The cause of BIID is unknown and it is unclear if it is neurological, psychological, or both.
Apotemnophilia was first described in a 1977 article by psychologists Gregg Furth and John Money as primarily sexually oriented, in 1986 Money described a similar condition he called "acromotophile", namely sexual arousal over a partner's amputation. Publications before 2004 were generally case studies. The condition received public attention in the late 1990s after a Scottish surgeon, Robert Smith, amputated limbs of two people who were desperate to have this done and were otherwise healthy.
In 2004 Michael First published the first clinical research in which he surveyed 52 people with the condition, a quarter of whom have had an amputation. Based on that work, First coined the term "body integrity identity disorder" to express what he saw as more of an identity disorder than a paraphilia. After First's work, efforts to study BIID as a neurological condition looked for possible causes in the brains of people with BIID using neuroimaging and other techniques. Research provisionally found that people with BIID were more likely to want removal of a left limb than right, in accordance with damage to the right parietal lobe; in addition, skin conductance response is significantly different above and below the line of desired amputation, and the line of desired amputation remains stable over time, with the desire often beginning in early childhood. This work did not completely explain the condition, and psychosexual research has been ongoing as well.
As of 2014 it remained unclear whether BIID is a form of human diversity or a mental disorder, similar to the development of the concept of gender identity disorder. There was debate about including it in the Diagnostic and Statistical Manual of Mental Disorders 5 and it was not included; it is also not included in the International Statistical Classification of Diseases 10. The ethics of surgically amputating the undesired limb of a person with BIID are difficult and controversial.
BIID is a rare, infrequently studied proposed condition in which there is a mismatch between the mental body image and the physical body, characterized by an intense desire for amputation of a limb, usually a leg, or to become blind or deaf. The person sometimes has a sense of sexual arousal connected with the desire for loss of a limb or sense.