Edit concept Question Editor Create issue ticket


Koro refers to the overwhelming belief by an individual that his or her genitalia are retracting or disappearing, without any physical evidence as confirmation. This condition is typically accompanied by severe anxiety


 The clinical picture typically consists of an acute anxiety attack that stems from the delusional perception of penile retraction or disappearance although there is no longstanding physical evidence. Longstanding describes a chronic and irreversible change. Note that cold temperature on the genitals can lead to reversible retraction that may induce a Koro attack.

The duration of a Koro attack ranges from several hours to 2 days [8]. In persistent cases, Koro continues for years, which is suggestive of a coexisting BDD [2].

Other than retraction, some patients imagine a change in the shape of the penis and its loss of tone. Also, there are cases in which individuals report paresthesia or shrinkage of the genitals as opposed to retraction. As for Koro in females, the main feature is the perception of nipple retraction into the breast [5].

Those who follow traditional Chinese principles believe that penile retraction, spermatorrhea, and inevitable death are part of the psychiatric disorder. The resultant anxiety is precipitated by the patient's beliefs of impending death, disappearance of genitals, and loss of sexual function. In contrast, Western patients do not typically associate death with this disorder.

Further manifestations include the perception of the abdominal organ shrinkage, gender transformation, urinary obstruction, and sterility. Patients may suspect imminent psychosis, physical harm, and bewitchment.

Another feature is the response of the patients and their family members who may perform physical or mechanical maneuvers to fix the retraction. For example, males may use a string or a clamp to anchor the penis [9], while females may pull their nipples out or place iron pins into the nipples. All of these interventions can cause serious injuries and sometimes death.

Physical exam
The examination consists of full inspection of the genitals including any self-inflicted harm or injury secondary to the correction of the perceived defect.

Inguinal Hernia
  • A case of Koro is described in an elderly person with associated inguinal hernia and schizophrenia. Its aetiology and origin are traced in Chinese culture, to the Chin Dynasty. A nosology for the classification of Koro Syndrome is proposed.[ncbi.nlm.nih.gov]
Psychiatric Manifestation
  • “The influence of culture on psychiatric manifestations.” Transcultural psychiat. Res., No. 15, 51 – 52. Berne, E. ( 1960 ). “The cultural problem: psychopathology in Tahiti.” Amer. J. Psychiat., 116, 1076 – 1081. Brero, P. C. J. van ( 1897 ).[doi.org]
  • “The influence of culture on psychiatric manifestations.” Transcultural psychiat. Res. , No. 15 , 51 – 52 . Berne , E. ( 1960 ). “The cultural problem: psychopathology in Tahiti.” Amer. J. Psychiat. , 116 , 1076 – 1081 . Brero , P. C.[cambridge.org]
  • A. 1963 The Influence of Culture on Psychiatric Manifestation. Transcultural Psychiatric Research Review 15: 51–52. Google Scholar Barrett, K. 1978 Koro in a Londoner. The Lancet 2, 8103: 1319. Google Scholar Beale, S., M. Lisper and B.[doi.org]
Abnormal Behavior
  • In Normal and Abnormal Behavior in Chinese Culture. A. Kleinman and T.-Y. Lin, eds. Boston: D. Reidel Publishing Co. Google Scholar Wu, Y.[doi.org]
  • .), Normal and abnormal behavior in Chinese culture (pp. 371 - 386 ). Dordrecht : D. Reidel. Google Scholar Crossref Teicher, M. I. ( 1960 ).[doi.org]
Nipple Retraction
  • Koro can also be referred to as Nipple Retraction Syndrome when it “affects” females. However, it is very rare among females of these regions. Koro is the fear of a man’ penis (woman’s nipples) shrinking and gradually absorbed by his/her body.[anthropology.msu.edu]
  • As for Koro in females, the main feature is the perception of nipple retraction into the breast.[symptoma.com]
  • 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.[en.wikipedia.org]
Scrotal Pain
  • This case report describes a case of Koro syndrome associated with penile and scrotal pain. A review of the literature has not shown any previous report of Koro associated with genital pain.[ncbi.nlm.nih.gov]
  • The Neglect of Culture in Psychiatric Nosology : the Case of Culture Bound Syndromes . International Journal of Social Psychiatry, Vol. 41, Issue. 4, p. 235. CrossRef Google Scholar Ilechukwu, Sunny T.C. 1992.[doi.org]


The clinician should obtain the patient's full history including a focused psychiatric assessment. Also, the clinician should ascertain the patient's beliefs and attempt to understand the deep-seated roots of his or her perceptions. Furthermore, a physical exam of the genitals should be performed, and the medical team should be alerted to any injuries that may have occurred from repairing the believed retraction.

Diagnostic criteria
The diagnosis of Koro is achieved when several criteria are met: 1) the perceived retraction of the penis or female nipple is not confirmed on physical examination, 2) presence of profound anxiety as a consequence of the retraction, 3) fear of death secondary to the retraction, and 4) the use of manual or mechanical techniques to prevent further genital withdrawal [10]. When a patient does not display all of the above, he/she is diagnosed with partial Koro syndrome.

Differential diagnoses
Koro has been described as a "cultural relative" of BDD. The Diagnostic and Statistical Manual of Mental Disorders-Fourth Edition (Text Revision) (DSM-IV-TR) outlines the difference between these two disorders. Moreover, while men who report retraction may suffer from Koro, the clinician should consider the patient's misconceptions regarding normal penis size. They may exhibit penile dysmorphophobia, a form of BDD. The latter condition is defined as a marked obsession with an imaginary or a small imperfection on the face or another part of the body.

Another essential component of the workup includes the assessment and exclusion of urologic abnormalities [11] such as Peyronie's disease. Another differential includes a buried penis, in which suprapubic fat conceals the organ.


The therapeutic approach of Koro and Koro-like features depends on the etiology and the geographical location.

In the United States and other Western cultures, psychotherapy is the initial therapy, while the traditional treatment in the Chinese culture involves the use of Shaman Healers or the Fold Sector, who may perform exorcism or prayers. Additionally, the affected individual is provided with a yin or yang potion for consumption as well as a special diet consisting of pepper soup, ginger soup, and liquor.

In sporadic Koro, the underlying psychiatric disease requires treatment with antipsychotics and antidepressants, which have proved to be successful. Antipsychotic drugs cured the sensation of retraction and its associated anxiety, however, other schizophrenic signs, such as auditory and somatic hallucinations, remained.


Individuals with a brief psychotic disorder are associated with good prognosis, especially in those without underlying psychiatric diseases. Moreover, favorable outcomes are observed in patients who experience an abrupt onset and a short period of symptoms. Also, some European studies suggest that a significant percentage of patients do not experience recurrent psychiatric illnesses.

However, one should remain vigilant that brief psychotic disorder and all other mental health illnesses are linked with an elevated risk of self-injury or harm to others [6], especially in patients with affective signs. Additionally, brief psychotic disorder may be a feature of a severe psychotic disease [7].


In-depth studies about Koro have revealed a deep connection to culture as explained below. Additionally, psychodynamics may play a role as well.

Cultural beliefs
While the Western cultures do not endorse the idea about genital disappearance, contemporary medicine in Asia and Africa describes this condition, which dates back to the medieval period in Europe [1]. Specifically, the etiology of Koro depends on the beliefs of specific countries. According to these beliefs, the causes can be the female fox spirit in China, mass poisoning in Singapore and Thailand, and sorcery in Africa.

Furthermore, certain cultures believe that retraction or shrinkage of the penis results in impotence, sterility, and even death. Additionally, various ethnicities and religions in Asia and Africa regard the reproductive function as a mark of the individual's personal value. Specifically, in China, the traditional medical ideologies consider that a decrease in the male yang will disrupt the yin-yang equilibrium. Hence, Koro is acknowledged as a "culture-bound" disorder in China.

Psychodynamic beliefs
The delusional belief of genital retraction may be based on the guilt associated with fantasizing about or performing forbidden sexual activities such as extramarital sex, intercourse with sex workers, or masturbation. It is thought that these prohibited actions interfere with the yin-yang equilibrium, which is established through marital sex.

Some cultures believe that Koro is transmitted through food.


Koro is prevalent in China, Indonesia, Thailand, and African countries. Specifically, it is highly common in China where Koro is considered a true mental health illness as it is described in the Chinese Classification of Mental Disorders, Second Edition [3] [4]. Furthermore, this psychiatric condition is also found in other nations and areas as well.

Reports in literature note numerous epidemics such as in Singapore in 1967, Thailand in 1976, China in 1982, Nigeria in the 1980s, and so forth [5].

Sex distribution
Age distribution


According to the psychodynamic theories, the psychotic features of Koro develop in response to poor coping skills during stressful times. Additionally, these symptoms occur in patients who imagine a forbidden fantasy or those who seek to evade a particular situation. It is notable though that while overwhelming stress is the basis of this disorder, controlled studies have not corroborated biologic or psychological hypotheses.

Medical conditions
Note that real penile shrinkage may occur in cases with vasoconstriction in the setting of cold temperatures and severe anxiety. This physiological manifestation should be ruled out before Koro is diagnosed.


The underlying beliefs in Koro partly emerge from political and economic uncertainty. While patient education may help bring awareness to the disorder, there are no prevention strategies for patients with deep rooted beliefs and worries. 


Koro is a mental disorder in which the patient is overwhelmed with the belief that there is a shrinkage or retraction of the genital. There is a history of Koro mass hysteria reported in Africa, Asia, and Europe [1] as it is observed in various cultures and ethnicities. This condition is alternatively called genital retraction syndrome in the United States and Europe.

Patients with Koro experience severe anxiety accompanied by the fear of active genital shrinkage and the eventual impending death. Since the ability to procreate is considered paramount in different cultures, individuals affected with this condition develop panic attacks that stem from their worries that they are now impotent and sterile.

Diagnosis of Koro is achieved through a detailed psychological evaluation and a physical exam. The latter is performed to exclude actual diseases that can result in genital retraction [2]. Additionally, Koro should be differentiated from other psychiatric disorders such as body dysmorphic disorder (BDD).

Certain cultures will treat Koro through psychotherapy, antipsychotics, and antidepressants while others prescribe measures such as special food, prayers, and exorcism.

Patient Information

In Koro, the patients have an obsessive fear that their genitals are becoming smaller, retracting back into the body, or disappearing altogether. The patients typically fear that these genital changes are a bad omen and that death for them is imminent.

This mental health disorder occurs in many countries and cultures, especially in Asia and Africa. The traditional Chinese medicine recognizes Koro as a mental health illness, as this disease is prevalent in this population. The term "koro" originates from Malay, which describes the turtle's head when it retracts into its body.

In men beliefs are related to the penis, while in women beliefs are related to nipples. The patients usually develop severe anxiety because they fear that they will die, and worry that they will become sterile and impotent while losing sexual power. Some patients will develop psychotic features such as hallucinations.

Also, these patients and their family members will attempt to repair the retraction by holding their genitals and pulling them out or by using clamps or strings to anchor them.

There are young men who may have misconceptions regarding what is a normal sized penis and the puberty process. Some people will diagnose their own children or even spouses with this disease.

As this is mostly found in East Asian countries, there is likely a cultural syndrome based on worries or rumors. Additionally, there have been sporadic cases in Western countries.

This fictitious disease may be accompanied by other psychiatric illnesses such as Body Dysmorphic Disorder, in which a person is very obsessed with an imagined imperfection in the physical appearance.

Koro is diagnosed through a detailed psychological evaluation. Also, a physical exam is necessary to rule out any disease that may actually cause genital retraction. The medical team should make sure that there are no self-inflicted injuries. Finally, since Koro and Body Dysmorphic Disorder are similar, these should be differentiated by the clinicians.

The main treatment consists of psychotherapy, antipsychotic medications, and antidepressants. In Chinese medicine, the treatment may consist of exorcism, special potions, and foods.



  1. Mattelaer JJ, Jilek W. Koro--the psychological disappearance of the penis. Journal of Sexual Medicine. 2007;4(5):1509-15.
  2. Ghanem H, Glina S, Assalian P, Buvat J. Position Paper: Management of Men Complaining of a Small Penis Despite an Actually Normal Size. Journal of Sexual Medicine. 2013;10(1):294-303.
  3. Culture-bound syndromes. In: American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision. Washington, DC: American Psychiatric Association; 2000.
  4. Bandinelli PL, Trevisi M, Kotzalidis GD, Manfredi G, Rapinesi C, Ducci G. Chronic Koro-like syndrome (KLS) in recurrent depressive disorder as a variant of Cotard's delusion in an Italian male patient. A case report and historical review. Rivista di Psichiatria. 2011;46(3):220-226.
  5. Chowdhury AN. The definition and classification of Koro. Culture, Medicine and Psychiatry.1996; 20(1):41-65.
  6. Jorgensen P, Mortensen PB. Reactive psychosis and mortality. Acta Psychiatrica Scandinavica. 1990; 81(3):277-9.
  7. Correll CU, Smith CW, Auther AM, et al. Predictors of remission, schizophrenia, and bipolar disorder in adolescents with brief psychotic disorder or psychotic disorder not otherwise specified considered at very high risk for schizophrenia. Journal of Child and Adolescent Psychopharmacology. 2008; 18(5):475-90. 
  8. Yap PM. Koro — A Culture-Bound Depersonalization Syndrome. British Journal of Psychiatry. 1965;111:43-50.
  9. Gwee, Ah Leng. Koro — A Cultural Disease. Singapore Medical Journal. 1963;3:119-22.
  10. Dzokoto VA, Adams G. Understanding genital-shrinking epidemics in West Africa : koro, juju or mass psychogenic illness? Culture, Medicine and Psychiatry. 2005;29(1):53-78.
  11. Kim J, Kim M, Lee N, Park Y. A case of urethrocutaneous fistula with the koro syndrome. Journal of Urology. 2000;164(1):123.

Ask Question

5000 Characters left Format the text using: # Heading, **bold**, _italic_. HTML code is not allowed.
By publishing this question you agree to the TOS and Privacy policy.
• Use a precise title for your question.
• Ask a specific question and provide age, sex, symptoms, type and duration of treatment.
• Respect your own and other people's privacy, never post full names or contact information.
• Inappropriate questions will be deleted.
• In urgent cases contact a physician, visit a hospital or call an emergency service!
Last updated: 2019-07-11 22:55