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. The syndrome is reported in south and east Asia, where it is known by a variety of local terms, such as shuk yang, shook yong, and suo yang (Chinese); jinjinia bemar (Assam); or rok-joo (Thailand). It is occasionally found in the West. Koro at times occurs in localized epidemic form in east Asian areas. This diagnosis is included in the Chinese Classification of Mental Disorders, Second Edition (CCMD-2).