While not impossible, such a thing is rare in actual human beings. 'Catatonic Depression' (Sometimes referred to as 'Catastrophic Depression') is the medical term to describe real-life instances of this. It is possible to turn someone into an Empty Shell, however it requires said person to go through prolonged periods of torment and abuse, and not just regular abuse such as being beaten, molested or bullied, but rather being subjected to '''years''' of nonstop pain and torment that borders on being considered torture. That being said, many people who have actually survived being tortured (Whether they were a POW in a war or just an unlucky victim of a psychopath) are generally expected to, at one point of their lives or another, fit this trope perfectly. Just like how it's possible to turn one into an Empty Shell, it's possible to revert them back to normal, although such a thing usually requires the victim to take huge amounts of antidepressants and years if not decades of psychological assistance and therapy. Just the idea that there have been real-life instances of people being subjected to enough torture to be turned into an Empty Shell is in itself {{High Octane Nightmare Fuel}} when you think about it.