The term body integrity identity disorder (BIID) describes the extremely rare phenomenon of persons who desire the amputation of one or more healthy limbs or who desire a paralysis. Some of these persons mutilate themselves; others ask surgeons for an amputation or for the transection of their spinal cord. Psychologists and physicians explain this phenomenon in quite different ways; but a successful psychotherapeutic or pharmaceutical therapy is not known. Lobbies of persons suffering from BIID explain the desire for amputation in (...) analogy to the desire of transsexuals for surgical sex reassignment. Medical ethicists discuss the controversy about elective amputations of healthy limbs: on the one hand the principle of autonomy is used to deduce the right for body modifications; on the other hand the autonomy of BIID patients is doubted. Neurological results suggest that BIID is a brain disorder producing a disruption of the body image, for which parallels for stroke patients are known. If BIID were a neuropsychological disturbance, which includes missing insight into the illness and a specific lack of autonomy, then amputations would be contraindicated and must be evaluated as bodily injuries of mentally disordered patients. Instead of only curing the symptom, a causal therapy should be developed to integrate the alien limb into the body image. (shrink)