Walking Corpse Syndrome

If more people started suffering from this one, we'd be well on our way to a zombie apocalypse. A disease marred by mental depression and suicidal tendencies, the patient tends to complain of having lost everything. In fact, they are delusional enough to claim they can smell their own rotting skin or feel worms crawling through their body!

Basically, they feel as though they have died and are nothing but a walking corpse. Paraoxically, being dead technically makes them feel as though they are immortal!