Body Integrity Identity Disorder
When a person's idea of how they should look does not match their actual physical form, it can be caused by Body Integrity Identity Disorder. This condition affects a small percentage of the population and is commonly manifested by a desire to have an amputation of a specific body part. In most cases, the limb that the person would like to remove is actually in healthy working order and there are no physical problems with it.
Many psychologists and neurologists have ventured theories into what causes this type of thought. The common leading idea is that Body Integrity Identity Disorder, or BIID, occurs when the brain is not able to provide an accurate plan of the body. In this case, the brain sees the offending limb as being foreign and not actually a part of the person, thus the desire to have it removed.
Some medical experts have also come up with theories that explain a more psychological source of the issues. One of these theories is that a a person with BIID may have seen an amputee at an earlier age and this image has replaced their own thoughts about what constitutes the ideal person. Therefore, to become a better person, they feel that a certain limb or appendage will have to be amputated. Unfortunately, there are no known surgeons that will carry out this type of amputation without a medical reason to perform the operation. In the most severe cases, a person with BIID may do bodily harm to the limb that they would like to have removed, thus necessitating an amputation operation. Others manage to cope with the illness by using canes and prosthetic attachments to help them feel complete. Cases of BIID are often separated into those which have an actual physical problem and those for whom the issue is psychological in nature.