Introduction: One of the strangest kinds of misperceptions of the body is “Body Integrity Dysphoria” (BID), formerly named as “Body Identity Integrity Disorder” (BIID). The affected people have the feeling that a limb is not part of their body. They can feel it, they can use it, they can move it, but they cannot get along with the fact that it is a part of their own body. Most feel the need for an amputation of a leg, others of both legs, some want a palsy and use a wheelchair. Still discussed is whether other disablements such as blindness, dumbness, deafness or a desire to have an incontinency can be included in this diagnosis. This review discusses parallels and differences to transgender/trans identity, body dysmorphic disorder, alien limb syndrome, hemineglect, and self-induced amputations in schizophrenic patients. The cause for the need to be disabled is still unknown; the review gives an overview about psychological and neurological theories of explanation and what kind of therapy may help. Methods: This is a narrative review of about 20 years of research about Body Integrity Dysphoria by the author. Results: Overall, no psychopathological deviations were found, none of the affected persons examined by us were actually delusional or schizophrenic, which underlines that there is a neurological malfunction in the brain that has existed since birth. However, psychological mechanisms intensify the symptoms. There are clear parallels to other forms of interference between the external body and mental body representation. Different types of therapies have been able to provide help to better deal with BID, but there has been little to bring about a real cure. In contrast, BID-affected persons who achieved amputation (or other desired forms of disability) were satisfied and able to return to work. Conclusions: BID remains an enigmatic disorder. We have learned a lot over the past 20 years that the mental and physical bodies do not have to match.