Nothing is more definitive of identity than the life that animates the individual. If any individual is facing debilitating pain and a total loss of any dignified, productive role in his / her society, then that person should be allowed to die and it should be incumbent upon any physician who believes in the Hippocratic oath to assist such a person's suicide.
Why is it considered acceptable for doctors to insist on giving pain stricken people unnecessary, painful, worthless and sometimes harmful tests and medication, but all of a sudden so many doctors are oh-so-self-righteous when asked to do something to actually help the patient in question (e.G. Help a patient that has no hope of regaining his / her life to die)? Doctors are given a huge amount of trust in our society--with such privilege should surely come some responsibility to their patients; it shouldn't be all about making money via worthless tests, pharmaceutical "unspecified research grants" (a reward doctors openly accept from pharmaceutical companies in exchange for pushing whatever expensive and often harmful drug the pharma in question wants to sell). Doctors should be required, under the terms of the hippocratic oath, to do the least amount of harm, and for many patients, suicide would be the least amount of harm--it would be a relief from pain and hopelessness, instead of having more pain and years and years of hopelessness inflicted by doctors who batten on the suffering of the patients that they swear to protect from physical harm from their bodies as best they can.