
- 6 History and physical examination
- 7 Diagnosis
- 8 Treatment
- 9 Notable epidemic cases
- 10 Chinese cultural beliefs
- 11 See also
- 12 References
- 13 Further reading
- 14 External links
In DSM-IV-TR, koro is listed as one of the entries in the Glossary of Culture-Bound Syndromes of Appendix I. The manual gives koro's definition as "a term, probably of Malaysian origin, that refers to an episode of sudden and intense anxiety that the penis (or, in females, the vulva and nipples) will recede into the body and possibly cause death." Attempts have been made by numerous authors to place koro into different classes. For example, koro may fit into the group of "specific culture-imposed nosophobia" (classification with cardinal sign), "the genital retraction taxon" (classification with common factors between syndromes), and the group with "culture-related beliefs as causes for the occurrence" (classification according to how the syndromes might be affected by cultural factors).
Various authors have attempted to distinguish between complete and incomplete forms of koro, along with cultural and non-cultural forms. Cultural forms are said to involve a cultural belief or myth which plays a role in the genesis and spread of the disease in the community. These are regarded as complete forms of koro, matching all the symptoms required for diagnosis without significant co-morbidity. Differentiation into primary koro, a culture-bound expression, and secondary koro. Secondary koro is proposed to have co-morbidity with a CNS disorder, another psychiatric disorder, or possible drug use.
Etymology and geographical background
The earliest Western reference to the term koro is found in B.F. Matthes' Dictionary of Buginese Language (1874) of South Sulawesi, Indonesia. The name could derived from a river, its surrounding valley, and a local tribe of the same name which is located at northwestern sector of Sulawesi, Indonesia. The word is also used in Makassarese language, meaning "to shrink"; the full expression is garring koro. Koro may also be derived from Malay term Kura which means "head of turtle" or keruk which means "to shrink". The term shuk yang (缩阳), adapted from Chinese, means "the shrinkage of penis". The term koro is also known as rok loo (genital shrinkage disease) in Thailand, jinjinnia bemar in Assam, India, and lanuk e laso by Bogoba tribe in Philippines.
Among the Chinese, koro is confined to South China and the lower Yangtze Valley. A 1992 study of self-report questionnaires suggests that in the epidemic area of China, koro victims are mostly Han, male, young, single, poorly educated and fearful of supernatural forces and koro. The phenomenon is also found among oversea Chinese in Southeast Asia, especially Malaysia and Indonesia, and less frequently among the Malay and Indonesian inhabitants of the countries. Though there are speculations that the occurrence of koro among people in Malaysia and Indonesia was the result of Chinese migrants, this cultural diffusion view is challenged since koro epidemics have been reported in Thailand and India, involving masses of non-Chinese people.
Sporadic cases of koro among people with non-Southeast-Asian ethnicity have been reported across the globe, for example, Nepali, Sudanese, Jordanian, Tanzanian, Nigerian, French, British, American and Canadian. In most of the non-Chinese cases in the Western hemisphere, genital shrinkage is reported but not all the other typical koro symptoms, such as fear of death, as in endemic countries. The incomplete forms of koro are regarded as the non-cultural forms, while the complete form with acute anxiety is the classical culture-bound type.
Signs and symptoms
Most patients report acute anxiety attacks due to perceived genital retraction and/or genital shrinkage, despite a lack of any objectively visible biological changes in the genitalia that are longstanding. "Longstanding" refers to changes that are sustained over a significant period and do not appear reversible, unlike the effect of cold temperatures on some genital regions that cause retraction. These changes may trigger a koro attack when observed, although the effects of cold temperatures are objectively reversible. According to literature, episodes usually last several hours, though the duration may be as long as two days. There are cases in which koro symptoms persist for years in a chronic state, indicating a potential co-morbidity with body dysmorphic disorder. In addition to retraction, other symptoms include a perception of alteration of penis shape and loss of penile muscle tone. In cases when sufferers have no perception of retraction, some patients may complain of genital paraesthesia or genital shortening. Among females, the cardinal symptom is nipple retraction in the breast, generally into the breast as a whole.
Psychological components of koro anxiety include fear of impending death, penile dissolution and loss of sexual power. Feelings of impending death along with retraction and perceived spermatorrhea has a strong cultural link with Chinese traditional beliefs. This is demonstrated by the fact that Asians generally believe koro symptoms are fatal, unlike most patients in the West. Other ideational themes are intra-abdominal organ shrinkage, sex change to female or eunuch, non-specific physical danger, urinary obstruction, sterility, impending madness, spirit possession and a feeling of being bewitched.
Extremely anxious sufferers and their family members may resort to physical methods to prevent the believed retraction of the penis. A man may perform manual or mechanical penile traction, or "anchoring" by a loop of string or some clamping device. Similarly, a woman may be seen grabbing her own breast, pulling her nipple, or even having iron pins inserted into the nipple. Physical injury may occur from these attempts. These forceful attempts often lead to injuries, even death.
Psychosexual conflicts, personality factors, and cultural beliefs are considered as being of etiological significance to koro. Sexual adjustment histories of non-Chinese victims are often significant, such as premorbid sex inadequacy, sexual promiscuity, guilt over masturbation, and impotence.
Evolutionary and biological mechanisms
When considering the biological mechanisms and evolutionary history of koro, it is important to look at it in the larger framework of mass hysteria. While the underlying mechanisms are still poorly understood, it has been suggested that the mirror neurons play a major role in mass hysteria outbreaks. Mirror neurons, which have been found in both human and non-human primates, are neurons that fire when one performs an action and when they observe another individual performing the same action. It is hypothesized that we evolved these mechanisms to learn from observation of others, as well as to facilitate imitation. However, within mirror neurons, there is some form of inhibitory process, which prevents us from blindly mimicking every action we observe others perform. New research into this area suggests that in mass hysteria outbreaks something goes amiss in this inhibitory process.
History and physical examination
A full medical, psychosexual and psychiatric history should be documented. The physician should explore the patient’s concerns about appearance and body image (ruling out body dysmorphic disorder). Additionally, the physician should inquire about overall beliefs, personal values, and assumptions that the patient is making about his or her genitals. Given that Koro is often an “attack” with a great deal of associated anxiety, the physician should ascertain the patient’s emotional state along with the timeline from onset to the presentation at the examination.
A physical examination should involve an assessment of overall health along with a detailed genital examination. In men, genital examination should be performed immediately after penile exposure, to avoid changes due to external temperature. The primary intent of the male exam is to exclude genuine penile anomalies such as hypospadias, epispadias and Peyronie's disease. The presence of a significant suprapubic fat pad should be noted as well. Careful measurements of flaccid length, stretched length and flaccid girth will also be useful. If male patients insist that their penis is shrinking and disappearing, measurements after intracavernosal alprostadil may be used in the office to determine the true erect length and to diagnose any penile abnormalities in the erect state. A physical examination should note any injuries inflicted by the patient in an effort to "prevent" retraction as further confirmation of Koro.
Several criteria are typically used to make a diagnosis of koro. The primary criteria is a patient's report of genital (typically penile or female nipple) retraction despite a lack of objective physical evidence demonstrating retraction. This is accompanied by severe anxiety related to the retraction, fear of death as a result of retraction, and use of mechanical means to prevent retraction. Cases that do not meet all the requirements are generally classified as koro-like symptoms or given a diagnosis of partial koro syndrome. It has been argued that the criteria are sufficient but not necessary to make a diagnosis of koro. Researchers have identified Koro as a possible "cultural relative" of Body Dysmorphic Disorder. DSM-IV explains the process of differential diagnosis between these two disorders.
Men who present with this complaint may have Koro, but they may also be misinformed about normal genital size. Additionally, they may be suffering from penile dysmorphophobia. Penile dysmorphophobia is related to body dysmorphic disorder (BDD), defined by the Diagnostic and Statistical Manual of Mental Disorders-Fourth Edition (Text Revision) (DSM-IV-TR) as a condition marked by excessive preoccupation with an imaginary or minor defect in a facial feature or localized part of the body. BDD is different from Koro. In Koro, a patient is overcome with the belief that his penis is actively shrinking, and it may be in imminent danger of disappearing. Clinical literature indicates that these two psychological conditions should be separated during differential diagnosis.
In addition to differentiating Koro from body dysmorphic disorder, physicians also recommend that differential diagnosis separates Koro from physical urological abnormalities. For example, one physical disorder that causes loss of penile size is Peyronie's disease, where the tunica albuginea develops scar tissue that prevents the full expansion of an erection and causes flaccid penis retraction. Additionally, a buried penis is a normally developed penis, partially covered by the suprapubic fat which can be surgically removed.
In historical culture-bound cases, reassurance and talks on sexual anatomy are given. Patients are treated with psychotherapy distributed according to symptoms and to etiologically significant points in the past. Prognosis appears to be better in cases with a previously functional personality, a short history and low frequency of attacks, and a relatively uncomplicated sexual life.
For sporadic Western cases, careful diagnostic workup including searching for underlying sexual conflict is common. The choice of psychotherapeutic treatment is based on the psychiatric pathology found.
In China, traditional treatment based on the causes suggested by cultural beliefs are administrated to the patient. Praying to gods and asking Taoist priests to perform exorcism is common. If a fox spirit is believed to be involved, people may hit gongs or beat the person to drive it out. The person will receive a yang- or yin-augmenting Chinese medicine potion, usually including herbs, pilose antler (stag of deer) or deer tail, and tiger penis, deer penis, or fur seal penis. Other foods for therapy are pepper soup, ginger soup and liquor.
Notable epidemic cases
Local official records indicate genital retraction endemics in Hainan Island and Leizhou Peninsula in Guangdong, China, as early as the late 19th century. There were a series of epidemic outbursts in 1948, 1955, 1966, and 1974, whenever there was social tension or impending disaster, followed by the last widespread episode in 1984–1985 and a much smaller outbreak in 1987. The 1984–1985 epidemics lasted for over a year and affected over 3,000 persons in 16 cities and counties. A mental health campaign was conducted for the epidemic and since then no further episodes of the epidemic has occurred in China. Improvement in local economic conditions, associated with a better quality of life, is suggested to contribute to the fading of the episodic occurrences of koro.
A koro epidemic struck Singapore in October 1967 for about ten days. Newspapers initially reported that some people developed koro after eating the meat of pigs inoculated with a vaccine for swine influenza. Rumours relating eating pork and koro spread after a further report of an inoculated pig dying from penile retraction. The cases reported amounted to 97 in a single hospital unit within one day, at five days after the original news report. Government and medical officials alleviated the outbreak only by public announcements over television and in the newspapers.
An epidemic outbreak in November 1976 in Isan, Thailand caused at least 350 cases, most of them Thai and males. Popular opinion and news media echoed the victims' projection of viewing the epidemic as caused by Vietnamese food and tobacco poisoning in a hideous assault against the Thai people. Another large-scale epidemic in Thailand occurred in 1982.
In 1982, a koro epidemic episode in Northeast India affected, in majority, poorly educated people from lower socio-economic strata. There was no evidence of significant premorbid or sexual psychopathology in most cases.
Mass Koro epidemic was reported in Labour Camps in Kochi, Kerala in South India during August and September 2010 among migrant labour population from North and North-east India. Reportedly, the epidemic spread to about 100 individuals in 3 labour Camps within 2 weeks.
In the 1970s and early 1980s, newspapers reported incidents of genital shrinking in Western Nigeria. Since late 1996, a small-scale epidemic of genital shrinking was reported in West African nations. Victims in the African outbreaks often interpreted the experience as genital theft, accusing someone with whom they had contact of "stealing" the organ and the spiritual essence, causing impotence. The perceived motive for theft was associated with local occult belief, the witchcraft of juju, to feed the spiritual agency or to hold the genital for ransom. Social representations about juju constitute consensual realities that propose both a means and motivation for genital-shrinking experience.
The epidemic began in Nigeria and Cameroon, and spread to Ghana, Ivory Coast and Senegal by 1997. Cases were reported in Cotonou, Benin where mobs attacked individuals accused of the penis theft and authorities ordered security forces to curb the violence, following the deaths of five people by vigilantes. Later reports of outbreak suggest a spread beyond West Africa, including the coverage of episodes in Khartoum, Sudan in September 2003; Banjul, Gambia in October 2003; and Kinshasa, DR Congo in 2008.
Comparing West African genital-shrinking epidemics with koro in Southeast Asia, the latter has symptoms centered on genital retraction (instead of shrinkage) and fear of death (which is absent in African cases). A study analyzing the West African epidemics from 1997 to 2003 concluded that rather than psychopathology, the episodes were product of normal psychological functioning in undisturbed individuals, who were influenced by the local cultural models or social representations.
U.S. and Europe
In the late Middle Ages in Europe, it was believed that men could lose their penises through magical attacks by witches. The Malleus Maleficarum, a 15th-century European manual for witchcraft investigations, relates stories of men claiming that their genitals had disappeared, being "hidden by the devil … so that they can be neither seen nor felt." They were said to have reappeared after the men had appeased the witches responsible. Witches were said to store the removed genitals in birds' nests or in boxes, where "they move themselves like living members and eat oats and corn".
At least three publications of the 1880s, from U.S., Russia and England, reported genital retraction pathology, without using the Malay or Chinese term. Koro epidemics in China were first noticed in a French report in 1908 and descriptions of koro entered clinical books of western medicine in 1936. In the 1950s, koro is noted in nosological and diagnostic psychiatry.
Chinese cultural beliefs
Most of the ancient literature concerning koro was related to Chinese ethnic groups. For example, koro (in its Chinese term of shuk yang) is documented in the old medical book New Collection of remedies of value (simplified Chinese: 验方新篇; traditional Chinese: 驗方新篇) which was published in Qing Dynasty. The book described the condition as "yin type of cold qi invasion" (simplified Chinese: 阴症伤寒; traditional Chinese: 陰症傷寒) which involved a sudden seizure during sexual intercourse with the penis retracting into the abdomen. It asserts that the patient will die if not treated with "heaty" drugs in time.
Factors of cultural expectation in the genesis of koro can be built upon ideas of sex physiology in the traditional Chinese medicine, with free play of imagination which links fatality with genital retraction.
In the ancient Chinese medical book Zhong Zang Jing (simplified Chinese: 中藏经; traditional Chinese: 中藏經), retraction of the penis with distension of the abdomen was described as a certain sign of death. The yin and yang theory proposes that an unbalanced loss of the yang humour produces genital shrinkage.
In Taoism and Traditional Chinese medicine, frequent ejaculation is regarded as detrimental to health, as semen is considered to be related to a man's vital energy, and hence excessive depletion of semen may lead to illness or death. Some authors believe that the idea of death caused by the semen depletion resembles the idea of death caused by genital disappearance, although such linkage between koro and Taoism, which influences Chinese medicine to some degree, is only speculative.
The popularity of Chinese folklore also plays a role. The novel about ghost stories Strange Stories from a Chinese Studio describes a fox spirit which can make people weak physically and sexually and shrink their tissues. Belief in koro being caused by the fox ghost among the southern Chinese has been reported.
- Shenkui, a similar Chinese culture-bound syndrome
- Castration anxiety
- Culture-bound syndrome
- Diagnostic and Statistical Manual of Mental Disorders
- Traditional Chinese Medicine
- Mental health in China
- American Psychiatric Association (2000). Diagnostic and Statistical Manual of Mental Disorders, 4th ed., text revision. American Psychiatric Pub. pp. 898–901. ISBN 978-0-89042-025-6.
- "Koro". dictionary.com. Retrieved April 1, 2013.
- Mattelaer, Johan J.; Jilek, Wolfgang (2007). "Koro?The Psychological Disappearance of the Penis". The Journal of Sexual Medicine. 4 (5): 1509–1515. ISSN 1743-6095. doi:10.1111/j.1743-6109.2007.00586.x.
- "Top 10 Little-Known Mental Disorders". Discovery Communications. Retrieved 15 July 2012.
- Chowdhury AN (1996). "The definition and classification of koro". Cult Med Psychiatry. 20: 41–65. doi:10.1007/bf00118750.
- Ghanem, H., Glina, S., Assalian, P., & Buvat, J. (2012). Position Paper: Management of Men Complaining of a Small Penis Despite an Actually Normal Size. The Journal of Sexual Medicine.
- Yap, Pow-Meng (1967), "Classification of the Culture-Bound Reactive Syndromes", Australian and New Zealand Journal of Psychiatry, 1 (4): 172–9, ISSN 0004-8674, doi:10.3109/00048676709159191
- Simons, Ronald C.; Hughes, Charles C. (1985). The Culture-bound syndromes: Folk Illnesses of Psychiatric and Anthropological Interest. Dordrecht, Holland: D. Reidel Publishing Company. pp. 485–6. ISBN 90-277-1858-X.
- Tseng, Wen-Shing (2001), Handbook of Cultural Psychiatry, San Diego: Academic press, ISBN 0-12-701632-5
- Adeniran, R. A.; Jones, J. R. (April 1994), "Koro: Culture-Bound Disorder or Universal Symptom?", British Journal of Psychiatry, 164 (4): 559–61, ISSN 0007-1250, doi:10.1192/bjp.164.4.559
- Chowdhury, Arabinda N. (March 1996), "The definition and classification of Koro", Culture, Medicine & Psychiatry, 20 (1): 41–65, ISSN 0165-005X, doi:10.1007/bf00118750
- Wang, Minghui; Wang, Fenglei (March 2002), "Conceptualisation and treatment of koro in traditional Chinese medicine", The Chinese Journal of Human Sexuality (in Chinese), 11 (1): 559–61, ISSN 1672-1993
- Chowdhury, Arabinda N. (September 1998), "Hundred Years of Koro: The History of a Culture-Bound Syndrome", The International Journal of Social Psychiatry, 44 (3): 181–8, ISSN 0020-7640, doi:10.1177/002076409804400304
- Durst, Rimona (1991). "The Disorder Named Koro" (PDF). Behavioural Neurology. 4 (1): 1–14. PMID 24487349. doi:10.3233/BEN-1991-4101. Retrieved 3 June 2015.
- Cheng, Sheung-Tak (March 1996), "A Critical Review of Chinese Koro", Culture, Medicine & Psychiatry, 20 (1): 41–65, ISSN 0165-005X
- Palthe, W. P. M. van (1934), "Koro, een Eigenaardige Angstneurose", Geneeskundig Tijdschrift voor Nederlandsch-Indie, 74: 1713–1720
- Yap, Pow-Meng (1965), "Koro – A Culture-Bound Depersonalization Syndrome", British Journal of Psychiatry, 111: 45–50, ISSN 0007-1250, doi:10.1192/bjp.111.470.43
- Tseng, W. S. (December 2006), "From Peculiar Psychiatric Disorders through Culture-bound Syndromes to Culture-related Specific Syndromes", Transcultural Psychiatry, 43 (4): 554–576, doi:10.1177/1363461506070781
- Chowdhury, A. N.; Rajbhandari, K. C. (1994), "Koro with Depression in Nepal", Transcultural Psychiatric Research Review, 32: 87–90, doi:10.1177/136346159503200108
- Baasher, T. A. (1963), "The Influence of Culture on Psychiatric Manifestation", Transcultural Psychiatric Research Review, 15: 51–2
- Al-Hmoud, N. (1999), "Koro-like syndrome in a Jordanian male", Eastern Mediterranean Health Journal, 5 (3): 611–3
- Lucieer, W. M. (1984), "The Bitter Taste of Liberty: A Study in Ethnopsychiatry", Psychopathologic Africane, 20: 17–40
- Ifabumunyi, O. I.; Rwegellera, G. G. C. (1979), "Koro in a Nigerian Male Patient: A Case Report", African Journal of Psychiatry, 5: 103–5
- Burgeois, M. (1896), "Un Koro Charentais (Transposition Ethnopsychiatrique)", Annales médico-psychologiques, 126: 749–51
- Barrett, K. (1978), "Koro in a Londoner", The Lancet, 8103 (2): 1319, doi:10.1016/s0140-6736(78)92093-7
- Yap, Pow-Meng (August 1965), "Koro in a Briton", British Journal of Psychiatry, 111 (477): 774–5, ISSN 0007-1250, doi:10.1192/bjp.111.477.774-a
- Cremona, Anne (February 1981), "Another case of koro in a Briton", British Journal of Psychiatry, 138 (2): 180–1, ISSN 0007-1250, doi:10.1192/bjp.138.2.180
- Bychowski, G. (1952), Psychotherapy of Psychosis, New York: Grune and Stratton, pp. 109–10
- Edwards, J. G. (1970), "The Koro pattern of depersonalization in an American schizophrenic patient", American Journal of Psychiatry, 126: 1171–3, PMID 5411375, doi:10.1176/ajp.126.8.1171
- Dow, T. W.; Silver, D. (1973), "A drug induced Koro syndrome", Journal of Florida Medical Association, 60: 32–3
- Ede, A. (1976), "Koro in an Anglo-Saxon Canadian", Canadian Psychiatric Association Journal, 21: 389–92
- Kumar, H. V. (January 1987), "Koro in an Israeli Man", British Journal of Psychiatry, 150 (1): 133b, ISSN 0007-1250, doi:10.1192/bjp.150.1.133b
- Ngui, P. W. (1969), "The Koro Epidemic in Singapore", Australian and New Zealand Journal of Psychiatry, 3 (3a (special issue on studies of anxiety)): 263–6, ISSN 0004-8674
- Chowdhury, Arabinda N. (1992), "Clinical Analysis of 101 Koro Cases", Indian Journal of Social Psychiatry, 8: 67–70
- Mattelaer, J. and Jilek, W. (2007, September). Koro—The psychological disappearance of the penis. Retrieved March 5, 2013, from Ebscohost Database.
- Gwee, Ah Leng (1963), "Koro – A Cultural Disease", Singapore Medical Journal, 4: 119–22
- Garlipp, Petra (2008), "Koro – a Culture-Bound Phenomenon Intercultural Psychiatric Implications", German Journal of Psychiatry, 11: 21–8, ISSN 1433-1055
- Berrios, G. E.; Morley, S. (September 1984), "Koro-like Symptoms in Non-Chinese Subjects", British Journal of Psychiatry, 145 (3): 331–4, ISSN 0007-1250, doi:10.1192/bjp.145.3.331
- Lee, Yao-Tung and Tsai, Shih-Jen, The mirror neuron system may play a role in the pathogenesis of mass hysteria, Medical Hypotheses 2010, p 244
- Berrios GE, Morley SJ (1984). "Koro-like symptom in a non-Chinese subject". Br J Psychiatry. 145: 331–4. doi:10.1192/bjp.145.3.331.
- Wylie K. R., Eardley I. (2007). "Penile size and the 'small penis syndrome'". BJU international. 99 (6): 1449–1455. PMID 17355371. doi:10.1111/j.1464-410x.2007.06806.x.
- Jilek WG, Jilek-Aall L (1977). "A koro epidemic in Thailand". Transcult Psychiatr Res Rev. 14: 57–9. doi:10.1177/136346157701400110.
- Elder JS. Congenital anomalies of the genitalia. In:Walsh PC, Retik AB, Walsh PC, Campbell MF, eds. Campell’s urology. Philadelphia, London, Toronto: W.B. Saunders Comp.; 1998: 2120–43.
- Dzokkoto, Vivian Afi; Adams, Glenn (2005), "Understanding genital-shrinking epidemics in West Africa : koro, juju or mass psychogenic illness?", Culture, Medicine and Psychiatry, 29 (3): 53–78, ISSN 0165-005X, doi:10.1007/s11013-005-4623-8
- Spyropoulos E, Christoforidisb C, Borousasa D, Mavrikosa S, Bourounisa M, Athanasiadisa S (2005). "Augmentation phalloplasty surgery for penile dysmorphophobia in young adults: Considerations regarding patient selection, outcome evaluation and techniques applied". Eur Urol. 48: 121–8. doi:10.1016/j.eururo.2005.02.021.
- Ang PC, Weller MP (1984). "Koro and psychosis". Br J Psychiatry. 145: 335. PMID 6478130. doi:10.1192/bjp.145.3.335.
- Kim J, Kim M, Lee N, Park Y (2000). "A case of urethrocutaneous fistula with the koro syndrome". J Urol. 164: 123. doi:10.1016/s0022-5347(05)67465-4.
- Brock Gerald; et al. (1997). "The anatomy of the tunica albuginea in the normal penis and Peyronie's disease". The Journal of Urology. 157 (1): 276–281. doi:10.1016/s0022-5347(01)65359-x.
- Greenfield Jason M.; Lucas Steven; Levine Laurence A. (2006). "Factors affecting the loss of length associated with tunica albuginea plication for correction of penile curvature". The Journal of Urology. 175 (1): 238–241. doi:10.1097/00005392-200601000-00078.
- Fishbain, D., Barsky, S., and Goldberg, M. (January, 1989). "Koro" (genital retraction syndrome): Psychotherapeutic interventions. Retrieved March 25, 2013, from EBSCOhost. 
- Fishbain, David A.; Barsky, Steve; Goldberg, Myron (January 1989), "'Koro' (Genital Retraction Syndrome): Psychotherapeutic Interventions", American Journal of Psychotherapy, 43 (1): 87–91, ISSN 0002-9564
- Koro study team (December 1969), "The Koro "Epidemic" in Singapore", Singapore Medical Journal, 10 (4): 234–42
- Ng, B. Y. (August 1969), "History of Koro in Singapore", Singapore Medical Journal, 38 (8): 356–7
- Lee, Teh Jen (11 March 2012). "The year S'pore men feared for their penises". The New Paper. Archived from the original on 3 June 2015. Retrieved 3 June 2015.
- Jilek, W.; Jilel-Aall, L. (1977), "Mass-hysteria with Koro-symptoms in Thailand", Schweizer Archiv für Neurologie, Neurochirurgie und Psychiatrie, 120 (2): 257–9
- Sachdev, P. S. (December 1985), "Koro Epidemic in North-East India", Australian and New Zealand Journal of Psychiatry, 19 (4): 433–8, ISSN 0004-8674, doi:10.1080/00048678509158852
- "Benin alert over 'penis theft' panic", BBC News, 27 November 2001, retrieved 26 January 2010
- Panic in Khartoum: Foreigners Shake Hands, Make Penises Disappear, The Middle East Media Research Institute, 22 October 2003, retrieved 26 January 2010
- Lynchings in Congo as penis theft panic hits capital, Reuters Africa, 23 April 2008, retrieved 2 May 2008
- Malleus Maleficarum Part II, Question I, Chapter VII
- Cheng S.T. (1996). "A Critical Review of Chinese Koro". Culture, Medicine and Psychiatry. 20: 67–82. doi:10.1007/bf00118751.
- Michael W. Passer & Ronald E. Smith. "Sociocultural factors for Anxiety disorder". Psychology - The science of mind and behaviour (3rd ed.). p. 542.
- Ang, PC; Weller, MPI (September 1984). "Koro and psychosis". The British Journal of Psychiatry. Royal Medico-psychological Association. 145 (3): 335. ISSN 0007-1250. PMID 6478130. doi:10.1192/bjp.145.3.335.
- Koro Syndrome
- Koro: A Natural History of Penis Panics, September 16, 2002, Kuro5hin
- Wall Street Journal's "Best of the Web Today," Wednesday, October 22, 2003
- Koro - the Genital Retraction Syndrome - BBC h2g2, Page dedicated to Koro
- A mind dismembered: In search of the magical penis thieves, Harper's Magazine, Frank Bures, June 2008.