Zombie Research Society
In the coming zombie plague, panic in the face of extreme stress, or delusional thinking when forced to go it alone will likely be a recipe for certain death. But as easy as is it to fall into these and other psychological pitfalls, it can be devastatingly hard to pull yourself out.
Post Traumatic Stress 
sufferer and mental wellness expert, Michele Rosenthal, uses her own experiences to warn of just how seductive common trauma disorders can be:
“For a long time, even while I felt controlled, manipulated and devastated by my extreme PTSD symptoms, I wouldn’t have given them up, not for anything in the world.”
Rosenthal points out that psychologically damaged thinking often makes us feel safe, and reinforces our new traumatized view of the world. In other words, illogical actions and dangerous assumptions may seem logical and wise inside the reactive loop of trauma.
To fight this hidden danger, solid preparation and a trusted survival team are essential. It may be impossible to get fully ready for the shock of zombies walking the earth. The goal of all One Percenters should be to just get ready enough to survive.
It’s a perfectly viable psychological disorder, especially in the event of a massive zombie outbreak. It would be quite similar to the Cotard Delusion, where the afflicted individual believes that they’ve died. They refuse to eat or participate in normal activites because, well, they think they’re dead. In a world infested by zombies, the psychological dangers are just as real as the physical ones.
The biggest problem with comparing the fictional reactions of people in World War Z (which was taken directly from Matheson’s vampire novel, I Am Legend, btw) is that Cotard Syndrome is not caused by trauma. It is a mental disorder that isn’t associated with any outside factors, but rather occurs because of some physical malfunction in the brain. And it is extremely rare.
It is highly unlikely that people in a zombie outbreak would believe they were zombies and/or act like zombies. Very entertaining story though!
S’true. World War Z said there were a certain number of people who were so traumatized by the experience that they acted like zombies and believed themselves to be zombies, even though they weren’t.