Stefan Daniel is a 51-year-old German clinical psychologist with multiple sclerosis. He has decided that he will end his life, by taking a barbiturate while sitting in his own living room, when he can no longer see or speak. Esme Nicholson for NPR hide caption

itoggle caption Esme Nicholson for NPR

John Kelly and Dr. Marcia Angell were advocates on opposing sides of a Massachusetts measure to legalize physician-assisted suicide. Jesse Costa/Jesse Costa/WBUR hide caption

itoggle caption Jesse Costa/Jesse Costa/WBUR